Application of New Mass Spectrometric Techniques to Legal Medicine

In the fields of legal medicine and forensic toxicology, numerous drugs and poisons obtained from diverse biological specimens such as whole blood, urine, and hair need to be identified and quantified. Therefore, it is necessary to develop new methods for analysis of drugs, especially mass spectrometric methods. In this paper, we introduce three methods—surface ionization organic mass spectrometry, a combination of mass spectrometry and cryogenic oven trapping (COT), and laser spray ionization (LSI)—and their application to legal medicine. Gas chromatography/surface ionization organic mass spectrometry is very sensitive in detecting drugs containing tertiary amine residues; for Phencyclidine (PCP), its sensitivity is 20 to 1,000 times higher than that of the conventional electron ionization method. Surface ionization organic mass spectrometry is suitable for compounds containing cyclic tertiary amino side chains. COT in combination with gas chromatography has enabled detection of many volatile organic compounds (VOCs) with high sensitivity. We have succeeded in quantifying several VOCs, such as chloroform, cyanide, thinner components, ethanol, and general anesthetics in whole blood by COT; COT affords a sensitivity that is 10 to 50 times higher than that of the conventional headspace gas chromatography method. Recently, we succeeded in identifying and quantifying 15 VOCs in human whole blood with the combination of COT and mass spectrometry. LSI is a new ionization method for liquid chromatography/mass spectrometry. We have succeeded in detecting aconitine alkaloids and psychopharmaceuticals using LSI. In the infusion mode, aconitine and haloperidol were ionized with higher efficiency compared to that in the conventional electrospray mode. However, since the signals in the LSI mode are not stable, it is necessary to improve the stability of signals in the LSI mode for applying LSI to forensic toxicology.