VOL.

XXXI

NO.

FIELD

4

THE

DESORPTION

SPECTROMETRY

OF

JOURNAL

MASS NUCLEOSIDE

ANTIBIOTICS

KAZUTAKA FUKUSHIMA and TADASHI ARAI Department of Antibiotics, Research Institute for Chemobiodynamics, Chiba University, Inohana, Chiba, Japan (Received for publication January 17, 1978)

The mass spectra of thirteen nucleoside antibiotics of various kinds have been studied using the field desorption method. All antibiotics yielded intensive molecular or quasimolecular ions (QM+) at emitter currents above the best anode temperature. Fragment ions which were characteristic to chemical structures were observed. Antibiotics: All antibiotics were of reagent

Cordycepin(1) MW251 15 n4: 135(452) 251(1000; 252(387)

Formycin 8 (6) MW 268 15 mA: 268(941) 269(1000)

Puromycin(11) MW471 15 TA: 471(1000) 472(656)

Cytosine-arabinoside(2) MW243 16 mA: 111(243) 112(171) 244(1000) 245(152)

Showdomycin(7) 11W229 14 mA: 229(1000) 230(156)

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grade and were used without further purification. They are cordycepin (1), cytosine-arabinoside(2), tubercidin(3), toyocamycin(4), formycin(5), formycin B (6), showdomycin (7), oxazinomycin (8), nucleocidin (9), gougerotin (10), puromycin (11), blasticidin S (12) and polyoxin A (13). Mass spectrometry: The f.d.m.s. were obtained with a double-focusing JEOL O1SG-2 instrument equipped with a combined e.i.f.i.f.d. ion source and a JMA 2000 data analysis system. Sample loading to the emitter was by glass capillary technique using aqueous solutions of samples. Instrument conditions included: accelerating voltage of + 10 KV; cathode voltage of -2 KV. The antibiotics examined are presented with the emitter currents at which the spectra were recorded followed by m/e values and relative intensities.

Tubercidin(3) MW266 15 mA:266(1020) 267(677)

Oxazinomycin(8) MW245 16 ,nA: 245(577) 246(1000)

Toyocamycin(4) MW291 16 :nA: 159(273) 291(1000) 292(90)

liucleocidin(9) MW364 17 mA: 135(161) 365(1000) 366)24E)

Blasticidin S (12) MW422 17 mA: 111(1000), 171(296), 312(630), 422(667) 19 mA: 111(1000), 112(764), 171(909), 251(800), 324(473)

Formycin(5) MW267 14 mA: 267(844) 268(1000)

Gougerotin(10) MW443 17 mA: 444(1000) 445(210) 466(512) 467(163)

Po7yoxin A (13) MW616 17 mA: 132(625) 617(1000) 612(142)

378

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JOURNAL

From these data, the following remarks can be made. The molecular ion or quasitnolecular ion, (M + H)+, was usually present as base peak in the spectra of the antibiotics of this group. In C-nucleoside antibiotics, only M+ or (M+H)+ was observed at best anode temperature. The fragment ions due to the protonated base moiety of the molecules were observed as the most notable in many spectra. Aggregated ions with metallic ions such as Na+ or K+ often occurred in the various compounds, e.g. nucleosides'), nucleotides', and sugars". In gougerotin (10), QM+ aggregated with Na+ (which might stem either from the sample or the solvents) was observed at in/e 466. The f.d.m.s. appears to have a great potential for the structural study of nucleoside compounds, especially for the determination of their molecular weights. In c.i. mass spectrometry of similar corn-

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ANTIBIOTICS

pounds

with

probes,

HUNT et al.4) came

field

desorption

APR.

1978

as

solid

emitters

to similar

conclusions.

References

1)

SCHULTEN, H. R. & H. D. BECKY: lution field Nucleosides

2)

trom. 7: 861 - 867, 1973 BUDZIKIEwlcz, H. & M. ionization

High

reso-

desorption mass spectrometry. 1: and nucleotides. Org. Mass Spec-

mass

spectrometry:

LINSCHEID: Field

Field desorp-

tion spectra of nucleotides-Experimental problems. Biomed. Mass Spectrom. 4: 103-106, 1977 3)

PROME, J.-C. & G. Puzo: Field desorption mass spectrometry of oligosaccharides in the presence Spectrom.

4)

of metallic 12: 28-32,

salts. 1977

Biomed.

Mass

HUNT, D. F.; J. SHABANOWITZ & F. K. Boiz: Chemical ionization mass spectrometry of salts and thermally tion emitters 49:

labile organics with field desorpas solids probes. Anal. Chem.

1160 - 1163, 1977

Field desorption mass spectrometry of nucleoside antibiotics.

VOL. XXXI NO. FIELD 4 THE DESORPTION SPECTROMETRY OF JOURNAL MASS NUCLEOSIDE ANTIBIOTICS KAZUTAKA FUKUSHIMA and TADASHI ARAI Department of...
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