Environ Monit Assess (2015) 187:122 DOI 10.1007/s10661-015-4309-9
Electrochemical determination of hydrazine using a ZrO2 nanoparticles-modified carbon paste electrode Sayed Zia Mohammadi & Hadi Beitollahi & Elina Bani Asadi
Received: 29 November 2014 / Accepted: 15 January 2015 # Springer International Publishing Switzerland 2015
Abstract In the present paper, the use of a carbon paste electrode modified by 3-(4′-amino-3′-hydroxy-biphenyl-4-yl)-acrylic acid (3,4′AA) and ZrO2 nanoparticles prepared by a simple and rapid method was described. The heterogeneous electron transfer properties of (3,4′ AA) coupled to ZrO2 nanoparticles at the carbon paste electrode were investigated using cyclic voltammetry, chronoamperometry, and square wave voltammetry in aqueous buffer solutions. Under the optimized conditions, the square wave voltammetric peak currents of hydrazine increased linearly with hydrazine concentrations in the range of 2.5×10−8 to 5.0×10−5 M, and detection limit of 14 nM was obtained for hydrazine. Finally, this modified electrode was used for the determination of hydrazine in water samples, using standard addition method.
Keywords Hydrazine . ZrO2 nanoparticles . Chemically modified electrodes . Carbon paste electrode
S. Z. Mohammadi (*) : E. Bani Asadi Department of Chemistry, Payame Noor University, Tehran, Iran e-mail: [email protected] H. Beitollahi Environment Department, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran
Introduction Hydrazine (N2H4), a liquid colorless compound, is expected to be a human carcinogen. This substance is an excellent reducing agent and is widely employed in many industrial applications as a reagent, catalyst, and corrosion inhibitor. Hydrazine and its derivatives have been used as rocket fuel and as oxygen scavenger in boilers. Other applications include the manufacture of metal films, blowing agents for plastic, photographic chemicals, insecticides, explosives, and pharmaceutics (Leakakos and Shank 1994; Zheng and Shank 1996). Besides being reactive and explosive, hydrazine is highly toxic. It may cause skin irritation and systemic poisoning (Sax 1980). The Environmental Protection Agency (EPA) has classified hydrazine as a probable human carcinogen after studies of increased incidences of lung and liver tumors in mice exposed to hydrazine (Amlathe and Gupta 1988). Because of these considerable toxicological effects and its industrial significance and its high solubility in water, the quantitative determination of hydrazine at micro levels is of great analytical importance attracting the interest of many researchers. Several methods have been described in the literature for the determination of hydrazine in trace amounts using different analytical techniques such as flow injection analysis with fluorimetric (Ensafi and Rezaei 1998), spectrophotometry detection (Evgen’yev et al. 1995), optical chemical sensors (Gojon et al. 1999), chromatography (Shustina and Lesser 1991; Seifart et al. 1995; Kirchherr 1993; Mori et al. 2004), titrimetry (Budkuley
122
Page 2 of 10
1992), chemiluminescence (Safavi and Karimi 2002; Zhike et al. 1996), potentiometric (Mo et al. 2000), amperometry (Jayasri and Sriman 2007), spectrophotometry (Afkhami and Zarei 2004), and capillary electrophoresis (Siangproh et al. 2005). These methods have been described in the literature. Electrochemical measurement techniques have been shown to provide a sensitive and selective approach for the detection of numerous compounds (Goyal et al. 2007; Goyal et al. 2008; Gupta et al. 2006a, 2006b, 2006c, 2006d; Jain et al. 2006; Gupta et al. 2011a, 2011b; Srivastava et al. 1996; Gupta et al. 2006; Mashhadizadeh and Shamsipur 1997; Gupta et al. 2011; Prasad et al. 2004; Gupta et al. 2006; Gupta et al. 2005). Unfortunately, hydrazine, with a large overpotential for oxidization at ordinary electrodes, is not a suitable analyte for these methods. One promising approach for minimizing overvoltage effects is the use of chemically modified electrodes (CMEs) (Pinter et al. 2007; Adekunle and Ozoemena 2008; MazloumArdakani et al. 2010; Beitollahi et al. 2013; Geraldo et al. 2008; Mazloum-Ardakani et al. 2011). Carbon paste electrodes (CPEs) are widely utilized to perform the electrochemical determinations of a variety of species owing to their low residual current and noise, ease of fabrication, wide anodic and cathodic potential ranges, rapid surface renewal, and low cost. Moreover, CMEs can be easily prepared by adding different substances to the bulk of CPEs in order to increase sensitivity, selectivity, and rapidity of determinations (Guo and Khoo 1997; Esfandiari Baghbamidi et al. 2013; Beitollahi et al. 2008; Wang et al. 2013; Yu et al. 2013; Moyo et al. 2014; Devnani and Satsangee 2013; Karimi-Maleh et al. 2014; Brahman et al. 2012; Beitollahi and Sheikhshoaie 2011; Raoof et al. 2006; Mahanthesha et al. 2012; Chitravathi et al. 2012; Beitollahi and Ghorbani 2013; Mokhtari et al. 2012; Serpi et al. 2014; Sun et al. 2013; Beitollahi and Mostafavi 2014; Ghaedi et al. 2012). Nanotechnology represents a rather broad interdisciplinary field of research and industrial activity involving particles less than 100 nm in diameter. Engineered materials made of such small particles exhibit novel properties that are distinctively different from their conventional forms and can affect their physical, chemical, and biological behavior. These nanoscale particles can be tubular (nanotubes), spherical, and irregularly shaped and may also exist in aggregated formations.
Environ Monit Assess (2015) 187:122
Nanoscale particles or nanoparticles (NPs) are not new to science and are ubiquitous in nature. Nanoparticles are by-products of fires, volcanic eruptions, and other natural processes. Nanoparticles are natural components of all living things: many proteins, enzymes, and RNA/DNA actually fit the criteria for NPs. In addition to natural NPs, a number of artificial or engineered NPs have recently been developed. Some of these engineered NPs are already in use in consumer products: titanium oxide, added to cosmetics and zinc oxides, added to sunscreen products. Future applications of NPs show promise in advancing the fields of medical treatment (gene therapy and targeted drug delivery), semiconductors, environmental remediation technology, and electroanalysis (Mahmoudi Moghaddam et al. 2014; Goyal et al. 2008; Oztekin et al. 2012; Beitollahi et al. 2011; Hočevar and Ogorevc 2007; Valle et al. 2012). Electrochemical methods offer the practical advantages including operation simplicity, satisfactory sensitivity, wide linear concentration range, low expense of instrument, possibility of miniaturization, suitability for real-time detection, and less sensitivity to matrix effects in comparison with separation and spectral methods (Goyal et al. 2008; Gupta et al. 2003; 2012; Jain, et al. 1997; Gupta et al. 2013; Jain et al. 2010; Gupta, et al. 2006; Fonseca et al. 2011; Gupta et al. 1999; Gupta et al. 2000; Gupta et al. 2007; Gupta et al. 2002; Gupta et al. 2003). In this paper, we describe the preparation of a new electrode composed of a ZrO2 nanoparticle carbon paste electrode (ZCPE) modified with 3-(4′-amino-3′-hydroxybiphenyl-4-yl)-acrylic acid (3,4′-AAZCPE) and investigate its performance for the electrocatalytic determination of hydrazine in aqueous solutions.
Experimental Apparatus and chemicals The electrochemical measurements were performed with an Autolab potentiostat/galvanostat (PGSTA T302N, Eco Chemie, the Netherlands). The experimental conditions were controlled with General Purpose Electrochemical System (GPES) software. A conventional three-electrode cell was used at 25±1 °C. An Ag/ AgCl/KCl (3.0 M) electrode (Azar electrode, Urmia, Iran), a platinum wire (Azar electrode, Urmia, Iran),
Environ Monit Assess (2015) 187:122
and 3,4-AAZCPE were used as the reference, auxiliary, and working electrodes, respectively. A Metrohm 710 pH meter was used for pH measurements. Hydrazine and all of the other reagents were of analytical grade and were obtained from Merck (Darmstadt, Germany). The buffer solutions were prepared from orthophosphoric acid and its salts (Darmstadt, Germany) in the pH range of 2.0–9.0. 3,4′-AA was synthesized in our laboratory as reported previously (Molaakbari et al. 2014). Preparation of the electrode The 3,4′-AAZCPE were prepared by hand mixing 0.01 g of 3,4′-AA with 0.95 g graphite powder and 0.04 g ZrO2 nanoparticles with a mortar and pestle. Then, ∼0.7 mL of paraffin was added to the above mixture and mixed for 20 min until a uniformly wetted paste was obtained. The paste was then packed into the end of a glass tube (ca. 3.4 mm i.d. and 10 cm long). A copper wire inserted into the carbon paste provided the electrical contact. When necessary, a new surface was obtained by pushing an excess of the paste out of the tube and polishing with a weighing paper. For comparison, 3,4′-AA modified CPE electrode (3,4′-AAZPE) without ZrO2 nanoparticles, ZrO2 nanoparticles paste electrode (ZPE) without 3,4′-AA, and unmodified CPE in the absence of both 3,4′-AA and ZrO2 nanoparticles were also prepared in the same way.
Results and discussion Electrochemical behavior of 3,4-AAZCPE 3,4′-AAZCPE was constructed and its electrochemical properties were studied in a 0.1 M phosphate buffered solution (PBS) (pH 7.0) using cyclic voltammetry (CV). The experimental results show well-defined and reproducible anodic and cathodic peaks with Epa, Epc, and E°′ of 270, 130, and 200 vs. Ag/AgCl/KCl (3.0 M), respectively. The observed peak separation potential, ΔEp =(Epa −Epc) of 140 mV, was greater than the value of 59/ n mV expected for a reversible system (Bard and Faulkner 2001), suggesting that the redox couple of 3,4′-AA in 3,4′-AAZCPE has a quasi-reversible behavior in an aqueous medium. The effect of the potential scan rate (ν) on electrochemical
Page 3 of 10 122
properties of the 3,4′AAGCPE was also studied by CV (Fig. 1). Plots of both the anodic and cathodic peak currents (Ip) were linearly dependent on ν in the range of 25 to 900 mV s−1 (Fig. 1 inset), indicating that the redox process of 3,4′AA at the modified electrode are those anticipated for a surface-confined redox couple (Bard and Faulkner 2001). In addition, the long-term stability of the 3,4′AAZCPE was tested over a 3-week period. When CVs were recorded after the modified electrode was stored in atmosphere at room temperature, the peak potential for hydrazine oxidation was unchanged and the current signals showed less than 2.4 % decrease relative to the initial response. The antifouling properties of the modified electrode toward hydrazine oxidation and its oxidation products were investigated by recording the CVs of the modified electrode before and after use in the presence of hydrazine. CVs were recorded in the presence of hydrazine after having cycled the potential 15 times at a scan rate of 10 mV s−1. The peak potentials were unchanged, and the currents decreased by less than 2.3 %. Therefore, at the surface of 3,4′-AAZCPE, not only the sensitivity increases but also the fouling effect of the analyte and its oxidation product decreases. Electrocatalytic oxidation of hydrazine at 3,4′-AAZCPE Figure 2 depicts the CV responses for the electrochemical oxidation of 5.0 μM hydrazine at unmodified CPE (curve b), ZPE (curve d), 3,4′AACPE (curve e), and 3,4′ AAZCPE (curve f). Also, curve a shows unmodified CPE in 0.1 M PBS (pH 7.0). As it is seen, while the anodic peak potentials for hydrazine oxidation at the ZPE and unmodified CPE are 840 and 890 mV, respectively, the corresponding potential at 3,4′AAZCPE and 3,4′AACPE is ∼270 mV. These results indicate that 3,4′AA can act as a good mediator and peak potential for hydrazine oxidation at the 3,4′AAZCPE and 3,4′ AACPE shift by ∼570 and 620 mV toward negative values compared to ZPE and unmodified CPE, respectively. However, 3,4′AAZCPE shows a much higher anodic peak current for the oxidation of hydrazine compared to 3,4′AACPE, indicating that the combination of ZrO2 nanoparticles and the mediator (3,4′AA) has significantly improved the performance of the electrode toward hydrazine oxidation. In fact, 3,4′AAZCPE in the absence of
122
Page 4 of 10
Environ Monit Assess (2015) 187:122
Fig. 1 CVs of 3,4′AAZCPE in 0.1 M PBS (pH 7.0), at various scan rates, numbers 1–10 correspond to 25, 50, 100, 200, 300, 500, 600, 700, 800, and 900 mV s−1. Inset, variation of anodic and cathodic peak currents vs. scan rate
hydrazine exhibited a well-behaved redox reaction (Fig. 2, curve c) in 0.1 M PBS (pH 7.0). However, Fig. 2 CVs of (a) unmodified CPE in 0.1 M PBS (pH 7.0), (b) unmodified CPE in 5.0 μM hydrazine, (c) 3,4′-AAZCPE in 0.1 M PBS, (d) ZPE in 5.0 μM hydrazine, (e) 3,4′-AACPE in 5.0 μM hydrazine, and (f) 3,4′ AAZCPE in 5.0 μM hydrazine. In all cases, the scan rate was 10 mV s−1
there was a drastic increase in the anodic peak current in the presence of 5.0 μM hydrazine
Environ Monit Assess (2015) 187:122
(curve f), which can be related to the strong electrocatalytic effect of the 3,4′AAZCPE toward this compound (Bard and Faulkner 2001). The effect of scan rate on the electrocatalytic oxidation of hydrazine at the 3,4′-AAZCPE was investigated by linear sweep voltammetry (LSV) (Fig. 3). As can be observed in Fig. 3, the oxidation peak potential shifted to more positive potentials with increasing scan rate, confirming the kinetic limitation in the electrochemical reaction. Also, a plot of peak height (Ip) vs. the square root of scan rate (ν1/2) was found to be linear in the range of 5–30 mV s −1 , suggesting that, at sufficient overpotential, the process is diffusion rather than surface controlled (Bard and Faulkner 2001). A plot of the scan rate-normalized current (Ip/ ν1/2) vs. scan rate (Fig. 3b) exhibits the characteristic shape typical of an EC′ process (Bard and Faulkner 2001). The inset c of Fig. 3 shows a Tafel plot that was drawn from points of the Tafel region of the LSV. The Tafel slope of 0.132 V obtained in this case agrees well with the involvement of one electron in the rate determining step of the electrode process, assuming a charge transfer coefficient of α=0.55 (Bard and Faulkner 2001). Fig. 3 LSVs of 3,4′-AAZCPE in 0.1 M PBS (pH 7.0) containing 2.5 μM hydrazine at various scan rates; from inner to outer scan rates of 5, 10, 15, 20, 25, and 30 mV s−1, respectively. Insets, variation of (a) anodic peak current vs. ν1/2, (b) normalized current (Ip/ν1/2) vs. ν, and (c) anodic peak potential vs. log ν
Page 5 of 10 122
Chronoamperometric measurements Chronoamperometric measurements of hydrazine at 3,4′-AAZCPE were carried out by setting the working electrode potential at 0.35 V vs. Ag/AgCl/KCl (3.0 M) for the various concentrations of hydrazine in 0.1 M PBS (pH 7.0) (Fig. 4). For an electroactive material (hydrazine in this case) with a diffusion coefficient of D, the current observed for the electrochemical reaction at the mass transport limited condition is described by the Cottrell equation (Bard and Faulkner 2001). I ¼ nFAD1=2 C b π−1=2 t −1=2
ð1Þ
where D and C b are the diffusion coefficient (cm2 s−1) and the bulk concentration (mol cm−3), respectively. Experimental plots of I vs. t−1/2 were employed, with the best fits for different concentrations of hydrazine (Fig. 4a). The slopes of the resulting straight lines were then plotted vs. hydrazine concentration (Fig. 4b). From the resulting slope and Cottrell equation, the mean value of D was found to be 1.07×10−6 cm2 s−1.
122
Environ Monit Assess (2015) 187:122
Page 6 of 10
Chronoamperometry can also be employed to evaluate the catalytic rate constant, k, for the reaction between hydrazine and the 3,4′-AAZCPE according to the method described by Galus (Galus 1976): h i I C = I L ¼ γ 1=2 π1=2 er f γ 1=2 þ expð−γ Þ=γ 1=2
ð2Þ
where IC is the catalytic current of hydrazine at the 3,4′AAZCPE, IL is the limited current in the absence of hydrazine, and γ=kCbt is the argument of the error function (Cb is the bulk concentration of hydrazine). In cases where γ exceeds the value of 2, the error function is almost equal to 1 and therefore, the above equation can be shortened to: I C =I L ¼ π1=2 γ 1=2 ¼ π1=2 ðkC b t Þ1=2
ð3Þ
where t is the time elapsed. The above equation can be used to calculate the rate constant, k, of the catalytic process from the slope of IC/IL vs. t1/2 at a given hydrazine concentration. From the values of the slopes (Fig. 4c), the average value of k was found to be 1.5×10 3 M−1 s−1. Fig. 4 Chronoamperograms obtained at 3,4′-AAZCPE in 0.1 M PBS (pH 7.0) for different concentrations of hydrazine. The numbers 1–5 correspond to 0.0, 0.1, 0.3, 0.7, and 1.0 mM of hydrazine. Insets, (a) plots of I vs. t−1/2 obtained from chronoamperograms 2–5. (b) Plot of the slope of the straight lines against hydrazine concentration. (c) Dependence of Ic/Il on t1/2 derived from the data of chronoamperograms 1–5
Calibration plot and limit of detection The electrocatalytic peak current of hydrazine oxidation at the surface of the 3,4′-AAZCPE can be used for determination of hydrazine in solution. Therefore, square wave voltammetry (SWV) experiments were performed using modified electrode in 0.1 M PBS (pH 7.0) containing various concentration of hydrazine (Fig. 5). The plot of peak current vs. hydrazine concentration consisted of two linear segments with slopes of 3.992 and 1.160 μA μM−1 in the concentration ranges of 2.5× 10−8 to 7.5×10−6 M and 7.5 ×10−6 to 5.0× 10−5 M, respectively. The difference in the slopes for the calibration curves is due to the different activity of the electrode surface with low and high concentrations of the analyte. In the lower hydrazine concentration, due to a high number of active sites (in relation to the total number of the analyte molecules), the slope of the first calibration curve is high. While in the higher hydrazine concentration, due to decreasing active sites (in relation to the total number of analyte molecules, mainly at the surface of the electrode), the slope of the second calibration decreased too.
Environ Monit Assess (2015) 187:122
Page 7 of 10 122
Fig. 5 SWVs of 3,4′-AAZCPE in 0.1 M PBS (pH 7.0) containing different concentrations of hydrazine. Numbers 1–10 correspond to 0.025, 0.05, 0.25, 0.5, 2.5, 7.5, 10.0, 20.0, 30.0, and 50.0 μM of hydrazine. Insets, the plots of the electrocatalytic peak current as a function of hydrazine concentration in the range of (a) 0.025–7.5 and (b) 7.5–50.0 μM
Also, the detection limit, Cm, of hydrazine was obtained using the following equation: C m ¼ 3sb =m
measurements of the blank solution. The detection limit (3σ) of hydrazine was found to be 14 nM.
ð4Þ Real sample analysis
In the above equation, m is the slope of the calibration plot (3.992 μA μM−1) in the first linear range (2.5×10−8 to 7.5×10−6 M), and sb is the standard deviation of the blank response which is obtained from 20 replicate
Table 1 The application of 3,4AAZCPE for determination of hydrazine in water samples (n=5)
Sample Drinking water
River water
ND not detected, R.S.D. relative standard deviation
In order to evaluate the analytical applicability of the proposed method, it was also applied to the determination of hydrazine in water samples. The results are listed
Spiked (μM) 0
Found (μM) ND
Recovery (%) –
R.S.D. (%) –
5.0
4.9
98.0
3.2
10.0
10.3
103.0
1.6
15.0
15.3
102.0
2.4
20.0
19.8
99.0
0
ND
–
2.1 –
2.5
2.6
104.0
7.5
7.4
98.7
1.9 3.4
12.5
12.6
100.8
2.6
17.5
17.1
97.7
2.9
122
Page 8 of 10
in Table 1. Satisfactory recovery of the experimental results was found for hydrazine. The reproducibility of the method was demonstrated by the mean relative standard deviation (R.S.D.).
Conclusions The 3,4′-AAZCPE was prepared and used for the investigation of the electrochemical behavior of hydrazine. Two pairs of well-defined redox peaks were obtained at the 3,4′-AAZCPE. The 3,4′-AAZCPE showed excellent electrocatalytic activity for the hydrazine. The SWV currents of hydrazine at 3,4′-AAZCPE increased linearly with the hydrazine concentration in the range from 2.5×10−8 to 5.0×10−5 M with a detection limit of 14 nM. Finally, this method was used for the determination of hydrazine in water samples. Acknowledgements The authors wish to thank Payame Noor University for support of this work.
References Adekunle, A. S., & Ozoemena, K. I. (2008). Insights into the electro-oxidation of hydrazine at single-walled carbonnanotube-modified edge-plane pyrolytic graphite electrodes electro-decorated with metal and metal oxide films. Journal of Solid State Electrochemistry, 12(10), 1325–1336. Afkhami, A., & Zarei, A. R. (2004). Simultaneous spectrophotometric determination of hydrazine and phenylhydrazine based on their condensation reactions with different aromatic aldehydes in micellar media using Hpoint standard addition method. Talanta, 62(3), 559–565. Amlathe, S., & Gupta, V. K. (1988). Spectrophotometric determination of trace amounts of hydrazine in polluted water. Analyst, 113(9), 1481–1483. Bard, A. J., & Faulkner, L. R. (2001). Electrochemical methods fundamentals and applications (2nd ed.). New York: Wiley. Beitollahi, H., & Ghorbani, F. (2013). Benzoylferrocene-modified carbon nanotubes paste electrode as a voltammetric sensor for determination of hydrochlorothiazide in pharmaceutical and biological samples. Ionics, 19(11), 1673–1679. Beitollahi, H., & Mostafavi, M. (2014). Nanostructured base electrochemical sensor for simultaneous quantification and voltammetric studies of levodopa and carbidopa in pharmaceutical products and biological samples. Electroanalysis, 26(5), 1090–1098. Beitollahi, H., & Sheikhshoaie, I. (2011). Electrocatalytic and simultaneous determination of isoproterenol, uric acid and folic acid at molybdenum (VI) complex-carbon nanotube paste electrode. Electrochimica Acta, 56(27), 10259–10263.
Environ Monit Assess (2015) 187:122 Beitollahi, H., Karimi-Maleh, H., & Khabazzadeh, H. (2008). Nanomolar and selective determination of epinephrine in the presence of norepinephrine using carbon paste electrode modified with carbon nanotubes and novel 2-(4-Oxo-3-phenyl-3,4dihydroquinazolinyl)- N′-phenyl-hydrazinecarbothioamide. Analytical Chemistry, 80(24), 9848–9851. Beitollahi, H., Raoof, J. B., & Hosseinzadeh, R. (2011). Application of a carbon-paste electrode modified with 2,7bis(ferrocenyl ethyl)fluoren-9-one and carbon nanotubes for voltammetric determination of levodopa in the presence of uric acid and folic acid. Electroanalysis, 23(8), 1934–1940. Beitollahi, H., Tajik, S., Karimi Maleh, H., & Hosseinzadeh, R. (2013). Application of a 1-benzyl-4-ferrocenyl-1H-[1,2,3]triazole/carbon nanotube modified glassy carbon electrode for voltammetric determination of hydrazine in water samples. Applied Organometalic Chemistry, 27(8), 444–450. Brahman, P. K., Dar, R. A., Tiwari, S., & Pitre, K. S. (2012). Voltammetric determination of anticancer drug flutamide in surfactant media at polymer film modified carbon paste electrode. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 396, 8–15. Budkuley, J. S. (1992). Determination of hydrazine and sulphite in the presence of one another. Microchimica Acta, 108(1–2), 103–105. Chitravathi, S., Kumara Swamy, B. E., Mamatha, G. P., & Sherigara, B. S. (2012). Electrochemical behavior of poly (naphthol green B)-film modified carbon paste electrode and its application for the determination of dopamine and uric acid. Journal of Electroanalytical Chemistry, 667, 66–75. Devnani, H., & Satsangee, S. P. (2013). Voltammetric trace determination of mercury using plant refuse modified carbon paste electrodes. Environmental Monitoring and Assessment, 185(11), 9333–9342. Ensafi, A. A., & Rezaei, B. (1998). Flow injection determination of hydrazine with fluorimetric detection. Talanta, 47(3), 645–649. Esfandiari Baghbamidi, S., Beitollahi, H., Mohammadi, S. Z., Tajik, S., Soltani-Nejad, S., & Soltani-Nejad, V. (2013). Nanostructure-based electrochemical sensor for the voltammetric determination of benserazide, uric acid, and folic acid. Chinese Journal of Catalysis, 34(10), 1869–1875. Evgen’yev, M. I., Garmonov, S. Y., Evgen’yeva, I. I., & Budnikov, H. C. (1995). Determination of hydrazine derivatives by flow-injection analysis with spectrophotometric detection. Talanta, 42(10), 1465–1469. Fonseca, J., Dohrn, R., & Peper, S. (2011). High-pressure fluid phase equilibria: experimental methods and systems investigated. Critical Reviews in Analytical Chemistry, 41, 282–313. Galus, Z. (1976). Fundamentals of electrochemical analysis. New York: Ellis Horwood. Geraldo, D. A., Togo, C. A., Limson, J., & Nyokong, T. (2008). Electrooxidation of hydrazine catalyzed by noncovalently functionalized single-walled carbon nanotubes with CoPc. Electrochimica Acta, 53(27), 8051–8057. Ghaedi, M., Naderi, S., Montazerozohori, M., Sahraei, R., Daneshfar, A., & Taghavimoghadam, N. (2012). Modified carbon paste electrodes for Cu(II) determination. Materials Science and Engineering C, 32(8), 2274–2279. Gojon, C., Dureault, B., Hovnanian, N., & Guizard, C. (1999). Optical chemical hydrazine sensor from hybrid organicinorganic materials. Journal of Sol-Gel Science and Technology, 14(2), 163–173.
Environ Monit Assess (2015) 187:122 Goyal, R. N., Gupta, V. K., & Bachheti, N. (2007). Fullerene-C60modified electrode as a sensitive voltammetric sensor for detection of nandrolone—an anabolic steroid used in doping. Analytica Chimica Acta, 597, 82–89. Goyal, R. N., Gupta, V. K., Bachheti, N., & Sharma, R. N. (2008). Electrochemical sensor for the determination of dopamine in presence of high concentration of ascorbic acid using a fullerene-C60 coated gold electrode. Electroanalysis, 20, 757–764. Guo, S. X., & Khoo, S. B. (1997). Formation of a mercury plated carbon paste electrode by electroreduction of a mercury(II) diethyldithiocarbamate modified carbon paste. Environmental Monitoring and Assessment, 44(1–3), 471–480. Gupta, V. K., Mangla, R., Khurana, U., & Kumar, P. (1999). Determination of uranyl ions using poly (vinyl chloride) based 4-tert-butylcalix [6] arene membrane sensor. Electroanalysis, 11, 573–576. Gupta, V. K., Prasad, R., Kumar, P., & Mangla, R. (2000). New nickel(II) selective potentiometric sensor based on 5,7,12,14tetramethyldibenzotetraazaannulene in a poly(vinyl chloride) matrix. Analytica Chimica Acta, 420, 19–27. Gupta, V. K., Chandra, S., & Mangla, R. (2002). Dicyclohexano- 18-crown-6 as active material in PVC matrix membrane for the fabrication of cadmium selective potentiometric sensor. Electrochimica Acta, 47, 1579–1586. Gupta, V. K., Jain, S., & Chandra, S. (2003). Chemical sensor for lanthanum(III) determination using aza-crown as ionophore in poly(vinyl chloride) matrix. Analytica Chimica Acta, 486, 199– 207. Gupta, V. K., Chandra, S., & Lang, H. (2005). A highly selective mercury electrode based on a diamine donor ligand. Talanta, 66, 575–580. Gupta, V. K., Jain, A. K., Kumar, P., Agarwal, S., & Maheshwari, G. (2006a). Chromium(III)-selective sensor based on triothymotide in PVC matrix. Sensors and Actuators B: Chemical, 113, 182–186. Gupta, V. K., Jain, A. K., Maheshwari, G., Lang, H., & Ishtaiwi, Z. (2006b). Copper(II)-selective potentiometric sensors based on porphyrins in PVC matrix. Sensors and Actuators B: Chemical, 117, 99–106. Gupta, V. K., Jain, A. K., & Kumar, P. (2006c). PVCbased membranes of N, N’-dibenzyl-1,4,10,13tetraoxa-7,16- diazacyclooctadecane as Pb(II)-selective sensor. Sensors and Actuators B: Chemical, 120, 259–265. Gupta, V. K., Singh, A. K., Mehtab, S., & Gupta, B. (2006d). A cobalt(II)-selective PVC membrane based on a Schiff base complex of N, N’-bis(salicylidene)-3,4-diaminotoluene. Analytica Chimica Acta, 566, 5–10. Gupta, V. K., Singh, A. K., Khayat, M. A. I., & Gupta, B. (2007). Neutral carriers based polymeric membrane electrodes for selective determination of mercury (II). Analytica Chimica Acta, 590, 81–90. Gupta, V. K., Jain, R., Radhapyari, K., Jadon, N., & Agarwal, S. (2011a). Voltammetric techniques for the assay of pharmaceuticals—a review. Analytical Biochemistry, 408, 179–196. Gupta, V. K., Nayak, A., Agarwal, S., & Singhal, B. (2011b). Recent advances on potentiometric membrane sensors for pharmaceutical analysis. Combinatorial Chemistry & High Throughput Screening, 14(4), 284–302.
Page 9 of 10 122 Gupta, V. K., Singh, L. P., Singh, R., Upadhyay, N., Kaur, S. R., & Sethi, B. (2012). A novel copper (II) selective sensor based on dimethyl 4, 4′ (o-phenylene) bis(3-thioallophanate) in PVC matrix. Journal of Molecular Liquids, 174, 11–16. Gupta, V. K., Sethi, B., Sharma, R. A., Agarwa, S., & Bharti, A. (2013). Mercury selective potentiometric sensor based on low rim functionalized thiacalix [4]-arene as a cationic receptor. Journal of Molecular Liquids, 177, 114–118. Hočevar, S. B., & Ogorevc, B. (2007). Preparation and characterization of carbon paste micro-electrode based on carbon nano-particles. Talanta, 74(3), 405–411. Jain, A. K., Gupta, V. K., Singh, L. P., & Khurana, U. (1997). Macrocycle based membrane sensors for the determination of cobalt(II) ions. Analyst, 122, 583–586. Jain, A. K., Gupta, V. K., Singh, L. P., & Raisoni, J. R. (2006). A comparative study of Pb2+ 11 sensors based on derivatized tetrapyrazole and calix[4]arene receptors. Electrochimica Acta, 51, 2547–2553. Jain, R., Gupta, V. K., Jadon, N., & Radhapyari, K. (2010). Voltammetric determination of cefixime in pharmaceuticals and biological fluids. Analytical Biochemistry, 407, 79–88. Jayasri, D., & Sriman, N. S. (2007). Amperometric determination of hydrazine at manganese hexacyanoferrate modified graphite–wax composite electrode. Journal of Hazardous Materials, 144(1–2), 348–354. Karimi-Maleh, H., Tahernejad-Javazmi, F., Ensafi, A. A., Moradi, R., Mallakpour, S., & Beitollahi, H. (2014). A high sensitive biosensor based on FePt/CNTs nanocomposite/N-(4-hydroxyphenyl)-3,5-dinitrobenzamide modified carbon paste electrode for simultaneous determination of glutathione and piroxicam. Biosensors and Bioelectronics, 60, 1–7. Kirchherr, H. (1993). Determination of hydrazine in human plasma by high-performance liquid chromatography. Journal of Chromatography B, 617(1), 157–162. Leakakos, T., & Shank, R. C. (1994). Hydrazine genotoxicity in the neonatal rat. Toxicology and Applied Pharmacology, 126(2), 295–300. Mahanthesha, K. R., Kumara Swamy, B. E., Chandra, U., Sharath Shankar, S., & Pai, K. V. (2012). Electrocatalytic oxidation of dopamine at murexide and TX-100 modified carbon paste electrode: a cyclic voltammetric study. Journal of Molecular Liquids, 172, 119–124. Mahmoudi Moghaddam, H., Beitollahi, H., Tajik, S., Malakootian, M., & Karimi Maleh, H. (2014). Simultaneous determination of hydroxylamine and phenol using a nanostructure-based electrochemical sensor. Environmental Monitoring and Assessment, 186(11), 7431–7441. Mashhadizadeh, M. H., & Shamsipur, M. (1997). Silver(I)-selective membrane electrode based on hexathia-18-crown-6. Electroanalysis, 9, 478–480. Mazloum-Ardakani, M., Rajabi, H., Mirjalili, B. B. F., Beitollahi, H., & Akbari, A. (2010). Nanomolar determination of hydrazine by TiO2 nanoparticles modified carbon paste electrode. Journal of Solid State Electrochemistry, 14(12), 2285–2292. Mazloum-Ardakani, M., Taleat, Z., Beitollahi, H., & Naeimi, H. (2011). Nanomolar concentrations determination of hydrazine by a modified carbon paste electrode incorporating TiO2 nanoparticles. Nanoscale, 3(4), 1683–1689. Mo, J.-W., Ogorevc, B., Zhang, X., & Pihlar, B. (2000). Cobalt and copper hexacyanoferrate modified carbon fiber
122
Page 10 of 10
microelectrode as an all-solid potentiometric microsensor for hydrazine. Electroanalysis, 12(1), 48–54. Mokhtari, A., Karimi-Maleh, H., Ensafi, A. A., & Beitollahi, H. (2012). Application of modified multiwall carbon nanotubes paste electrode for simultaneous voltammetric determination of morphine and diclofenac in biological and pharmaceutical samples. Sensors and Actuators B: Chemical, 169, 96–105. Molaakbari, E., Mostafavi, A., & Beitollahi, H. (2014). First electrochemical report for simultaneous determination of norepinephrine, tyrosine and nicotine using a nanostructure based sensor. Electroanalysis, 26, 2252–2260. Mori, M., Tanaka, K., Xu, Q., Ikedo, M., Taoda, H., & Hu, W. (2004). Highly sensitive determination of hydrazine by ionexclusion chromatography with ion-exchange enhancement of conductivity detection. Journal of Chromatography A, 1039(1–2), 135–139. Moyo, M., Okonkwo, J. O., & Agyei, N. M. (2014). Maize tasselmodified carbon paste electrode for voltammetric determination of Cu(II). Environmental Monitoring and Assessment, 186(8), 4807–4817. Oztekin, Y., Tok, M., Bilici, E., Mikoliunaite, L., Yazicigil, Z., Ramanaviciene, A., & Ramanavicius, A. (2012). Copper nanoparticle modified carbon electrode for determination of dopamine. Electrochimica Acta, 76, 201–207. Pinter, J. S., Brown, K. L., Young, P. A. D., & Peaslee, G. F. (2007). Amperometric detection of hydrazine by cyclic voltammetry and flow injection analysis using ruthenium modified glassy carbon electrodes. Talanta, 71(3), 1219–1225. P r a s a d , R . , G u p t a , V. K . , & K u m a r, A . ( 2 0 0 4 ) . Metallotetraazaporphyrin based anion sensors: regulation of sensor characteristics through central metal ion coordination. Analytica Chimica Acta, 508, 61–70. Raoof, J. B., Ojani, R., Beitollahi, H., & Hosseinzadeh, R. (2006). Electrocatalytic oxidation and highly selective voltammetric determination of l-cysteine at the surface of a1-[4-(ferrocenyl ethynyl)phenyl]-1-ethanone modified carbon paste electrode. Analytical Sciences, 22(9), 1213–1220. Safavi, A., & Karimi, M. A. (2002). Flow injection chemiluminescence determination of hydrazine by oxidation with chlorinated isocyanurates. Talanta, 58(4), 785–792. Sax, N. I. (1980). Dangerous properties of industrial materials (4th ed., p. 814). New York: van Nostrand-Reinhold. Seifart, H. I., Gent, W. L., Parkin, D. P., van Jaarsveld, P. P., & Donald, P. R. (1995). High-performance liquid
Environ Monit Assess (2015) 187:122 chromatographic determination of isoniazid, acetylisoniazid and hydrazine in biological fluids. Journal of Chromatography B, 674(2), 269–275. Serpi, C., Kovatsi, L., & Girousi, S. (2014). Electroanalytical quantification of total dsDNA extracted from human sample using, an ionic liquid modified, carbon nanotubes paste electrode. Analytica Chimica Acta, 812, 26–32. Shustina, R., & Lesser, J. H. (1991). Liquid chromatographic determination of hydrazine, carbohydrazide and thiocarbohydrazide in aqueous solutions. Journal of Chromatography A, 464(28), 208–212. Siangproh, W., Chailapakul, O., Laocharoensuk, R., & Wang, J. (2005). Microchip capillary electrophoresis/electrochemical detection of hydrazine compounds at a cobalt phthalocyanine modified electrochemical detector. Talanta, 67(5), 903–907. Srivastava, S. K., Gupta, V. K., & Jain, S. (1996). PVC-based 2,2, 2-cryptand sensor for zinc ions. Analytical Chemistry, 68, 1272–1275. Sun, W., Wang, Y., Gong, S., Cheng, Y., Shi, F., & Sun, Z. (2013). Application of poly(acridine orange) and graphene modified carbon/ionic liquid paste electrode for the sensitive electrochemical detection of rutin. Electrochimica Acta, 109, 298– 304. Valle, M. A., Gacitua, M., Diaz, F. R., Armijo, F., & Soto, J. P. (2012). Electro-synthesis and characterization of polythiophene nano-wires/platinum nano-particles composite electrodes. Study of formic acid electro-catalytic oxidation. Electrochimica Acta, 71, 277–282. Wang, Y., Wu, Y., Xie, J., & Hu, X. (2013). Metal–organic framework modified carbon paste electrode for lead sensor. Sensors and Actuators B: Chemical, 177, 1161–1166. Yu, X., Chen, Y., Chang, Z. L., Tang, F., & Wu, X. (2013). βCyclodextrin non-covalently modified ionic liquid-based carbon paste electrode as a novel voltammetric sensor for specific detection of bisphenol A. Sensors and Actuators B: Chemical, 186, 648–656. Zheng, H., & Shank, R. C. (1996). Changes in methyl-sensitive restriction sites of liver DNA from hamsters chronically exposed to hydrazine sulfate. Carcinogenesis, 17(12), 2711–2717. Zhike, H., Xinglian, L., Qingyao, L., Hongwu, T., Ximao, Y., Hui, C., & Yune, Z. (1996). Automatic injection analysis with chemiluminescence: detection determination of hydrazine. Microchemical Journal, 53(3), 356–360.
Electrochemical determination of hydrazine using a ZrO2 nanoparticles-modified carbon paste electrode Sayed Zia Mohammadi & Hadi Beitollahi & Elina Bani Asadi
Received: 29 November 2014 / Accepted: 15 January 2015 # Springer International Publishing Switzerland 2015
Abstract In the present paper, the use of a carbon paste electrode modified by 3-(4′-amino-3′-hydroxy-biphenyl-4-yl)-acrylic acid (3,4′AA) and ZrO2 nanoparticles prepared by a simple and rapid method was described. The heterogeneous electron transfer properties of (3,4′ AA) coupled to ZrO2 nanoparticles at the carbon paste electrode were investigated using cyclic voltammetry, chronoamperometry, and square wave voltammetry in aqueous buffer solutions. Under the optimized conditions, the square wave voltammetric peak currents of hydrazine increased linearly with hydrazine concentrations in the range of 2.5×10−8 to 5.0×10−5 M, and detection limit of 14 nM was obtained for hydrazine. Finally, this modified electrode was used for the determination of hydrazine in water samples, using standard addition method.
Keywords Hydrazine . ZrO2 nanoparticles . Chemically modified electrodes . Carbon paste electrode
S. Z. Mohammadi (*) : E. Bani Asadi Department of Chemistry, Payame Noor University, Tehran, Iran e-mail: [email protected] H. Beitollahi Environment Department, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran
Introduction Hydrazine (N2H4), a liquid colorless compound, is expected to be a human carcinogen. This substance is an excellent reducing agent and is widely employed in many industrial applications as a reagent, catalyst, and corrosion inhibitor. Hydrazine and its derivatives have been used as rocket fuel and as oxygen scavenger in boilers. Other applications include the manufacture of metal films, blowing agents for plastic, photographic chemicals, insecticides, explosives, and pharmaceutics (Leakakos and Shank 1994; Zheng and Shank 1996). Besides being reactive and explosive, hydrazine is highly toxic. It may cause skin irritation and systemic poisoning (Sax 1980). The Environmental Protection Agency (EPA) has classified hydrazine as a probable human carcinogen after studies of increased incidences of lung and liver tumors in mice exposed to hydrazine (Amlathe and Gupta 1988). Because of these considerable toxicological effects and its industrial significance and its high solubility in water, the quantitative determination of hydrazine at micro levels is of great analytical importance attracting the interest of many researchers. Several methods have been described in the literature for the determination of hydrazine in trace amounts using different analytical techniques such as flow injection analysis with fluorimetric (Ensafi and Rezaei 1998), spectrophotometry detection (Evgen’yev et al. 1995), optical chemical sensors (Gojon et al. 1999), chromatography (Shustina and Lesser 1991; Seifart et al. 1995; Kirchherr 1993; Mori et al. 2004), titrimetry (Budkuley
122
Page 2 of 10
1992), chemiluminescence (Safavi and Karimi 2002; Zhike et al. 1996), potentiometric (Mo et al. 2000), amperometry (Jayasri and Sriman 2007), spectrophotometry (Afkhami and Zarei 2004), and capillary electrophoresis (Siangproh et al. 2005). These methods have been described in the literature. Electrochemical measurement techniques have been shown to provide a sensitive and selective approach for the detection of numerous compounds (Goyal et al. 2007; Goyal et al. 2008; Gupta et al. 2006a, 2006b, 2006c, 2006d; Jain et al. 2006; Gupta et al. 2011a, 2011b; Srivastava et al. 1996; Gupta et al. 2006; Mashhadizadeh and Shamsipur 1997; Gupta et al. 2011; Prasad et al. 2004; Gupta et al. 2006; Gupta et al. 2005). Unfortunately, hydrazine, with a large overpotential for oxidization at ordinary electrodes, is not a suitable analyte for these methods. One promising approach for minimizing overvoltage effects is the use of chemically modified electrodes (CMEs) (Pinter et al. 2007; Adekunle and Ozoemena 2008; MazloumArdakani et al. 2010; Beitollahi et al. 2013; Geraldo et al. 2008; Mazloum-Ardakani et al. 2011). Carbon paste electrodes (CPEs) are widely utilized to perform the electrochemical determinations of a variety of species owing to their low residual current and noise, ease of fabrication, wide anodic and cathodic potential ranges, rapid surface renewal, and low cost. Moreover, CMEs can be easily prepared by adding different substances to the bulk of CPEs in order to increase sensitivity, selectivity, and rapidity of determinations (Guo and Khoo 1997; Esfandiari Baghbamidi et al. 2013; Beitollahi et al. 2008; Wang et al. 2013; Yu et al. 2013; Moyo et al. 2014; Devnani and Satsangee 2013; Karimi-Maleh et al. 2014; Brahman et al. 2012; Beitollahi and Sheikhshoaie 2011; Raoof et al. 2006; Mahanthesha et al. 2012; Chitravathi et al. 2012; Beitollahi and Ghorbani 2013; Mokhtari et al. 2012; Serpi et al. 2014; Sun et al. 2013; Beitollahi and Mostafavi 2014; Ghaedi et al. 2012). Nanotechnology represents a rather broad interdisciplinary field of research and industrial activity involving particles less than 100 nm in diameter. Engineered materials made of such small particles exhibit novel properties that are distinctively different from their conventional forms and can affect their physical, chemical, and biological behavior. These nanoscale particles can be tubular (nanotubes), spherical, and irregularly shaped and may also exist in aggregated formations.
Environ Monit Assess (2015) 187:122
Nanoscale particles or nanoparticles (NPs) are not new to science and are ubiquitous in nature. Nanoparticles are by-products of fires, volcanic eruptions, and other natural processes. Nanoparticles are natural components of all living things: many proteins, enzymes, and RNA/DNA actually fit the criteria for NPs. In addition to natural NPs, a number of artificial or engineered NPs have recently been developed. Some of these engineered NPs are already in use in consumer products: titanium oxide, added to cosmetics and zinc oxides, added to sunscreen products. Future applications of NPs show promise in advancing the fields of medical treatment (gene therapy and targeted drug delivery), semiconductors, environmental remediation technology, and electroanalysis (Mahmoudi Moghaddam et al. 2014; Goyal et al. 2008; Oztekin et al. 2012; Beitollahi et al. 2011; Hočevar and Ogorevc 2007; Valle et al. 2012). Electrochemical methods offer the practical advantages including operation simplicity, satisfactory sensitivity, wide linear concentration range, low expense of instrument, possibility of miniaturization, suitability for real-time detection, and less sensitivity to matrix effects in comparison with separation and spectral methods (Goyal et al. 2008; Gupta et al. 2003; 2012; Jain, et al. 1997; Gupta et al. 2013; Jain et al. 2010; Gupta, et al. 2006; Fonseca et al. 2011; Gupta et al. 1999; Gupta et al. 2000; Gupta et al. 2007; Gupta et al. 2002; Gupta et al. 2003). In this paper, we describe the preparation of a new electrode composed of a ZrO2 nanoparticle carbon paste electrode (ZCPE) modified with 3-(4′-amino-3′-hydroxybiphenyl-4-yl)-acrylic acid (3,4′-AAZCPE) and investigate its performance for the electrocatalytic determination of hydrazine in aqueous solutions.
Experimental Apparatus and chemicals The electrochemical measurements were performed with an Autolab potentiostat/galvanostat (PGSTA T302N, Eco Chemie, the Netherlands). The experimental conditions were controlled with General Purpose Electrochemical System (GPES) software. A conventional three-electrode cell was used at 25±1 °C. An Ag/ AgCl/KCl (3.0 M) electrode (Azar electrode, Urmia, Iran), a platinum wire (Azar electrode, Urmia, Iran),
Environ Monit Assess (2015) 187:122
and 3,4-AAZCPE were used as the reference, auxiliary, and working electrodes, respectively. A Metrohm 710 pH meter was used for pH measurements. Hydrazine and all of the other reagents were of analytical grade and were obtained from Merck (Darmstadt, Germany). The buffer solutions were prepared from orthophosphoric acid and its salts (Darmstadt, Germany) in the pH range of 2.0–9.0. 3,4′-AA was synthesized in our laboratory as reported previously (Molaakbari et al. 2014). Preparation of the electrode The 3,4′-AAZCPE were prepared by hand mixing 0.01 g of 3,4′-AA with 0.95 g graphite powder and 0.04 g ZrO2 nanoparticles with a mortar and pestle. Then, ∼0.7 mL of paraffin was added to the above mixture and mixed for 20 min until a uniformly wetted paste was obtained. The paste was then packed into the end of a glass tube (ca. 3.4 mm i.d. and 10 cm long). A copper wire inserted into the carbon paste provided the electrical contact. When necessary, a new surface was obtained by pushing an excess of the paste out of the tube and polishing with a weighing paper. For comparison, 3,4′-AA modified CPE electrode (3,4′-AAZPE) without ZrO2 nanoparticles, ZrO2 nanoparticles paste electrode (ZPE) without 3,4′-AA, and unmodified CPE in the absence of both 3,4′-AA and ZrO2 nanoparticles were also prepared in the same way.
Results and discussion Electrochemical behavior of 3,4-AAZCPE 3,4′-AAZCPE was constructed and its electrochemical properties were studied in a 0.1 M phosphate buffered solution (PBS) (pH 7.0) using cyclic voltammetry (CV). The experimental results show well-defined and reproducible anodic and cathodic peaks with Epa, Epc, and E°′ of 270, 130, and 200 vs. Ag/AgCl/KCl (3.0 M), respectively. The observed peak separation potential, ΔEp =(Epa −Epc) of 140 mV, was greater than the value of 59/ n mV expected for a reversible system (Bard and Faulkner 2001), suggesting that the redox couple of 3,4′-AA in 3,4′-AAZCPE has a quasi-reversible behavior in an aqueous medium. The effect of the potential scan rate (ν) on electrochemical
Page 3 of 10 122
properties of the 3,4′AAGCPE was also studied by CV (Fig. 1). Plots of both the anodic and cathodic peak currents (Ip) were linearly dependent on ν in the range of 25 to 900 mV s−1 (Fig. 1 inset), indicating that the redox process of 3,4′AA at the modified electrode are those anticipated for a surface-confined redox couple (Bard and Faulkner 2001). In addition, the long-term stability of the 3,4′AAZCPE was tested over a 3-week period. When CVs were recorded after the modified electrode was stored in atmosphere at room temperature, the peak potential for hydrazine oxidation was unchanged and the current signals showed less than 2.4 % decrease relative to the initial response. The antifouling properties of the modified electrode toward hydrazine oxidation and its oxidation products were investigated by recording the CVs of the modified electrode before and after use in the presence of hydrazine. CVs were recorded in the presence of hydrazine after having cycled the potential 15 times at a scan rate of 10 mV s−1. The peak potentials were unchanged, and the currents decreased by less than 2.3 %. Therefore, at the surface of 3,4′-AAZCPE, not only the sensitivity increases but also the fouling effect of the analyte and its oxidation product decreases. Electrocatalytic oxidation of hydrazine at 3,4′-AAZCPE Figure 2 depicts the CV responses for the electrochemical oxidation of 5.0 μM hydrazine at unmodified CPE (curve b), ZPE (curve d), 3,4′AACPE (curve e), and 3,4′ AAZCPE (curve f). Also, curve a shows unmodified CPE in 0.1 M PBS (pH 7.0). As it is seen, while the anodic peak potentials for hydrazine oxidation at the ZPE and unmodified CPE are 840 and 890 mV, respectively, the corresponding potential at 3,4′AAZCPE and 3,4′AACPE is ∼270 mV. These results indicate that 3,4′AA can act as a good mediator and peak potential for hydrazine oxidation at the 3,4′AAZCPE and 3,4′ AACPE shift by ∼570 and 620 mV toward negative values compared to ZPE and unmodified CPE, respectively. However, 3,4′AAZCPE shows a much higher anodic peak current for the oxidation of hydrazine compared to 3,4′AACPE, indicating that the combination of ZrO2 nanoparticles and the mediator (3,4′AA) has significantly improved the performance of the electrode toward hydrazine oxidation. In fact, 3,4′AAZCPE in the absence of
122
Page 4 of 10
Environ Monit Assess (2015) 187:122
Fig. 1 CVs of 3,4′AAZCPE in 0.1 M PBS (pH 7.0), at various scan rates, numbers 1–10 correspond to 25, 50, 100, 200, 300, 500, 600, 700, 800, and 900 mV s−1. Inset, variation of anodic and cathodic peak currents vs. scan rate
hydrazine exhibited a well-behaved redox reaction (Fig. 2, curve c) in 0.1 M PBS (pH 7.0). However, Fig. 2 CVs of (a) unmodified CPE in 0.1 M PBS (pH 7.0), (b) unmodified CPE in 5.0 μM hydrazine, (c) 3,4′-AAZCPE in 0.1 M PBS, (d) ZPE in 5.0 μM hydrazine, (e) 3,4′-AACPE in 5.0 μM hydrazine, and (f) 3,4′ AAZCPE in 5.0 μM hydrazine. In all cases, the scan rate was 10 mV s−1
there was a drastic increase in the anodic peak current in the presence of 5.0 μM hydrazine
Environ Monit Assess (2015) 187:122
(curve f), which can be related to the strong electrocatalytic effect of the 3,4′AAZCPE toward this compound (Bard and Faulkner 2001). The effect of scan rate on the electrocatalytic oxidation of hydrazine at the 3,4′-AAZCPE was investigated by linear sweep voltammetry (LSV) (Fig. 3). As can be observed in Fig. 3, the oxidation peak potential shifted to more positive potentials with increasing scan rate, confirming the kinetic limitation in the electrochemical reaction. Also, a plot of peak height (Ip) vs. the square root of scan rate (ν1/2) was found to be linear in the range of 5–30 mV s −1 , suggesting that, at sufficient overpotential, the process is diffusion rather than surface controlled (Bard and Faulkner 2001). A plot of the scan rate-normalized current (Ip/ ν1/2) vs. scan rate (Fig. 3b) exhibits the characteristic shape typical of an EC′ process (Bard and Faulkner 2001). The inset c of Fig. 3 shows a Tafel plot that was drawn from points of the Tafel region of the LSV. The Tafel slope of 0.132 V obtained in this case agrees well with the involvement of one electron in the rate determining step of the electrode process, assuming a charge transfer coefficient of α=0.55 (Bard and Faulkner 2001). Fig. 3 LSVs of 3,4′-AAZCPE in 0.1 M PBS (pH 7.0) containing 2.5 μM hydrazine at various scan rates; from inner to outer scan rates of 5, 10, 15, 20, 25, and 30 mV s−1, respectively. Insets, variation of (a) anodic peak current vs. ν1/2, (b) normalized current (Ip/ν1/2) vs. ν, and (c) anodic peak potential vs. log ν
Page 5 of 10 122
Chronoamperometric measurements Chronoamperometric measurements of hydrazine at 3,4′-AAZCPE were carried out by setting the working electrode potential at 0.35 V vs. Ag/AgCl/KCl (3.0 M) for the various concentrations of hydrazine in 0.1 M PBS (pH 7.0) (Fig. 4). For an electroactive material (hydrazine in this case) with a diffusion coefficient of D, the current observed for the electrochemical reaction at the mass transport limited condition is described by the Cottrell equation (Bard and Faulkner 2001). I ¼ nFAD1=2 C b π−1=2 t −1=2
ð1Þ
where D and C b are the diffusion coefficient (cm2 s−1) and the bulk concentration (mol cm−3), respectively. Experimental plots of I vs. t−1/2 were employed, with the best fits for different concentrations of hydrazine (Fig. 4a). The slopes of the resulting straight lines were then plotted vs. hydrazine concentration (Fig. 4b). From the resulting slope and Cottrell equation, the mean value of D was found to be 1.07×10−6 cm2 s−1.
122
Environ Monit Assess (2015) 187:122
Page 6 of 10
Chronoamperometry can also be employed to evaluate the catalytic rate constant, k, for the reaction between hydrazine and the 3,4′-AAZCPE according to the method described by Galus (Galus 1976): h i I C = I L ¼ γ 1=2 π1=2 er f γ 1=2 þ expð−γ Þ=γ 1=2
ð2Þ
where IC is the catalytic current of hydrazine at the 3,4′AAZCPE, IL is the limited current in the absence of hydrazine, and γ=kCbt is the argument of the error function (Cb is the bulk concentration of hydrazine). In cases where γ exceeds the value of 2, the error function is almost equal to 1 and therefore, the above equation can be shortened to: I C =I L ¼ π1=2 γ 1=2 ¼ π1=2 ðkC b t Þ1=2
ð3Þ
where t is the time elapsed. The above equation can be used to calculate the rate constant, k, of the catalytic process from the slope of IC/IL vs. t1/2 at a given hydrazine concentration. From the values of the slopes (Fig. 4c), the average value of k was found to be 1.5×10 3 M−1 s−1. Fig. 4 Chronoamperograms obtained at 3,4′-AAZCPE in 0.1 M PBS (pH 7.0) for different concentrations of hydrazine. The numbers 1–5 correspond to 0.0, 0.1, 0.3, 0.7, and 1.0 mM of hydrazine. Insets, (a) plots of I vs. t−1/2 obtained from chronoamperograms 2–5. (b) Plot of the slope of the straight lines against hydrazine concentration. (c) Dependence of Ic/Il on t1/2 derived from the data of chronoamperograms 1–5
Calibration plot and limit of detection The electrocatalytic peak current of hydrazine oxidation at the surface of the 3,4′-AAZCPE can be used for determination of hydrazine in solution. Therefore, square wave voltammetry (SWV) experiments were performed using modified electrode in 0.1 M PBS (pH 7.0) containing various concentration of hydrazine (Fig. 5). The plot of peak current vs. hydrazine concentration consisted of two linear segments with slopes of 3.992 and 1.160 μA μM−1 in the concentration ranges of 2.5× 10−8 to 7.5×10−6 M and 7.5 ×10−6 to 5.0× 10−5 M, respectively. The difference in the slopes for the calibration curves is due to the different activity of the electrode surface with low and high concentrations of the analyte. In the lower hydrazine concentration, due to a high number of active sites (in relation to the total number of the analyte molecules), the slope of the first calibration curve is high. While in the higher hydrazine concentration, due to decreasing active sites (in relation to the total number of analyte molecules, mainly at the surface of the electrode), the slope of the second calibration decreased too.
Environ Monit Assess (2015) 187:122
Page 7 of 10 122
Fig. 5 SWVs of 3,4′-AAZCPE in 0.1 M PBS (pH 7.0) containing different concentrations of hydrazine. Numbers 1–10 correspond to 0.025, 0.05, 0.25, 0.5, 2.5, 7.5, 10.0, 20.0, 30.0, and 50.0 μM of hydrazine. Insets, the plots of the electrocatalytic peak current as a function of hydrazine concentration in the range of (a) 0.025–7.5 and (b) 7.5–50.0 μM
Also, the detection limit, Cm, of hydrazine was obtained using the following equation: C m ¼ 3sb =m
measurements of the blank solution. The detection limit (3σ) of hydrazine was found to be 14 nM.
ð4Þ Real sample analysis
In the above equation, m is the slope of the calibration plot (3.992 μA μM−1) in the first linear range (2.5×10−8 to 7.5×10−6 M), and sb is the standard deviation of the blank response which is obtained from 20 replicate
Table 1 The application of 3,4AAZCPE for determination of hydrazine in water samples (n=5)
Sample Drinking water
River water
ND not detected, R.S.D. relative standard deviation
In order to evaluate the analytical applicability of the proposed method, it was also applied to the determination of hydrazine in water samples. The results are listed
Spiked (μM) 0
Found (μM) ND
Recovery (%) –
R.S.D. (%) –
5.0
4.9
98.0
3.2
10.0
10.3
103.0
1.6
15.0
15.3
102.0
2.4
20.0
19.8
99.0
0
ND
–
2.1 –
2.5
2.6
104.0
7.5
7.4
98.7
1.9 3.4
12.5
12.6
100.8
2.6
17.5
17.1
97.7
2.9
122
Page 8 of 10
in Table 1. Satisfactory recovery of the experimental results was found for hydrazine. The reproducibility of the method was demonstrated by the mean relative standard deviation (R.S.D.).
Conclusions The 3,4′-AAZCPE was prepared and used for the investigation of the electrochemical behavior of hydrazine. Two pairs of well-defined redox peaks were obtained at the 3,4′-AAZCPE. The 3,4′-AAZCPE showed excellent electrocatalytic activity for the hydrazine. The SWV currents of hydrazine at 3,4′-AAZCPE increased linearly with the hydrazine concentration in the range from 2.5×10−8 to 5.0×10−5 M with a detection limit of 14 nM. Finally, this method was used for the determination of hydrazine in water samples. Acknowledgements The authors wish to thank Payame Noor University for support of this work.
References Adekunle, A. S., & Ozoemena, K. I. (2008). Insights into the electro-oxidation of hydrazine at single-walled carbonnanotube-modified edge-plane pyrolytic graphite electrodes electro-decorated with metal and metal oxide films. Journal of Solid State Electrochemistry, 12(10), 1325–1336. Afkhami, A., & Zarei, A. R. (2004). Simultaneous spectrophotometric determination of hydrazine and phenylhydrazine based on their condensation reactions with different aromatic aldehydes in micellar media using Hpoint standard addition method. Talanta, 62(3), 559–565. Amlathe, S., & Gupta, V. K. (1988). Spectrophotometric determination of trace amounts of hydrazine in polluted water. Analyst, 113(9), 1481–1483. Bard, A. J., & Faulkner, L. R. (2001). Electrochemical methods fundamentals and applications (2nd ed.). New York: Wiley. Beitollahi, H., & Ghorbani, F. (2013). Benzoylferrocene-modified carbon nanotubes paste electrode as a voltammetric sensor for determination of hydrochlorothiazide in pharmaceutical and biological samples. Ionics, 19(11), 1673–1679. Beitollahi, H., & Mostafavi, M. (2014). Nanostructured base electrochemical sensor for simultaneous quantification and voltammetric studies of levodopa and carbidopa in pharmaceutical products and biological samples. Electroanalysis, 26(5), 1090–1098. Beitollahi, H., & Sheikhshoaie, I. (2011). Electrocatalytic and simultaneous determination of isoproterenol, uric acid and folic acid at molybdenum (VI) complex-carbon nanotube paste electrode. Electrochimica Acta, 56(27), 10259–10263.
Environ Monit Assess (2015) 187:122 Beitollahi, H., Karimi-Maleh, H., & Khabazzadeh, H. (2008). Nanomolar and selective determination of epinephrine in the presence of norepinephrine using carbon paste electrode modified with carbon nanotubes and novel 2-(4-Oxo-3-phenyl-3,4dihydroquinazolinyl)- N′-phenyl-hydrazinecarbothioamide. Analytical Chemistry, 80(24), 9848–9851. Beitollahi, H., Raoof, J. B., & Hosseinzadeh, R. (2011). Application of a carbon-paste electrode modified with 2,7bis(ferrocenyl ethyl)fluoren-9-one and carbon nanotubes for voltammetric determination of levodopa in the presence of uric acid and folic acid. Electroanalysis, 23(8), 1934–1940. Beitollahi, H., Tajik, S., Karimi Maleh, H., & Hosseinzadeh, R. (2013). Application of a 1-benzyl-4-ferrocenyl-1H-[1,2,3]triazole/carbon nanotube modified glassy carbon electrode for voltammetric determination of hydrazine in water samples. Applied Organometalic Chemistry, 27(8), 444–450. Brahman, P. K., Dar, R. A., Tiwari, S., & Pitre, K. S. (2012). Voltammetric determination of anticancer drug flutamide in surfactant media at polymer film modified carbon paste electrode. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 396, 8–15. Budkuley, J. S. (1992). Determination of hydrazine and sulphite in the presence of one another. Microchimica Acta, 108(1–2), 103–105. Chitravathi, S., Kumara Swamy, B. E., Mamatha, G. P., & Sherigara, B. S. (2012). Electrochemical behavior of poly (naphthol green B)-film modified carbon paste electrode and its application for the determination of dopamine and uric acid. Journal of Electroanalytical Chemistry, 667, 66–75. Devnani, H., & Satsangee, S. P. (2013). Voltammetric trace determination of mercury using plant refuse modified carbon paste electrodes. Environmental Monitoring and Assessment, 185(11), 9333–9342. Ensafi, A. A., & Rezaei, B. (1998). Flow injection determination of hydrazine with fluorimetric detection. Talanta, 47(3), 645–649. Esfandiari Baghbamidi, S., Beitollahi, H., Mohammadi, S. Z., Tajik, S., Soltani-Nejad, S., & Soltani-Nejad, V. (2013). Nanostructure-based electrochemical sensor for the voltammetric determination of benserazide, uric acid, and folic acid. Chinese Journal of Catalysis, 34(10), 1869–1875. Evgen’yev, M. I., Garmonov, S. Y., Evgen’yeva, I. I., & Budnikov, H. C. (1995). Determination of hydrazine derivatives by flow-injection analysis with spectrophotometric detection. Talanta, 42(10), 1465–1469. Fonseca, J., Dohrn, R., & Peper, S. (2011). High-pressure fluid phase equilibria: experimental methods and systems investigated. Critical Reviews in Analytical Chemistry, 41, 282–313. Galus, Z. (1976). Fundamentals of electrochemical analysis. New York: Ellis Horwood. Geraldo, D. A., Togo, C. A., Limson, J., & Nyokong, T. (2008). Electrooxidation of hydrazine catalyzed by noncovalently functionalized single-walled carbon nanotubes with CoPc. Electrochimica Acta, 53(27), 8051–8057. Ghaedi, M., Naderi, S., Montazerozohori, M., Sahraei, R., Daneshfar, A., & Taghavimoghadam, N. (2012). Modified carbon paste electrodes for Cu(II) determination. Materials Science and Engineering C, 32(8), 2274–2279. Gojon, C., Dureault, B., Hovnanian, N., & Guizard, C. (1999). Optical chemical hydrazine sensor from hybrid organicinorganic materials. Journal of Sol-Gel Science and Technology, 14(2), 163–173.
Environ Monit Assess (2015) 187:122 Goyal, R. N., Gupta, V. K., & Bachheti, N. (2007). Fullerene-C60modified electrode as a sensitive voltammetric sensor for detection of nandrolone—an anabolic steroid used in doping. Analytica Chimica Acta, 597, 82–89. Goyal, R. N., Gupta, V. K., Bachheti, N., & Sharma, R. N. (2008). Electrochemical sensor for the determination of dopamine in presence of high concentration of ascorbic acid using a fullerene-C60 coated gold electrode. Electroanalysis, 20, 757–764. Guo, S. X., & Khoo, S. B. (1997). Formation of a mercury plated carbon paste electrode by electroreduction of a mercury(II) diethyldithiocarbamate modified carbon paste. Environmental Monitoring and Assessment, 44(1–3), 471–480. Gupta, V. K., Mangla, R., Khurana, U., & Kumar, P. (1999). Determination of uranyl ions using poly (vinyl chloride) based 4-tert-butylcalix [6] arene membrane sensor. Electroanalysis, 11, 573–576. Gupta, V. K., Prasad, R., Kumar, P., & Mangla, R. (2000). New nickel(II) selective potentiometric sensor based on 5,7,12,14tetramethyldibenzotetraazaannulene in a poly(vinyl chloride) matrix. Analytica Chimica Acta, 420, 19–27. Gupta, V. K., Chandra, S., & Mangla, R. (2002). Dicyclohexano- 18-crown-6 as active material in PVC matrix membrane for the fabrication of cadmium selective potentiometric sensor. Electrochimica Acta, 47, 1579–1586. Gupta, V. K., Jain, S., & Chandra, S. (2003). Chemical sensor for lanthanum(III) determination using aza-crown as ionophore in poly(vinyl chloride) matrix. Analytica Chimica Acta, 486, 199– 207. Gupta, V. K., Chandra, S., & Lang, H. (2005). A highly selective mercury electrode based on a diamine donor ligand. Talanta, 66, 575–580. Gupta, V. K., Jain, A. K., Kumar, P., Agarwal, S., & Maheshwari, G. (2006a). Chromium(III)-selective sensor based on triothymotide in PVC matrix. Sensors and Actuators B: Chemical, 113, 182–186. Gupta, V. K., Jain, A. K., Maheshwari, G., Lang, H., & Ishtaiwi, Z. (2006b). Copper(II)-selective potentiometric sensors based on porphyrins in PVC matrix. Sensors and Actuators B: Chemical, 117, 99–106. Gupta, V. K., Jain, A. K., & Kumar, P. (2006c). PVCbased membranes of N, N’-dibenzyl-1,4,10,13tetraoxa-7,16- diazacyclooctadecane as Pb(II)-selective sensor. Sensors and Actuators B: Chemical, 120, 259–265. Gupta, V. K., Singh, A. K., Mehtab, S., & Gupta, B. (2006d). A cobalt(II)-selective PVC membrane based on a Schiff base complex of N, N’-bis(salicylidene)-3,4-diaminotoluene. Analytica Chimica Acta, 566, 5–10. Gupta, V. K., Singh, A. K., Khayat, M. A. I., & Gupta, B. (2007). Neutral carriers based polymeric membrane electrodes for selective determination of mercury (II). Analytica Chimica Acta, 590, 81–90. Gupta, V. K., Jain, R., Radhapyari, K., Jadon, N., & Agarwal, S. (2011a). Voltammetric techniques for the assay of pharmaceuticals—a review. Analytical Biochemistry, 408, 179–196. Gupta, V. K., Nayak, A., Agarwal, S., & Singhal, B. (2011b). Recent advances on potentiometric membrane sensors for pharmaceutical analysis. Combinatorial Chemistry & High Throughput Screening, 14(4), 284–302.
Page 9 of 10 122 Gupta, V. K., Singh, L. P., Singh, R., Upadhyay, N., Kaur, S. R., & Sethi, B. (2012). A novel copper (II) selective sensor based on dimethyl 4, 4′ (o-phenylene) bis(3-thioallophanate) in PVC matrix. Journal of Molecular Liquids, 174, 11–16. Gupta, V. K., Sethi, B., Sharma, R. A., Agarwa, S., & Bharti, A. (2013). Mercury selective potentiometric sensor based on low rim functionalized thiacalix [4]-arene as a cationic receptor. Journal of Molecular Liquids, 177, 114–118. Hočevar, S. B., & Ogorevc, B. (2007). Preparation and characterization of carbon paste micro-electrode based on carbon nano-particles. Talanta, 74(3), 405–411. Jain, A. K., Gupta, V. K., Singh, L. P., & Khurana, U. (1997). Macrocycle based membrane sensors for the determination of cobalt(II) ions. Analyst, 122, 583–586. Jain, A. K., Gupta, V. K., Singh, L. P., & Raisoni, J. R. (2006). A comparative study of Pb2+ 11 sensors based on derivatized tetrapyrazole and calix[4]arene receptors. Electrochimica Acta, 51, 2547–2553. Jain, R., Gupta, V. K., Jadon, N., & Radhapyari, K. (2010). Voltammetric determination of cefixime in pharmaceuticals and biological fluids. Analytical Biochemistry, 407, 79–88. Jayasri, D., & Sriman, N. S. (2007). Amperometric determination of hydrazine at manganese hexacyanoferrate modified graphite–wax composite electrode. Journal of Hazardous Materials, 144(1–2), 348–354. Karimi-Maleh, H., Tahernejad-Javazmi, F., Ensafi, A. A., Moradi, R., Mallakpour, S., & Beitollahi, H. (2014). A high sensitive biosensor based on FePt/CNTs nanocomposite/N-(4-hydroxyphenyl)-3,5-dinitrobenzamide modified carbon paste electrode for simultaneous determination of glutathione and piroxicam. Biosensors and Bioelectronics, 60, 1–7. Kirchherr, H. (1993). Determination of hydrazine in human plasma by high-performance liquid chromatography. Journal of Chromatography B, 617(1), 157–162. Leakakos, T., & Shank, R. C. (1994). Hydrazine genotoxicity in the neonatal rat. Toxicology and Applied Pharmacology, 126(2), 295–300. Mahanthesha, K. R., Kumara Swamy, B. E., Chandra, U., Sharath Shankar, S., & Pai, K. V. (2012). Electrocatalytic oxidation of dopamine at murexide and TX-100 modified carbon paste electrode: a cyclic voltammetric study. Journal of Molecular Liquids, 172, 119–124. Mahmoudi Moghaddam, H., Beitollahi, H., Tajik, S., Malakootian, M., & Karimi Maleh, H. (2014). Simultaneous determination of hydroxylamine and phenol using a nanostructure-based electrochemical sensor. Environmental Monitoring and Assessment, 186(11), 7431–7441. Mashhadizadeh, M. H., & Shamsipur, M. (1997). Silver(I)-selective membrane electrode based on hexathia-18-crown-6. Electroanalysis, 9, 478–480. Mazloum-Ardakani, M., Rajabi, H., Mirjalili, B. B. F., Beitollahi, H., & Akbari, A. (2010). Nanomolar determination of hydrazine by TiO2 nanoparticles modified carbon paste electrode. Journal of Solid State Electrochemistry, 14(12), 2285–2292. Mazloum-Ardakani, M., Taleat, Z., Beitollahi, H., & Naeimi, H. (2011). Nanomolar concentrations determination of hydrazine by a modified carbon paste electrode incorporating TiO2 nanoparticles. Nanoscale, 3(4), 1683–1689. Mo, J.-W., Ogorevc, B., Zhang, X., & Pihlar, B. (2000). Cobalt and copper hexacyanoferrate modified carbon fiber
122
Page 10 of 10
microelectrode as an all-solid potentiometric microsensor for hydrazine. Electroanalysis, 12(1), 48–54. Mokhtari, A., Karimi-Maleh, H., Ensafi, A. A., & Beitollahi, H. (2012). Application of modified multiwall carbon nanotubes paste electrode for simultaneous voltammetric determination of morphine and diclofenac in biological and pharmaceutical samples. Sensors and Actuators B: Chemical, 169, 96–105. Molaakbari, E., Mostafavi, A., & Beitollahi, H. (2014). First electrochemical report for simultaneous determination of norepinephrine, tyrosine and nicotine using a nanostructure based sensor. Electroanalysis, 26, 2252–2260. Mori, M., Tanaka, K., Xu, Q., Ikedo, M., Taoda, H., & Hu, W. (2004). Highly sensitive determination of hydrazine by ionexclusion chromatography with ion-exchange enhancement of conductivity detection. Journal of Chromatography A, 1039(1–2), 135–139. Moyo, M., Okonkwo, J. O., & Agyei, N. M. (2014). Maize tasselmodified carbon paste electrode for voltammetric determination of Cu(II). Environmental Monitoring and Assessment, 186(8), 4807–4817. Oztekin, Y., Tok, M., Bilici, E., Mikoliunaite, L., Yazicigil, Z., Ramanaviciene, A., & Ramanavicius, A. (2012). Copper nanoparticle modified carbon electrode for determination of dopamine. Electrochimica Acta, 76, 201–207. Pinter, J. S., Brown, K. L., Young, P. A. D., & Peaslee, G. F. (2007). Amperometric detection of hydrazine by cyclic voltammetry and flow injection analysis using ruthenium modified glassy carbon electrodes. Talanta, 71(3), 1219–1225. P r a s a d , R . , G u p t a , V. K . , & K u m a r, A . ( 2 0 0 4 ) . Metallotetraazaporphyrin based anion sensors: regulation of sensor characteristics through central metal ion coordination. Analytica Chimica Acta, 508, 61–70. Raoof, J. B., Ojani, R., Beitollahi, H., & Hosseinzadeh, R. (2006). Electrocatalytic oxidation and highly selective voltammetric determination of l-cysteine at the surface of a1-[4-(ferrocenyl ethynyl)phenyl]-1-ethanone modified carbon paste electrode. Analytical Sciences, 22(9), 1213–1220. Safavi, A., & Karimi, M. A. (2002). Flow injection chemiluminescence determination of hydrazine by oxidation with chlorinated isocyanurates. Talanta, 58(4), 785–792. Sax, N. I. (1980). Dangerous properties of industrial materials (4th ed., p. 814). New York: van Nostrand-Reinhold. Seifart, H. I., Gent, W. L., Parkin, D. P., van Jaarsveld, P. P., & Donald, P. R. (1995). High-performance liquid
Environ Monit Assess (2015) 187:122 chromatographic determination of isoniazid, acetylisoniazid and hydrazine in biological fluids. Journal of Chromatography B, 674(2), 269–275. Serpi, C., Kovatsi, L., & Girousi, S. (2014). Electroanalytical quantification of total dsDNA extracted from human sample using, an ionic liquid modified, carbon nanotubes paste electrode. Analytica Chimica Acta, 812, 26–32. Shustina, R., & Lesser, J. H. (1991). Liquid chromatographic determination of hydrazine, carbohydrazide and thiocarbohydrazide in aqueous solutions. Journal of Chromatography A, 464(28), 208–212. Siangproh, W., Chailapakul, O., Laocharoensuk, R., & Wang, J. (2005). Microchip capillary electrophoresis/electrochemical detection of hydrazine compounds at a cobalt phthalocyanine modified electrochemical detector. Talanta, 67(5), 903–907. Srivastava, S. K., Gupta, V. K., & Jain, S. (1996). PVC-based 2,2, 2-cryptand sensor for zinc ions. Analytical Chemistry, 68, 1272–1275. Sun, W., Wang, Y., Gong, S., Cheng, Y., Shi, F., & Sun, Z. (2013). Application of poly(acridine orange) and graphene modified carbon/ionic liquid paste electrode for the sensitive electrochemical detection of rutin. Electrochimica Acta, 109, 298– 304. Valle, M. A., Gacitua, M., Diaz, F. R., Armijo, F., & Soto, J. P. (2012). Electro-synthesis and characterization of polythiophene nano-wires/platinum nano-particles composite electrodes. Study of formic acid electro-catalytic oxidation. Electrochimica Acta, 71, 277–282. Wang, Y., Wu, Y., Xie, J., & Hu, X. (2013). Metal–organic framework modified carbon paste electrode for lead sensor. Sensors and Actuators B: Chemical, 177, 1161–1166. Yu, X., Chen, Y., Chang, Z. L., Tang, F., & Wu, X. (2013). βCyclodextrin non-covalently modified ionic liquid-based carbon paste electrode as a novel voltammetric sensor for specific detection of bisphenol A. Sensors and Actuators B: Chemical, 186, 648–656. Zheng, H., & Shank, R. C. (1996). Changes in methyl-sensitive restriction sites of liver DNA from hamsters chronically exposed to hydrazine sulfate. Carcinogenesis, 17(12), 2711–2717. Zhike, H., Xinglian, L., Qingyao, L., Hongwu, T., Ximao, Y., Hui, C., & Yune, Z. (1996). Automatic injection analysis with chemiluminescence: detection determination of hydrazine. Microchemical Journal, 53(3), 356–360.
