title: An improved and validated sample cleanup method for analysis of ethyl carbamate in Chinese liquor.
abstract: Ethyl carbamate (EC) is a potential human carcinogen widely existing in fermented foods and alcoholic beverages. The solid-phase extraction (SPE) coupled to gas chromatography mass spectrometry is a widely-used method to determine EC levels, but the accuracy varies with sample matrix and the effects of operation parameters are rarely examined. In this study, the influence factors involved in EC determination were investigated using Chinese liquor as sample matrix, and the improved method was further applied. Three types of SPE columns, including diatomite, Florisil, and primary-secondary amine, were compared in extraction efficiency, and the diatomite column exhibited the highest extraction efficiency. The optimal volumes of elution solvents with diatomite column were 15 mL for 3-mL samples solution loaded. In addition, the alcoholic strength for EC determination should be diluted below 20% (v/v) to avoid the enhancement of matrix-induced chromatographic response. Moreover, the pH neutralization could help improve EC recovery and peak resolution, reducing interfering effects. Based on these results, the improved method showed that the limit of detection, the limit of quantification, and average recoveries were 1.10 μg/L, 3.65 μg/L, and 93.06%, respectively. To further elucidate the underlying factors related to EC accumulation, partial least square regression analysis was conducted, and the results suggested that EC levels had the closest relationship with alcoholic strength among the remaining precursors.
authors.affiliation: College of Light Industry, Textile & Food Engineering, Sichuan Univ, Chengdu 610065, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xia
authors.forename: Huawei
authors.initials: H
authors.lastname: Yuan
authors.forename: Chongde
authors.initials: C
authors.lastname: Wu
authors.forename: Jia
authors.initials: J
authors.lastname: Zheng
authors.forename: Suyi
authors.initials: S
authors.lastname: Zhang
authors.forename: Caihong
authors.initials: C
authors.lastname: Shen
authors.forename: Bin
authors.initials: B
authors.lastname: Yi
authors.forename: Rongqing
authors.initials: R
authors.lastname: Zhou
mesh_terms: D000434:Alcoholic Beverages / Q000032:analysis; D002273:Carcinogens / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000592:standards; D006863:Hydrogen-Ion Concentration; D012015:Reference Standards; D052616:Solid Phase Extraction / Q000592:standards; D014520:Urethane / Q000032:analysis*
chemical_list: D002273:Carcinogens; D014520:Urethane
keywords: GC-MS; cleanup; ethyl carbamate; partial least square regression; solid-phase extraction