School of Pharmaceutical Science, Guangxi Medical University, Nanning, Guangxi 530021, China.
Guangxi Zhuang Autonomous Region Center for Disease Prevention and Control, Nanning, Guangxi 530028, China.
Anal Methods. 2020 May 14;12(18):2308-2316. doi: 10.1039/d0ay00534g.
Aflatoxins (AFs), as the secondary metabolites of the toxigenic fungi Aspergillus flavus and Aspergillus parasiticus, are well known to be extremely harmful to humans and animals because of their high toxicity, mutagenicity, carcinogenicity, and teratogenicity. Recurring and increasing studies on AF ingestion incidents indicate that AF contamination is a serious food safety issue worldwide. Currently, immunoaffinity chromatography (IAC) has become the most conventional sample clean-up method for determining AFs in foodstuffs. However, the IAC method may be limited to some laboratories because it requires the use of expensive disposable cartridges and the IA procedure is time-consuming. Herein, to achieve the cost-effective determination of AFs in edible oils, we developed a dispersive solid-phase extraction (DSPE) clean-up method based on humic acids (HAs), which is followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. HAs could be directly used as a DSPE sorbent after simple treatment without any chemical modification. In the HA-DSPE, AFs could remain on the HA sorbent by both hydrophobic and hydrophilic interactions, whereas the oil matrix was retained on HA via only hydrophobic interactions. The oil matrix could be sufficiently washed off by n-hexane, whereas the AFs could still be retained on HA; thus, the selective extraction of AFs and clean-up of oil matrices were achieved. Under the optimal conditions of HA-DSPE, satisfactory recoveries ranging from 81.3% to 106.2% for four AFs (B1, B2, G1, and G2) were achieved in various oil matrices i.e. blended oil, mixed olive oil, tea oil, sunflower seed oil, rapeseed oil, sesame oil, soybean oil, rice oil, corn oil, and peanut oil. Minor matrix effects ranging from 89.3% to 112.9% were obtained for the four AFs, which were acceptable. Moreover, the LODs of AFs between 0.063 and 0.102 μg kg-1 completely meet the regulatory levels fixed by the Food and Drug Administration (FDA), the European Union (EU), China, or other countries. The proposed methodology was further validated using a naturally contaminated peanut oil, and the results indicated that the accuracy of the HA-DSPE could match the accuracy of the referenced IAC. In addition, HA-DSPE can be used to directly treat diluted edible oil without liquid-liquid extraction and HA is cheap and can be easily obtained from the market worldwide; these advantages make the proposed methodology simple, low-cost, and accessible for the determination of AFs in edible oils.
黄曲霉毒素(AFs)是产毒真菌黄曲霉和寄生曲霉的次级代谢产物,由于其毒性、致突变性、致癌性和致畸性极高,被公认为对人类和动物极其有害。越来越多的关于摄入黄曲霉毒素事件的研究表明,黄曲霉毒素污染是一个严重的全球食品安全问题。目前,免疫亲和色谱法(IAC)已成为测定食品中黄曲霉毒素最常用的样品净化方法。然而,由于该方法需要使用昂贵的一次性试剂盒,且免疫亲和(IA)过程耗时,因此可能仅限于某些实验室。在此,为了在经济上可行地测定食用油中的黄曲霉毒素,我们开发了一种基于腐殖酸(HA)的分散固相萃取(DSPE)净化方法,随后采用液相色谱-串联质谱(LC-MS/MS)分析。腐殖酸经过简单处理后可直接用作 DSPE 吸附剂,无需任何化学修饰。在 HA-DSPE 中,AFs 可以通过疏水相互作用和氢键与 HA 吸附剂结合,而油基质仅通过疏水相互作用保留在 HA 上。油基质可以用正己烷充分洗脱,而 AFs 仍保留在 HA 上,从而实现了 AFs 的选择性萃取和油基质的净化。在 HA-DSPE 的最佳条件下,四种黄曲霉毒素(B1、B2、G1 和 G2)在各种油基质(如混合油、混合橄榄油、茶籽油、葵花籽油、菜籽油、芝麻油、大豆油、米糠油、玉米油和花生油)中的回收率在 81.3%至 106.2%之间,结果令人满意。四种黄曲霉毒素的基质效应在 89.3%至 112.9%之间,结果可以接受。此外,黄曲霉毒素的检测限(LOD)在 0.063 至 0.102μgkg-1 之间,完全符合美国食品药品监督管理局(FDA)、欧盟(EU)、中国或其他国家规定的监管水平。该方法进一步通过天然污染的花生油进行验证,结果表明,HA-DSPE 的准确性可与参考 IAC 的准确性相匹配。此外,HA-DSPE 可直接用于处理未经液-液萃取的稀释食用油,且 HA 价格低廉,可在全球市场上轻松获得;这些优势使得该方法简单、成本低,适用于食用油中黄曲霉毒素的测定。