Techniques in gas chromatography/chemical ionization mass spectrometry

Hatch, Frank; Munson, Burnaby

doi:10.1021/ac50009a050

Cited by 19 publications

(17 citation statements)

References 29 publications

(37 reference statements)

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“…The modifications for CI operation have been described previously. 30,31 The electron energy for the low voltage experiments was calibrated with the appearance energy of the [CH,]' ion in methane. *' Different conditions were used for different experiments, but the spectra for a given set of stereoisomers were obtained under conditions as nearly identical as possible for each type of experiment.…”

Section: Methodsmentioning

confidence: 99%

Stereochemical effects in the mass spectra of 2‐hydroxy‐, 5‐hydroxy‐ and 2,5‐dihydroxyprotoadamantanes

Munson

Jelus

Hatch

et al. 1980

Org. Mass Spectrom.

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Electron ionization and methane and isobutane chemical ionization mass spectra have been obtained for the four configurationally isomeric 2,5-protoadamantanediols and the corresponding model monoalcohols. Although the electron impact (both 70 and 15 eV) and methane chemical ionization mass spectra of the 2,5-protoadamantanediols are distinct, the variations are not large and in general they are difficult to rationalize in terms of specific structural features. In contrast, the isobutane chemical ionization mass spectra of these diols show significant differences which can easily he correlated with sterochemical orientations of the substituents.

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Section: Methodsmentioning

confidence: 99%

Stereochemical effects in the mass spectra of 2‐hydroxy‐, 5‐hydroxy‐ and 2,5‐dihydroxyprotoadamantanes

Munson

Jelus

Hatch

et al. 1980

Org. Mass Spectrom.

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“…We wish to report the relatively simple operating and optimization procedures for obtaining in-beam/CI spectra which are comparable to spectra obtained by FD/CI. EXPERIMENTAL The experiments were performed with a duPont 21-llOB mass spectrometer which has been modified for high pressure operation (11). In addition, a data acquisition system has been added to the instrument to allow rapid scanning (4.5 s for the mass range of 28 to 600) of spectra, every 6.5 s.…”

Section: Literature Citedmentioning

confidence: 99%

Surface chemical ionization mass spectrometry

Hansen¹,

Munson²

1978

Anal. Chem.

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1'0DC129 Vlcm Torr %TIC 3 0 30 (155.,,,,,'" 0 1 0 3 Torr % T I C 2 0 '0 4 0 60 8 3 803 2 0 ETHYL BUTYRATE 2 o L _ _ . d 1 0 43 60 8 0 1 0 3 1 2 0 "ROPYL PRCP OluA-E Flgure 3.Water CI spectra of ethyl butyrate and propyl propionate obtained in the drift-tube CI source with water reagent gas at 110 OC and 0.103 Torr. The drift field strength was 129 Vkm-Torr, sufficient to produce substantial amounts of fragmentation characteristic of these two structural isomers preferential solvation of the product ion favors formation of RCOOH2+-OH2 from (RCOOR')H+.OH, over formation of RCOOH2+ from (RCOOH')H+. Inasmuch as the origins and analytical utility of all of the various ions observed in the CI spectra of esters have been discussed extensively in previous work (6,8,14), there is no ease of identifying esters from their water CI spectra at high E / P in the drift tube source, Figure 3 compares the spectra of ethyl butyrate and propyl propionate at 129 V/cm-Torr. The MH+ ions at m / e 117 are present for both esters, but none of the other peaks are identical. The fragment ions in ethyl butyrate are R+ ( m / e 43), RCO' ( m / e 711, RCOOH2+ ( m / e 89), and RCOOH2+.0H2 ( m / e 107), while the fragment ions \ need to repeat that information here. As an example of the The use of "in-beam" sample introduction to obtain chemical ionization (CI) mass spectra of thermally labile compounds and salts of low volatilHy is descrlbed. Samples are introduced on the surface of Teflon tubing and the effects of changing the sample position in the source are shown. The time and temperature dependence of some CI mass spectra are shown.

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“…Few investigations of this kind have been reported. Experiments with fish have shown that uptake and accumulation take place directly from water and from food, and symptoms of toxicity have been observed (2)(3)(4)(5)(6). Determination of small amounts of CP is particularly difficult.…”

Section: Central Institute For Industrial Research (Ciir) Po Box 3mentioning

confidence: 99%

Matrix effects in quantitation and identification by chemical ionization mass spectrometry

Kallos¹,

Caldecourt²,

Tou³

1982

Anal. Chem.

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1313 Shea, K. J.; Gobeille, R.; Brarnblett, J.; Thompson, E. J . Am. Chem. Wolf, J. F.; Devlin, J. I.., 111; Taft, R. W.; Wolfsberg, M.; Hehre, W. J. J . Am. Chem. SOC. 1976, 98, 287. Wolf, J. F.; Devlln, J. l.., 111; DeFrees, D. J.; Taft, R. W.; Hehre, W. J. J . Am. Chem. SOC. 1976, 98, 5097. Sunko, D. E.; Szeleand, I.; Hehre, W. J. J . Am. Chem. SOC. 1977, 99, 5000. DeFrees, D. J.; Taagepera, M.; Levi, B. A.; Pollack, S. K.; Summerhays, K. D.; Taft, R. VV.; Wolfsberg, M.; Hehre, W. J.A technlque has been developed wlth modlflcatlon of a quadrupole mass spectrometer allowing both the reactant and product Ion currents ta, be acquired simultaneously. This method allows observatlon of the changes In fragmentatlon patterns for structure identlflcatlon and/or the response sensltlvlty of an Ion for quantltatlon. For certaln matrlx compounds the effect was found to be slgnlflcanl even though the normal CI/MS condltloins are reallzed. Quantltatlon by sollds probe, when uslng methane as reagent gas, may be more dlfflcult due to the nonreproduclble desorption of water from the probe. The matrlx effect can be mlnlmlzed when softer

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Techniques in gas chromatography/chemical ionization mass spectrometry

Cited by 19 publications

References 29 publications

Stereochemical effects in the mass spectra of 2‐hydroxy‐, 5‐hydroxy‐ and 2,5‐dihydroxyprotoadamantanes

Stereochemical effects in the mass spectra of 2‐hydroxy‐, 5‐hydroxy‐ and 2,5‐dihydroxyprotoadamantanes

Surface chemical ionization mass spectrometry

Matrix effects in quantitation and identification by chemical ionization mass spectrometry

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