On-line capillary based quantitative analysis of a heterocyclic amine in human urine

A high through-put miniaturised separation-quantification method for the heterocyclic aromatic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in urine was developed. The limit of detection was of 0.65 fmol (0.14 pg) injected or 65 pM. Heterocyclic aromatic amines are mutagenic and carcinogenic compounds formed at low levels in protein-rich food during cooking. Due to the low concentrations and the high complexity of the matrix in which they exist (food, blood, and urine), and the often small sample volumes (capillary blood; urine, blood and milk from small animals), very sensitive and selective analytical methods are required for their detection. Miniaturisation was accomplished by micro solid-phase extraction in capillaries with blue chitin as solid-phase, coupled on-line (in-capillary) to capillary electrophoresis with nanospray tandem mass spectrometric detection. This new technique provided a total analysis time of only 15 min, including extraction and separation, together with low sample and solvent consumption. Blue chitin showed high tolerance towards the urine matrix. Urine collected 12 h after consumption of fried chicken contained 1.8 nmol L−1 (0.40 pg μL−1) of PhIP.