高效液相色谱-串联质谱法测定化妆品中3种甲基咪唑类化合物OA北大核心CSTPCDMEDLINE

Methylimidazole compounds are byproducts formed during the caramel-coloring process and are used in various cosmetics.In addition metronidazole is an antibacterial and anti-inflammatory drug commonly used in modem medicine and is used in cosmetics to treat acne in the short-term.The illegal addition of metronidazole during cosmetics production can result in residual 2-methylimidazole(2-MEI),which,along with 4-methylimidazole(4-MEI),is a class 2B carcinogen.Therefore,establishing efficient,accurate,and sensitive analytical techniques for analyzing methylimidazole compounds in cosmetics is an urgent objective.In this study,a high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method for simultaneously determining 1-methylimidazole(1-MEI),2-MEI,and 4-MEI in cosmetics was developed.Cosmetics samples were extracted via ultrasonication in acetonitrile and purified using a mixed cation-exchange(MCX)solid-phase extraction(SPE)column,with subsequent drying under a stream of nitrogen and redissolution in acetonitrile.The resulting so-lution was then filtered through a 0.22 μam organic filter membrane for further testing.The ana-lytes were separated using an XBridge® shield RP18 chromatographic column(150 mm×4.6 mm,3.5 μm)and isocratically eluted with 20 mmol/L ammonium formate solution(containing 0.1％formic acid)-acetonitrile(98∶2,v/v).The target compounds were ionized by electros-pray ionization(ESI)source,analyzed in multi-reaction monitoring(MRM)mode,and quanti-fied using the external standard method,with the peak area of the quantitative ion and the mass concentration of the compound taken as the longitudinal and transverse coordinates,respec-tively.Matrix-matching working curves were also constructed.1-MEI exhibited good linear rela-tionships in the range of 5-200 μg/L,with correlation coefficients(r2)≥0.999 4,while 2-MEI and 4-MEI showed good linearities in the range of 2-100 µg/L with r2 ≥ 0.998 4.The three methylimidazole compounds exhibited limits of detection(LODs)and quantification(LOQs)of 10-30 μg/kg and 25-100 µg/kg,respectively.Under three spiked levels(LOQ,2LOQ,10LOQ),the recoveries of three methylimidazole compounds were 80.9％-107.9％,with rela-tive standard deviations(RSDs,n=6)of 1.2％-12.8％.The practicability of the method was examined using 48 cosmetic samples;4-MEI was detected in nine samples at contents of 26-1 000 µg/kg,while two samples contained 240 and 267 μg/kg of 2-MEI,respectively.1-MEI was not detected in any of the 48 samples tested.The developed method is simple,fast,and highly sensitive,and provides methodological support for assessing risks and monitoring the three methylimidazole compounds in cosmetics through screening.