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Caron P, Turcotte V, Lévesque E, Guillemette C. An LC-MS/MS method for quantification of abiraterone, its active metabolites D(4)-abiraterone (D4A) and 5α-abiraterone, and their inactive glucuronide derivatives. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1104:249-255. [DOI: 10.1016/j.jchromb.2018.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/15/2018] [Accepted: 12/03/2018] [Indexed: 11/29/2022]
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Pietsch C, Noser J, Wettstein FE, Burkhardt-Holm P. Unraveling the mechanisms involved in zearalenone-mediated toxicity in permanent fish cell cultures. Toxicon 2014; 88:44-61. [PMID: 24950048 DOI: 10.1016/j.toxicon.2014.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 05/30/2014] [Accepted: 06/10/2014] [Indexed: 11/29/2022]
Abstract
The world-wide occurrence of zearalenone (ZEN) as a contaminant in feed for farm animals and fish requires the evaluation of toxicity mechanisms of action of ZEN. The present study investigates possible metabolization of ZEN in fish cell lines suggesting that mainly glucuronidation takes place. It demonstrates that concentrations up to 20,000 ng ml(-1) ZEN are capable of influencing cell viability in permanent fish cell cultures in a dose-response manner with different response patterns between the five tested cell lines, whereby lysosomes appeared to be the main target of ZEN. ZEN toxicity is often discussed in the context of oxidative stress. Our study shows a biphasic response of the cell lines when reactive oxygen species (ROS) production is monitored. Damage in cells was observed by measuring lipid peroxidation, DNA strand breaks, and alterations of intracellular glutathione levels. Metabolization of ZEN, especially at concentrations above 7500 ng ml(-1) ZEN, does not prevent cytotoxicity. ZEN as an estrogenic compound may involve processes mediated by binding to estrogen receptors (ER). Since one cell line showed no detectable expression of ER, an ER-mediated pathway seems to be unlikely in these cells. This confirms a lysosomal pathway as a main target of ZEN in fish cells.
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Affiliation(s)
- Constanze Pietsch
- Zurich University of Applied Sciences (ZHAW), Institute of Natural Resource Sciences (IUNR), Gruental, P.O. Box, CH-8820 Waedenswil, Switzerland; Programm Man - Society - Environment, Department of Environmental Sciences, University of Basel, Vesalgasse 1, CH-4051 Basel, Switzerland.
| | - Jürg Noser
- Kantonales Laboratorium Basel, Gräubernstrasse 12, CH-4410 Liestal, Switzerland
| | - Felix E Wettstein
- Agroscope Reckenholz-Tänikon (ART), Research Station ART, Reckenholzstrasse 191, CH-8046 Zürich, Switzerland
| | - Patricia Burkhardt-Holm
- Programm Man - Society - Environment, Department of Environmental Sciences, University of Basel, Vesalgasse 1, CH-4051 Basel, Switzerland; Department of Biological Sciences, University of Alberta, CW 405 Biological Sciences Building, T6G 2E9, Edmonton, AB, Canada
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Busquets R, Frandsen H, Jönsson JÅ, Puignou L, Galceran MT, Skog K. 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. Chem Res Toxicol 2013; 26:233-40. [DOI: 10.1021/tx3003966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Rosa Busquets
- Nanoscience & Nanotechnology Group, Faculty of Science and Engineering, University of Brighton, BN2 4GJ, Brighton, United Kingdom
- Department of Analytical Chemistry, University of Barcelona, E-08028, Barcelona, Spain
| | - Henrik Frandsen
- National Food Institute, Technical University of Denmark, DK-2860, Søborg,
Denmark
| | | | - Lluís Puignou
- Department of Analytical Chemistry, University of Barcelona, E-08028, Barcelona, Spain
| | - Maria Teresa Galceran
- Department of Analytical Chemistry, University of Barcelona, E-08028, Barcelona, Spain
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Turesky RJ, Le Marchand L. Metabolism and biomarkers of heterocyclic aromatic amines in molecular epidemiology studies: lessons learned from aromatic amines. Chem Res Toxicol 2011; 24:1169-214. [PMID: 21688801 PMCID: PMC3156293 DOI: 10.1021/tx200135s] [Citation(s) in RCA: 217] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Aromatic amines and heterocyclic aromatic amines (HAAs) are structurally related classes of carcinogens that are formed during the combustion of tobacco or during the high-temperature cooking of meats. Both classes of procarcinogens undergo metabolic activation by N-hydroxylation of the exocyclic amine group to produce a common proposed intermediate, the arylnitrenium ion, which is the critical metabolite implicated in toxicity and DNA damage. However, the biochemistry and chemical properties of these compounds are distinct, and different biomarkers of aromatic amines and HAAs have been developed for human biomonitoring studies. Hemoglobin adducts have been extensively used as biomarkers to monitor occupational and environmental exposures to a number of aromatic amines; however, HAAs do not form hemoglobin adducts at appreciable levels, and other biomarkers have been sought. A number of epidemiologic studies that have investigated dietary consumption of well-done meat in relation to various tumor sites reported a positive association between cancer risk and well-done meat consumption, although some studies have shown no associations between well-done meat and cancer risk. A major limiting factor in most epidemiological studies is the uncertainty in quantitative estimates of chronic exposure to HAAs, and thus, the association of HAAs formed in cooked meat and cancer risk has been difficult to establish. There is a critical need to establish long-term biomarkers of HAAs that can be implemented in molecular epidemioIogy studies. In this review, we highlight and contrast the biochemistry of several prototypical carcinogenic aromatic amines and HAAs to which humans are chronically exposed. The biochemical properties and the impact of polymorphisms of the major xenobiotic-metabolizing enzymes on the biological effects of these chemicals are examined. Lastly, the analytical approaches that have been successfully employed to biomonitor aromatic amines and HAAs, and emerging biomarkers of HAAs that may be implemented in molecular epidemiology studies are discussed.
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Affiliation(s)
- Robert J Turesky
- Division of Environmental Health Sciences, Wadsworth Center , Albany, New York 12201, United States.
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Teunissen SF, Rosing H, Brunsveld L, de Greef TFA, Durmus S, Schellens JHM, Schinkel AH, Beijnen JH. Analysis of 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and Its Phase I and Phase II Metabolites in Mouse Urine Using LC–UV–MS–MS. Chromatographia 2011. [DOI: 10.1007/s10337-011-2068-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Gu D, Raymundo MM, Kadlubar FF, Turesky RJ. Ultraperformance liquid chromatography-tandem mass spectrometry method for biomonitoring cooked meat carcinogens and their metabolites in human urine. Anal Chem 2010; 83:1093-101. [PMID: 21194225 DOI: 10.1021/ac102918b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cooked meat carcinogens 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and their principal metabolites produced by cytochrome P450 and/or uridine diphosphate glucuronosyl transferases were simultaneously measured at the parts per trillion level in urine of omnivores, by ultraperformance liquid chromatography (UPLC) with a Michrom Advance CaptiveSpray source and a triple stage quadrupole mass spectrometer. Quantitation was performed in the selected reaction monitoring mode. The UPLC method is much more rapid and sensitive than our earlier capillary HPLC method: the duty cycle of the UPLC method is 19 min compared to 57 min for capillary HPLC. The performance of the UPLC assay was evaluated with urine samples from three subjects over 4 different days. The intraday and interday precisions of the estimates of PhIP, MeIQx, and their metabolites, reported as the coefficients of variation, were ≤10%. The limit of quantification (LOQ) values for PhIP and MeIQx were about 5 pg/mL, whereas the LOQ values of their metabolites ranged from 10 to 40 pg/mL. Furthermore, the identities of the analytes were corroborated by acquisition of full scan product ion spectra, employing between 0.5 and 5 pg of analyte for assay.
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Affiliation(s)
- Dan Gu
- Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, New York 12201, USA
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7
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Teunissen S, Vlaming M, Rosing H, Schellens J, Schinkel A, Beijnen J. Development and validation of a liquid chromatography–tandem mass spectrometry assay for the analysis of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and its metabolite 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP) in plasma, urine, bile, intestinal contents, faeces and eight selected tissues from mice. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:2353-62. [DOI: 10.1016/j.jchromb.2010.07.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 07/05/2010] [Accepted: 07/20/2010] [Indexed: 12/29/2022]
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Vaz ADN, Wang WW, Bessire AJ, Sharma R, Hagen AE. A rapid and specific derivatization procedure to identify acyl-glucuronides by mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:2109-2121. [PMID: 20552710 DOI: 10.1002/rcm.4621] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A simple procedure is described to identify acyl-glucuronides by coupled liquid chromatography/mass spectrometry after derivatization to a hydroxamic acid with hydroxylamine. The reaction specificity obviates the need for isolation of the acyl-glucuronide from an extract. Glucuronides derived from carbamic acids, and alkyl- and aromatic amines, are inert to the derivatization reaction conditions, making the hydroxamic acid derivative a fingerprint for acyl-glucuronides.
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Affiliation(s)
- Alfin D N Vaz
- Department of Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, Groton, CT 06340, USA.
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Gu D, McNaughton L, Lemaster D, Lake BG, Gooderham NJ, Kadlubar FF, Turesky RJ. A comprehensive approach to the profiling of the cooked meat carcinogens 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, and their metabolites in human urine. Chem Res Toxicol 2010; 23:788-801. [PMID: 20192249 DOI: 10.1021/tx900436m] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A targeted liquid chromatography/tandem mass spectrometry-based metabolomics type approach, employing a triple stage quadrupole mass spectrometer in the product ion scan and selected reaction monitoring modes, was established to profile 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and their principal metabolites in the urine of omnivores. A mixed-mode reverse phase cation exchange resin enrichment procedure was employed to isolate MeIQx and its oxidized metabolites, 2-amino-8-(hydroxymethyl)-3-methylimidazo[4,5-f]quinoxaline (8-CH(2)OH-IQx) and 2-amino-3-methylimidazo[4,5-f]quinoxaline-8-carboxylic acid (IQx-8-COOH), which are produced by cytochrome P450 1A2 (P450 1A2). The phase II conjugates N(2)-(beta-1-glucosiduronyl)-2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and N(2)-(3,8-dimethylimidazo[4,5-f]quinoxalin-2-yl)-sulfamic acid were measured indirectly, following acid hydrolysis to form MeIQx. The enrichment procedure permitted the simultaneous analysis of PhIP, N(2)-(beta-1-glucosidurony1)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, N3-(beta-1-glucosidurony1)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1-methyl-6-(4'-hydroxy)-phenylimidazo[4,5-b]pyridine (4'-HO-PhIP), and the isomeric N(2)- and N3-glucuronide conjugates of the carcinogenic metabolite, 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (HONH-PhIP), which is formed by P450 1A2. The limit of quantification (LOQ) for MeIQx, PhIP, and 4'-HO-PhIP was approximately 5 pg/mL; the LOQ values for 8-CH(2)OH-IQx and IQx-8-COOH were, respectively, <15 and <25 pg/mL, and the LOQ values for the glucuronide conjugates of PhIP and HONH-PhIP were 50 pg/mL. The metabolism was extensive; less than 9% of the dose was eliminated in urine as unaltered MeIQx, and <1% was eliminated as unaltered PhIP. Phase II conjugates of the parent amines accounted for up to 12% of the dose of MeIQx and up to 2% of the dose of PhIP. 8-CH(2)OH-IQx and IQx-8-COOH accounted for up to 76% of the dose of MeIQx, and the isomeric glucuronide conjugates of HONH-PhIP accounted for up to 33% of the dose of PhIP that were eliminated in urine within 10 h of meat consumption. P450 1A2 significantly contributes to the metabolism of both HAAs but with marked differences in substrate specificity. P450 1A2 primarily catalyzes the detoxification of MeIQx by oxidation of the 8-methyl group, whereas it catalyzes the bioactivation of PhIP by oxidation of the exocyclic amine group.
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Affiliation(s)
- Dan Gu
- Division of Environmental Health Sciences, New York State Department of Health, Albany, New York 12201, USA
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Busquets R, Jönsson JÅ, Frandsen H, Puignou L, Galceran MT, Skog K. Hollow fibre-supported liquid membrane extraction and LC-MS/MS detection for the analysis of heterocyclic amines in urine samples. Mol Nutr Food Res 2009; 53:1496-504. [DOI: 10.1002/mnfr.200800577] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Determination of Heterocyclic Amines in Atmospheric Particles by Reversed Phase High Performance Liquid Chromatography. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2009. [DOI: 10.1016/s1872-2040(08)60134-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Fede JM, Thakur AP, Gooderham NJ, Turesky RJ. Biomonitoring of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and its carcinogenic metabolites in urine. Chem Res Toxicol 2009; 22:1096-105. [PMID: 19441775 DOI: 10.1021/tx900052c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a carcinogenic heterocyclic aromatic amine that is produced in cooked meats. The simultaneous analysis of PhIP and its metabolites in human urine is a challenge, because these biomarkers only occur in urine at parts per billion or lower concentrations and must be selectively purifed from thousands of other urinary constituents. We have developed a facile solid-phase extraction method, employing a mixed-mode reverse-phase cation exchange resin, to simultaneously isolate PhIP, its glucuronide conjugates, and the glucuronide conjugates of the genotoxic metabolite 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine from the urine of meat eaters. PhIP and its metabolites were quantified by liquid chromatography-electrospray ionization/tandem mass spectrometry (LC-ESI/MS/MS), using a triple stage quadrupole mass spectrometer in the selected reaction monitoring scan mode. The lower limit of quantification (LOQ) of PhIP is 5 parts per trillion (ppt), and the LOQ values for the glucuronide conjugates are 50 ppt, when 25 microL of urine is employed for assay. The extraction scheme is versatile and has been employed to isolate other ring-hydroxylated and glucuronidated metabolites of PhIP, for characterization by LC-ESI/MS/MS.
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Affiliation(s)
- Jean-Marie Fede
- Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, New York 12201, USA
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Busquets R, Mitjans D, Puignou L, Galceran MT. Quantification of heterocyclic amines from thermally processed meats selected from a small-scale population-based study. Mol Nutr Food Res 2008; 52:1408-20. [DOI: 10.1002/mnfr.200800048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Frandsen H. Biomonitoring of urinary metabolites of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) following human consumption of cooked chicken. Food Chem Toxicol 2008; 46:3200-5. [PMID: 18692111 DOI: 10.1016/j.fct.2008.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 05/27/2008] [Accepted: 07/14/2008] [Indexed: 12/16/2022]
Abstract
Human risk assessment of exposure to 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) through the diet may be improved by conducting biomonitoring studies comparing metabolism in humans and rodents. Eleven volunteers ingested a meal of cooked chicken containing 4 -OH-PhIP and PhIP in amounts of 0.6 and 0.8microg/kg, respectively and urine was collected for the next 16h. The large number of PhIP metabolites was by treatment of the urine samples with hydrazine hydrate and hydrolytic enzymes reduced to three substances, 4'-OH-PhIP, PhIP and 5-OH-PhIP of which the first is a biomarker for detoxification and the last a biomarker for activation. The eleven volunteers eliminated large amounts of 4'-OH-PhIP in the urine. The majority of which could be accounted for by the presence of 4'-OH-PhIP in the fried chicken, showing that PhIP only to a small extent (11%) was metabolised to 4'-OH-PhIP. A larger fraction of the PhIP exposure, 38%, was recovered as PhIP and the largest fraction (51%) was recovered as 5-OH-PhIP suggesting that PhIP in humans to a large extent is metabolised to reactive substances. In rats, less than 1% of the dose of PhIP was eliminated as 5-OH-PhIP, suggesting that human cancer risk from exposure to PhIP is considerable higher than risk estimations based on extrapolation from rodent bioassays.
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Affiliation(s)
- H Frandsen
- National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
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Busquets R, Puignou L, Galceran MT, Wakabayashi K, Skog K. Liquid chromatography-tandem mass spectrometry analysis of 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5-b]pyridine in cooked meats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:9318-9324. [PMID: 17924706 DOI: 10.1021/jf072252q] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Several cooked meats such as beef (fried, coated-fried), pork (fried, coated-fried), and chicken (fried, griddled, coated-fried, roasted) were analyzed for the heterocyclic amine 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5- b]pyridine (4'-OH-PhIP) not commonly determined in food and 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP). The highest content of 4'-OH-PhIP was found in fried and griddled chicken breast, the concentration being 43.7 and 13.4 ng/g, respectively, whereas the corresponding PhIP concentrations were 19.2 and 5.8 ng/g. The estimated concentration of both pyridines in fried pork loin, in fried pork sausages, and in coated-fried chicken was below 2.5 ng/g. In the rest of the samples, 4'-OH-PhIP was not detected. The analyses were performed by solid-phase extraction and LC-MS/MS. The fragmentation of 4'-OH-PhIP in an ion trap mass analyzer was studied in order to provide information for the identification of 4'-OH-PhIP. Additionally, the effect of red wine marinades on the formation of 4'-OH-PhIP in fried chicken was examined, finding a notable reduction (69%) in the amine's occurrence.
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Affiliation(s)
- R Busquets
- Department of Analytical Chemistry, Chemistry Faculty, University of Barcelona, Martí i Franquès, 1-11, E-08028 Barcelona, Spain
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Murkovic M. Analysis of heterocyclic aromatic amines. Anal Bioanal Chem 2007; 389:139-46. [PMID: 17546447 DOI: 10.1007/s00216-007-1306-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2007] [Revised: 04/05/2007] [Accepted: 04/11/2007] [Indexed: 10/23/2022]
Abstract
Heterocyclic aromatic amines are formed in protein and amino acid-rich foods at temperatures above 150 degrees C. Of more than twenty heterocyclic aromatic amines identified ten have been shown to have carcinogenic potential. As nutritional hazards, their reliable determination in prepared food, their uptake and elimination in living organisms, including humans, and assessment of associated risks are important food-safety issues. The concentration in foods is normally in the low ng g(-1) range, which poses a challenge to the analytical chemist. Because of the complex nature of food matrixes, clean-up and enrichment of the extracts are also complex, usually involving both cation-exchange (propylsulfonic acid silica gel, PRS) and reversed-phase purification. The application of novel solid-phase extraction cartridges with a wettable apolar phase combined with cation-exchange characteristics simplified this process--both the polar and apolar heterocyclic aromatic amines were recovered in one fraction. Copper phthalocyanine trisulfonate bonded to cotton ("blue cotton") or rayon, and molecular imprinted polymers have also been successfully used for one-step sample clean-up. For analysis of the heterocyclic aromatic amines, liquid chromatography with base-deactivated reversed-phase columns has been used, and, recently, semi-micro and capillary columns have been introduced. The photometric, fluorimetric, or electrochemical detectors used previously have been replaced by mass spectrometers. Increased specificity and sub-ppb sensitivities have been achieved by the use of the selected-reaction-monitoring mode of detection of advanced MS instrumentation, for example the triple quadrupole and Q-TOF instrument combination. Gas chromatography, also with mass-selective detection, has been used for specific applications; the extra derivatization step needed for volatilization has been balanced by the higher chromatographic resolution.
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Affiliation(s)
- M Murkovic
- Institute for Food Chemistry and Technology, Graz University of Technology, Petersgasse 12/2, Graz, Austria.
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