Graphene oxide-coated stir bar sorptive extraction of trace aflatoxins from soy milk followed by high performance liquid chromatography-laser-induced fluorescence detection

Mycotoxins are potential food pollutants produced by fungi. Among them, aflatoxins (AFs) are the most toxic. Therefore, AFs were selected as models, and a sensitive, simple and green graphene oxide (GO)-based stir bar sorptive extraction (SBSE) method was developed for extraction and determination of AFs with high performance liquid chromatography-laser-induced fluorescence detector (HPLC-LIF). This method improved the sensitivity of AFs detection and solved the deposition difficulty of the direct use of GO as adsorbent. Several parameters including a spiked amount of NaCl, stirring rate, extraction time and desorption time were investigated. Under optimal conditions, the quantitative method had low limits of detection of 2.4–8.0 pg/mL, which were better than some reported AFs analytical methods. The developed method has been applied to soy milk samples with good recoveries ranging from 80.5 to 102.3%. The prepared GO-based SBSE can be used as a sensitive screening technique for detecting AFs in soy milk.

真菌毒素（Mycotoxins）是真菌产生的潜在食品污染物。其中，黄曲霉毒素（aflatoxins, AFs）的毒性最为突出。本研究选取黄曲霉毒素作为模型分析物，开发了一种灵敏、简便且绿色环保的基于氧化石墨烯（graphene oxide, GO）的搅拌棒吸附萃取（stir bar sorptive extraction, SBSE）方法，结合高效液相色谱-激光诱导荧光检测器（high performance liquid chromatography-laser-induced fluorescence detector, HPLC-LIF）用于黄曲霉毒素的萃取与定量测定。该方法提升了黄曲霉毒素检测的灵敏度，解决了直接以氧化石墨烯作为吸附剂时存在的沉积难题。研究考察了氯化钠（NaCl）添加量、搅拌速率、萃取时间及解吸时间等多项参数。在最优实验条件下，该定量方法的检出限低至2.4~8.0 pg/mL，性能优于部分已报道的黄曲霉毒素分析方法。所开发的方法已应用于豆浆样品检测，回收率区间为80.5%~102.3%，结果良好。所制备的基于氧化石墨烯的搅拌棒吸附萃取材料可作为一种灵敏的筛查技术，用于豆浆中黄曲霉毒素的检测。