Fatty acids in 42 types of saponified vegetable and animal oils were analyzed by electrospray ionization mass spectrometry (ESI-MS) for the development of their rapid discrimination. The compositions were compared with those analyzed by gas chromatography-mass spectrometry (GC-MS), a more conventional method used in the discrimination of fats and oils. Fatty acids extracted with 2-propanol were detected as deprotonated molecular ions ([M-H] -) in the ESI-MS spectra of the negative-ion mode. The composition obtained by ESI-MS corresponded to the data of the total ion chromatograms by GC-MS. The ESI-MS analysis discriminated the fats and oils within only one minute after starting the measurement. The detection limit for the analysis was approximately 10 -10 g as a sample amount analyzed for one minute. This result showed that the ESI-MS analysis discriminated the fats and oils much more rapidly and sensitively than the GC-MS analysis, which requires several tens of minutes and approximately 10 -9 g. Accordingly, the ESI-MS analysis was found to be suitable for a screening procedure for the discrimination of fats and oils.

Identifiable fluorescent markers were developed as tracers to tail suspects using phenanthrene, anthracene, fluoranthene, pyrene, perylene, and coronene in vaseline. Vaseline was used as a carrier of the marker. Of the six compounds in the vaseline, perylene and fluoranthene were readily observed under ultraviolet (UV) light at a wavelength of 365 nm. All six compounds were identified selectively and sensitively without interference of vaseline using a high performance liquid chromatograph (HPLC) with a fluorescence detector. The detection limit was much less than 1 ng, corresponding to that of the observation behavior under UV light. The results showed that each component with vaseline was more effective than the individual component for the delay in degradation. The case examples of the fluorescent markers are shown.

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