Analysis of silyl derivatives of methylphosphonic acid esters by the method of gas chromatography/mass spectrometry with atmospheric pressure photoionization

T11N2

Yu.S. Yashin, I.A. Revel’sky, I.N. Tikhonova
M.V. Lomonosov Moscow State University, Chemistry Department

Using trimethylsilyl (TMS) and  tert-butyldimethylsilyl (TBDMS) derivatives of methylphosphonic acid and methylphosphonic acid  esters, a comparative study of two ionization methods, namely, atmospheric pressure photoionization (APPhI) and photochemical  ionization (APPhCI), in gas chromatography/mass spectrometry has been performed. It has been shown that in case of APPhI mass spectra of TMS and TBDMS derivatives consisted of only peaks corresponding to [М+73]+ and [М+115]+ (or [M+Si(Me)3]+ and [M+Si(t Bu)(Me)2]+ respectively, where M is molecular mass of respective TMS or TBDMS derivative of methylphosphonic ester). APPhCI mass spectra recorded in the presence of acetone as reagent substance consisted of only [MH]+ and [MMAH]+ ion peaks (MA – acetone molecule). Corresponding detection limits for silylated derivatives in case of APPhI and APPhC were 30–125 pg and 1.1–23 pg respectively (depending on the analyte).

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