A novel method for the rapid screening of degradation products derived from nerve agents by matrix-assisted laser desorption ionization time-of-flight mass spectrometry is described. Five standard products were selected as model compounds, including isopropyl methylphosphonic acid (IMPA), pinacolyl methylphosphonic acid (PMPA), ethyl methylphosphonic acid (EMPA), isobutyl methylphosphonic acid (i-BuMPA), and cyclohexyl methylphosphonic acid (CHMPA), which are degradation products of Sarin (GB), Soman (GD), VX, Russian VX (RVX), and GF, respectively. For comparison, CHCA (alpha-cyano-4-hydroxycinnamic acid) and DCCA (7-(diethylamino)coumarin-3-carboxylic acid) were used as the MALDI-matrix when the third harmonic generation (355 nm) of a Nd:YAG laser and a hydrogen Raman laser (multifrequency laser) were used, respectively. The method permitted the five nerve agent degradation products to be screened rapidly and successfully, suggesting that it has the potential for use as a routine monitoring tool.

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The optimal conditions for the separation and detection of a mixture of 18 phenethylamine/tryptamine derivatives were determined, using liquid chromatography/UV-absorption (LC/UV) and liquid chromatography/electrospray ionization mass spectrometry (LC/ESI MS) methods, respectively. Complete separation could be achieved within ~25 min using gradient elution (A, 0.1% formic acid aqueous solution/pH 2.5; B, acetonitrile). The limit of detection (LOD at S/N = 3) obtained by LC/UV-absorption (absorption wavelength, 280 nm) was in the range from 0.3 to 3 mg/mL. In contrast, when the LC/ESI MS method was used, the LODs for primary, secondary and tertiary amines were in the ranges 0.1 -3.0, 0.1 -0.2, and 0.05 -1.8 mg/mL, respectively. The lower LOD obtained for a tertiary amine can be attributed to the fact that its ionization efficiency (during the ESI process) is better than the others. In order to improve the LOD of a primary/secondary amine, a derivatization procedure was used in which the chemical structure was altered to a secondary/tertiary amine, via a reaction with acetic anhydride. As a result, the LODs for primary/secondary amines could be significantly improved. The characteristic mass fragmentations of the 18 phenethylamine/tryptamine derivatives, as well as the products of the reaction with acetic anhydride, were investigated, and the data were reported. A urine sample was obtained by spiking urine from a volunteer with the 18 derivatives, and after liquid-liquid extraction the sample was examined by LC/UV and LC/ESI MS, respectively. The extraction procedures used for the urine sample and the experimental conditions for the separation and detection were optimized.