Quantification of urinaryN-acetyl-S- (propionamide)cysteine using an on-line clean-up system coupled with liquid chromatography/tandem mass spectrometry
作者:Chien-Ming Li、Chiung-Wen Hu、Kuen-Yuh Wu
DOI:10.1002/jms.823
日期:2005.4
Acrylamide has been reported to be present in high-temperature processed foods and normal processed food intake could lead to significant acrylamide exposure. Acrylamide in vivo can be conjugated with glutathione in the presence of glutathione transferase. This conjugation product is further metabolized and excreted as N-acetyl-S-(propionamide)cysteine (NASPC) in the urine. NASPC could be considered a biomarker for acrylamide exposure. The objective of this study was to develop a highly specific, rapid and sensitive method to quantify urinary NASPC, serving as a biomarker for acrylamide exposure assessment. Isotope-labeled [13C3]NASPC was successfully synthesized and used as an internal standard. This urine mixture was directly analyzed using a newly developed liquid chromatographic/tandem mass spectrometric method coupled with an on-line clean-up system. The detection limit for this method was estimated as <5 µg l−1(0.4 pmol) on-column. The method was applied to measure the urinary level of NASPC in 70 apparently health subjects. The results showed that the NASPC urinary level was highly associated with smoking. Smokers had a significantly higher urinary NASPC level (135 ± 88 µg g−1 creatinine) than non-smokers (76 ± 30 µg g−1 creatinine). A highly sensitive and selective LC/MS/MS isotope dilution method was successfully established. With an on-line clean-up system, this system is capable of routine high-throughput analysis and accurate quantitation of NASPC in urine. This could be a useful tool for health surveillance for acrylamide exposure in a population for future study. Copyright © 2005 John Wiley & Sons, Ltd.
据报道,高温加工食品中含有丙烯酰胺,正常摄入加工食品会导致摄入大量丙烯酰胺。在体内,丙烯酰胺可在谷胱甘肽转移酶的作用下与谷胱甘肽结合。这种共轭产物会进一步代谢,并以 N-乙酰-S-(丙酰胺)半胱氨酸(NASPC)的形式随尿液排出体外。NASPC 可被视为丙烯酰胺暴露的生物标志物。这项研究的目的是开发一种高度特异、快速和灵敏的方法来量化尿液中的 NASPC,作为评估丙烯酰胺摄入量的生物标志物。成功合成了同位素标记的 [13C3]NASPC 并将其用作内标。利用新开发的液相色谱/串联质谱法和在线净化系统直接分析了这种尿液混合物。该方法的柱上检出限估计为小于 5 µg l-1(0.4 pmol)。该方法用于测定 70 名表面健康的受试者尿中 NASPC 的含量。结果表明,NASPC 尿液水平与吸烟密切相关。吸烟者尿液中的 NASPC 水平(135 ± 88 µg g-1 肌酐)明显高于非吸烟者(76 ± 30 µg g-1 肌酐)。成功建立了一种高灵敏度和高选择性的 LC/MS/MS 同位素稀释法。通过在线净化系统,该系统能够对尿液中的 NASPC 进行常规高通量分析和准确定量。这将成为监测人群丙烯酰胺摄入量的有效工具,供今后研究使用。Copyright © 2005 John Wiley & Sons, Ltd. All Rights Reserved.