Abstract-Several reagent gases and mixed reagent gases for high pressure ion-molecule reaction ionization of samples have been investigated for use in gas chromatography-mass spectrometry analyses. The common g.c. carrier gases and their mixtures with other gases suchas isobutane, ammonia. tetramethylsilane, hexafluoroacetone and nitric oxide, were studied. These reagents were used to enhance the molecular ion intensity and to simpiify the spectra of steroidal alcohols and the trimethylsilyl ethers of biologically important compounds.

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CHs's on tertiary C's), 1.95 (s, 1, H on C with -NHC02Et). The two methyl groups on each of the four secondary insertion products should each appear as a doublet. The singlet listed at 0.87 is the envelope of these closely spaced, unresolved doublets. The primary insertion product was not present in sufficient quantity for analysis and assignment was based on retention time and selectivity data.The stereospecificty and selectivity were then calculated from the peak areas in the usual manner.The absolute yield was determined by using acetophenone as an external standard. Total moles of insertion product was then calculated from the area/mol for acetophenone using the calibration factor of 0.78 for the products relative to acetophenone. It was assumed that all the insertion products have the same detector sensitivity.

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.

In the 70 eV electron impact mass spectra of a series of alkyldiphenylphosphie oxides (R+,PO, R = Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, neopentyl, n-decyl), molecular ions of low abundance are observed and [M + H]+ ions are formed to a small extent at high sample pressures. The major ions include [&PO]+, [&POHI+; [&CH,PO]+ and [+,CH,POH]+ which are formed by rearrangement and cleavage processes. The chemical ionization mass spectra obtained with methane and isobutane reagents consist of [M+H]+ ions. The proton f f i i t y of R&PO was found to be 219 f 2.5 kcal mol-'.