Analysis of (dichloromethylene) bisphosphonate in urine by capillary gas chromatography—mass spectrometry

An anion exchange extraction method of bisphosphonates from urine is described. More than 90% of the (dichloromethylene) bisphosphonate (Cl 2MBP, clodronate) was recovered from urine. The extracted bisphosphonates were trimethyl-silylated and analysed with capillary gas chromatography—mass spectrometry (GC/MS). The mass spectrometric techniques used were electron ionization (EI), ammonia chemical ionization (CI), ammonia CI tandem mass spectrometry and methane negative chemical ionization (NCI). The limit of detection of Cl 2MBP was 25 pg/injection in the NCI/selective ion recording (SIR)-mode. At 100 ng ml −1 of Cl 2MBP the precision of the whole assay method was 17.9% ( N = 6). The NCI/SIR technique offers a sensitive and highly selective method for the quantitation of Cl 2MBP in urine.