Tandem Mass Spectrometric Analysis (MS/MS) of Jet Fuels. Part 1. Experimental Procedures and Qualitative Data Analysis

摘要

A fast, direct mass spectrometry (MS) determination of hydrocarbon classes in jet fuels is presented. A novel inlet technique using 0.1 mm i.d. micropipet glass capillaries for sampling the liquid fuels and reproducibly placing the 10 to 20 microgram samples in the MS vacuum for analysis is demonstrated. Low voltage electron ionization is shown to produce molecular ion series characteristic of alkyl substituted naphthalenes, tetralins, and decalins. Structurally specific fragment ions for several hydrocarbons, as determined by gas chromatography - mass spectrometry, are used to help identify compound classes by tandem mass spectrometry (MS/MS). As discussed, MS/MS can add a dimension of separation to overlapping molecular ion series while maintaining the greater speed of direct MS over GC/MS. In addition, multivariate statistical analysis is demonstrated to be powerful method for comparison of MS spectra from complex jet fuels to chemical class standards.