Analytical method of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in human hair by column-switching liquid chromatography–mass spectrometry

A column-switching liquid chromatography–mass spectrometry was developed for quantification of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in human hair. Hair sample was digested in 1N NaOH at 100 °C, and PhIP was extracted using a Blue-Chitin column. The recovery rate was 73%, the limit of quantification was 50 pg/g hair, and intra-day and inter-day variations were 6.3 and 11.7%, respectively. PhIP was found in 42 of the 46 hair samples from 23 healthy volunteers: 110–3878 pg/g hair. The intrapersonal correlation between the first and second analyses was r=0.85 (95% confidence interval, 0.65–0.94). A positive correlation was observed between PhIP levels and melanin content in hair. This study indicates the ability of this method to detect levels of PhIP in hair.