Analytical and bioanalytical chemistry
-
Review
Stability of analytes in biosamples - an important issue in clinical and forensic toxicology?
Knowledge of the stability of drugs in biological samples is important for the interpretation of toxicological findings. This paper reviews data on the stability of drugs in blood, plasma, or serum. Since such data have already been reviewed for classic drugs of abuse, the focus here is on newer drugs of abuse and on therapeutic drugs. ⋯ Instability usually only occurs for drugs carrying ester moieties, sulfur atoms, or other easily oxidized or reduced structures. Nevertheless, clinical or forensic specimens should always be stored at least in the refrigerator and preferably at -20 degrees C or lower to avoid any degradation. Finally, results obtained from biosamples that have been stored at room temperature for a longer time should be interpreted with great care and partial degradation should always be considered.
-
This paper reviews multi-analyte single-stage and tandem liquid chromatography-mass spectrometry (LC-MS) procedures using different mass analyzers (quadrupole, ion trap, time-of-flight) for screening, identification, and/or quantification of drugs, poisons, and/or their metabolites in blood, plasma, serum, or urine published after 2004. Basic information about the biosample assayed, work-up, LC column, mobile phase, ionization type, mass spectral detection mode, and validation data of each procedure is summarized in tables. ⋯ In conclusion, LC-MS will probably become a gold standard for detection of very low concentrations particularly in alternative matrices and for quantification in clinical and forensic toxicology. However, some drawbacks still need to be addressed and finally overcome.