The Use of Solid-Phase Microextraction in Conjunction with a Benchtop Quadrupole Mass Spectrometer for the Analysis of Volatile Organic Compounds in Human Blood at the Low Parts-Per-Trillion Level

The analysis of volatile organic compounds (VOCs) in whole human blood at the low parts-per-trillion level has until recently required the use of a high-resolution mass spectrometer to obtain the specificity and detection limits required for epidemiological studies of VOC exposure in the general public. Because of the expense and expertise required to operate and maintain a high-resolution instrument, the applicability of this method has been limited. These limitations are overcome in a new method using automated headspace solid-phase microextraction (SPME) in conjunction with a gas chromatograph and a benchtop quadrupole mass spectrometer. A combination of SPME and multiple single-ion monitoring minimizes the interferences and chemical noise associated with whole blood samples. This method permits the analysis of 10 VOCs in human blood while simplifying the sample preparation and reducing the possible exposure of the analyst to blood aerosols. Twelve samples can be run successively in a fully automated mode, thus eliminating the need for operator attention. Detection limits are below 50 ppt (pg/mL) for a majority of the VOCs tested with a 5-mL sample.