Liu Ying, Chan Michael, Blake Ebersole, Sy Hong, Brown Paula N
British Columbia Institute of Technology, Centre for Applied Research and Innovation, 4355 Mathissi Pl, Burnaby, BC V5G 4S8, Canada.
NaturPro Scientific LLC, 10541 Brookview Dr, Carmel, IN 46032.
J AOAC Int. 2019 May 1;102(3):878-882. doi: 10.5740/jaoacint.18-0190. Epub 2018 Sep 18.
Kombucha is a nonalcoholic, fermented tea beverage that has recently received negative attention because of documented concentrations of ethanol in excess of allowable limits of ≥0.5% alcohol by volume (ABV). Our previously reported headspace GC with flame-ionization detection (GC-FID) method was adopted by the AOAC Expert Review Panel as First Action 2016.12 in September 2016 based on published single-laboratory validation study results. This paper describes the corresponding multilaboratory study using this method to further validate its performance parameters. Four laboratories participated in the study and received practice samples, test samples, reference standards, and detailed protocols. Eight kombucha samples sent out to laboratories were randomly assigned sample numbers and were blinded in terms of content and identity. Each laboratory analyzed all samples using the GC-FID method and reported their results. Cochran's C-test and single and double Grubbs' tests were used to identify and remove outliers. Horwitz ratio values for all samples were between 0.5 and 1.7. As per the (SMPRs), all samples within the analytical range of 0.1-2.0 ABV% had RSD values <6%. The results from this study demonstrate the evaluated GC-FID method meets the SMPR requirements and is fit for purpose for detecting ethanol in kombucha products. Kombucha, a nonalcoholic, fermented beverage, has been found to contain ≥0.5% ABV. First Action 2016.12, a headspace GC-FID method for determining ethanol in kombucha, is supported by a multilaboratory study.
康普茶是一种不含酒精的发酵茶饮料，最近因其乙醇含量超过允许限度（体积分数≥0.5%酒精，即ABV）而受到负面关注。基于已发表的单实验室验证研究结果，美国官方分析化学师协会（AOAC）专家评审小组于2016年9月采用了我们先前报道的顶空气相色谱-火焰离子化检测（GC-FID）方法作为2016.12版首次行动方法。本文描述了使用该方法进行的相应多实验室研究，以进一步验证其性能参数。四个实验室参与了该研究，接收了练习样品、测试样品、参考标准品和详细方案。发送给各实验室的八个康普茶样品被随机分配样品编号，且在成分和身份方面均进行了盲编。每个实验室使用GC-FID方法分析所有样品并报告结果。使用 Cochr an's C检验以及单格拉布斯检验和双格拉布斯检验来识别和去除异常值。所有样品的霍维茨比值在0.5至1.7之间。根据标准方法性能要求（SMPRs），在0.1-2.0 ABV%分析范围内的所有样品的相对标准偏差（RSD）值均<6%。本研究结果表明，所评估的GC-FID方法符合SMPR要求，适用于检测康普茶产品中的乙醇。康普茶这种不含酒精的发酵饮料被发现含有≥0.5% ABV。2016.12版首次行动方法——一种用于测定康普茶中乙醇的顶空GC-FID方法，得到了多实验室研究的支持。
