title: Biomonitoring of dietary heterocyclic amines and metabolites in urine by liquid phase microextraction: 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a possible biomarker of exposure to dietary PhIP.
abstract: Heterocyclic amines (HCAs) are mutagenic/carcinogenic compounds formed at ng/g levels during frying meat or fish. The effect of the normal intake of dietary HCAs in humans and their involvement in the etiology of cancer are currently unknown. In this work, a new extraction method, liquid phase microextraction (LPME) with hollow fibers, and LC-MS/MS have been used for the first time to determine HCAs and metabolites in nonspiked human urine following a single meal of chicken cooked at 180 °C for 6 min. The total intake of HCAs was estimated to be 6 μg, of which 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) accounted for about 1 μg. The concentrations of PhIP in nonhydrolyzed urine samples ranged from 11.7 to 59.4 pg/g. The total amount of PhIP in urine ranged between 9.3 and 21.1 ng, which corresponds to 0.91-2.1% of the ingested PhIP. In addition, the urine levels of 4'-OH-PhIP (2-amino-1-methyl-6-(4'-hydroxy)phenylimidazo[4,5-b]pyridine) and 5-OH-PhIP (2-amino-1-methyl-6-(5-hydroxy)phenylimidazo[4,5-b]pyridine) also showed a narrow variation between the samples. The analysis of urine samples after acid hydrolysis did not give additional information but showed a notable increase in norharman in some cases. The obtained results suggest PhIP in urine as a possible biomarker of exposure to HCAs and the LPME and LC-MS/MS method as an appropriate strategy to biomonitor HCAs in urine.
authors.affiliation: Nanoscience & Nanotechnology Group, Faculty of Science and Engineering, University of Brighton, BN2 4GJ, Brighton, United Kingdom. rosabs5@gmail.com
authors.forename: Rosa
authors.initials: R
authors.lastname: Busquets
authors.forename: Henrik
authors.initials: H
authors.lastname: Frandsen
authors.forename: Jan Åke
authors.initials: JÅ
authors.lastname: Jönsson
authors.forename: Lluís
authors.initials: L
authors.lastname: Puignou
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Galceran
authors.forename: Kerstin
authors.initials: K
authors.lastname: Skog
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism / Q000652:urine; D002273:Carcinogens / Q000032:analysis* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003296:Cooking; D004032:Diet; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000378:metabolism* / Q000652:urine*; D059627:Liquid Phase Microextraction; D008297:Male; D008875:Middle Aged; D011725:Pyridines / Q000378:metabolism / Q000652:urine; D053719:Tandem Mass Spectrometry
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D007093:Imidazoles; D011725:Pyridines; C077584:2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo(4,5-b)pyridine; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine