3117
J. Sep. Sci. 2014, 37, 3117–3124
Saeid Khodadoust1 Mohammad Sharif Talebianpoor1 Mehrorang Ghaedi2 1 Medicinal
plants Research Center, Yasuj University of Medical Science, Yasuj, Iran 2 Department of chemistry, Yasouj University, Yasouj, Iran Received July 28, 2014 Revised August 28, 2014 Accepted July 31, 2014
Research Article
Application of an optimized dispersive nanomaterial ultrasound-assisted microextraction method for preconcentration of carbofuran and propoxur and their determination by high-performance liquid chromatography with UV detection An extraction method based on dispersive nanomaterial ultrasound-assisted microextraction was used for the preconcentration of carbofuran and propoxur insecticides in water samples prior to high-performance liquid chromatography with UV detection. ZnS:Ni nanoparticles were synthesized based on the reaction of the mixture of zinc acetate and nickel acetate with thioacetamide in aqueous media and then loaded on activated carbon (ZnS:Ni-AC). Different methods were used for recognizing the properties of ZnS:Ni-AC and then this nanomaterial was used for extraction of carbamate insecticide as new adsorbent. The influence of variables on the extraction method (such as amount of adsorbent (mg: NiZnS-AC), pH and ionic strength of sample solution, vortex and ultrasonic time (min), ultrasound temperature and desorption volume (mL) was investigated by a screening 27–4 Plackett–Burman design. Then the significant variables were optimized by using a central composite design combined with a desirability function. At optimum conditions, this method had linear response >0.0060– 10 g/mL with detection limit 0.0015 g/mL and relative standard deviations 20–80⬚. The morphology and size distribution of the ZnS:Ni nanoparticles were determined by TEM (JEM100CX TEM, Tokyo, Japan) at an operating voltage of 80 kV. The shape and surface morphology of the ZnS:Ni nanoparticles were investigated by a field-emission scanning electron microscope (FESEM) (Hitachi S4160, Japan) under an acceleration voltage of 15 kV. For FESEM, it is necessary to coat the ZnS:Ni nanoparticles by gold, which was carried out by Auto Fine Coater (JFC-1300, JEOL). The atomic composition of the ZnS:Ni nanoparticles was analyzed by energy-dispersive
www.jss-journal.com
J. Sep. Sci. 2014, 37, 3117–3124
X-ray spectroscopy using Oxford INCA II energy solid-state detector.
2.3 Equipment and software The chromatographic measurements were carried out with Agilent Technologies (Wilmington, DE, USA) 1100 HPLC system equipped with Microvacuum Degasser (model G1379A), Quaternary Pump (model G1311A), Series Multiple Wavelength Detector (model G13658: was set at 220 nm), and a Zorbax SB-C18 (150 × 4.6 mm, 5 m; Agilent Technologies) column. The chromatographic calculations were performed using Chemstation data handling system. Determination of carbofuran and propoxur was performed at the optimum separation condition by HPLC with isocratic binary mobile phase consisting of acetonitrile/water (30:70, v/v) with flow rate of 1 mL/min. Ultrasonic device (Tecno-Gaz, 60 Hz, 130 W, Parma, Italy) was equipped with a digital timer and temperature controller. An InoLab pH 730 (Germany) digital pH meter was employed for pH measurements. The morphology and dimensions of the adsorbent were determined by TEM. FTIR spectroscopy of the adsorbent was done using an FTIR spectrophotometer (Model: FT-IR JASCO 460 Plus). Spectra obtained in the range of 400–4000 cm−1 were analyzed. The Statistica statistical package software version 7.0 (Stat Soft, Tulsa, OK, USA) was used for experimental design analysis and subsequent regressional analysis of the experimental data. Statistical analysis of the model was performed to evaluate the analysis of variance (ANOVA). The quality of the polynomial model equation was judged statistically by the coefficient of determination R2 , and its statistical significance was determined by an F-test. P-values
J. Sep. Sci. 2014, 37, 3117–3124
Saeid Khodadoust1 Mohammad Sharif Talebianpoor1 Mehrorang Ghaedi2 1 Medicinal
plants Research Center, Yasuj University of Medical Science, Yasuj, Iran 2 Department of chemistry, Yasouj University, Yasouj, Iran Received July 28, 2014 Revised August 28, 2014 Accepted July 31, 2014
Research Article
Application of an optimized dispersive nanomaterial ultrasound-assisted microextraction method for preconcentration of carbofuran and propoxur and their determination by high-performance liquid chromatography with UV detection An extraction method based on dispersive nanomaterial ultrasound-assisted microextraction was used for the preconcentration of carbofuran and propoxur insecticides in water samples prior to high-performance liquid chromatography with UV detection. ZnS:Ni nanoparticles were synthesized based on the reaction of the mixture of zinc acetate and nickel acetate with thioacetamide in aqueous media and then loaded on activated carbon (ZnS:Ni-AC). Different methods were used for recognizing the properties of ZnS:Ni-AC and then this nanomaterial was used for extraction of carbamate insecticide as new adsorbent. The influence of variables on the extraction method (such as amount of adsorbent (mg: NiZnS-AC), pH and ionic strength of sample solution, vortex and ultrasonic time (min), ultrasound temperature and desorption volume (mL) was investigated by a screening 27–4 Plackett–Burman design. Then the significant variables were optimized by using a central composite design combined with a desirability function. At optimum conditions, this method had linear response >0.0060– 10 g/mL with detection limit 0.0015 g/mL and relative standard deviations 20–80⬚. The morphology and size distribution of the ZnS:Ni nanoparticles were determined by TEM (JEM100CX TEM, Tokyo, Japan) at an operating voltage of 80 kV. The shape and surface morphology of the ZnS:Ni nanoparticles were investigated by a field-emission scanning electron microscope (FESEM) (Hitachi S4160, Japan) under an acceleration voltage of 15 kV. For FESEM, it is necessary to coat the ZnS:Ni nanoparticles by gold, which was carried out by Auto Fine Coater (JFC-1300, JEOL). The atomic composition of the ZnS:Ni nanoparticles was analyzed by energy-dispersive
www.jss-journal.com
J. Sep. Sci. 2014, 37, 3117–3124
X-ray spectroscopy using Oxford INCA II energy solid-state detector.
2.3 Equipment and software The chromatographic measurements were carried out with Agilent Technologies (Wilmington, DE, USA) 1100 HPLC system equipped with Microvacuum Degasser (model G1379A), Quaternary Pump (model G1311A), Series Multiple Wavelength Detector (model G13658: was set at 220 nm), and a Zorbax SB-C18 (150 × 4.6 mm, 5 m; Agilent Technologies) column. The chromatographic calculations were performed using Chemstation data handling system. Determination of carbofuran and propoxur was performed at the optimum separation condition by HPLC with isocratic binary mobile phase consisting of acetonitrile/water (30:70, v/v) with flow rate of 1 mL/min. Ultrasonic device (Tecno-Gaz, 60 Hz, 130 W, Parma, Italy) was equipped with a digital timer and temperature controller. An InoLab pH 730 (Germany) digital pH meter was employed for pH measurements. The morphology and dimensions of the adsorbent were determined by TEM. FTIR spectroscopy of the adsorbent was done using an FTIR spectrophotometer (Model: FT-IR JASCO 460 Plus). Spectra obtained in the range of 400–4000 cm−1 were analyzed. The Statistica statistical package software version 7.0 (Stat Soft, Tulsa, OK, USA) was used for experimental design analysis and subsequent regressional analysis of the experimental data. Statistical analysis of the model was performed to evaluate the analysis of variance (ANOVA). The quality of the polynomial model equation was judged statistically by the coefficient of determination R2 , and its statistical significance was determined by an F-test. P-values
