The detection and characterization of analgesics and anti-inflammatory drugs on high performance thin-layer chromatography plates using tandem mass spectrometry: application to drugs and metabolites in urine.

The application of tandem mass spectrometry to the analysis and identification of analgesics and non-steroidal anti-inflammatory drugs such as paracetamol, ibuprofen and indomethacin following thin-layer chromatography (TLC) is described. TLC was combined successfully with mass spectrometry and with tandem mass spectrometry using silica gel and diol-bonded silica gel high performance TLC plates. The diol-bonded phase was found to be superior for use with biological samples and enabled the identification of paracetamol, ibuprofen and salicylhippuric acid (the major metabolite of acetylsalicylic acid) in human urine extracts following normal therapeutic doses.