Halobenzoquinones (HBQs), which are emerging chlorinated disinfection byproducts (DBPs), have attracted increasing attention because they are frequently detected in treated tap water, entrainment water, etc. These compounds are mainly generated during the water treatment process using chlorine, chloramine, and chlorine dioxide as disinfectants, and display more toxic effects than regulated DBPs, such as trihalomethane and haloacetic acid. HBQs have been recognized as potential bladder carcinogens and are harmful to the nervous system. Additionally, they can exert genotoxic effects and cause oxidative damage to DNA and proteins. The risk of HBQs in aquatic products is expected to rise because the disinfection of public facilities has significantly increased in recent years. Therefore, developing a sensitive and accurate analytical method to detect HBQs in aquatic products is of great importance. Several analytical methods, including gas chromatography, gas chromatography-mass spectrometry, electrochemical methods, liquid chromatography, and liquid chromatography-tandem mass spectrometry, can be used to identify and quantify HBQs in water. However, to the best of our knowledge, no reports on the determination of HBQ levels in aquatic products are yet available. Further, pretreatment is essential for HBQ determination because of the complex matrix effects of aquatic products. Herein, a sensitive and accurate method based on the QuEChERS technique coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of five HBQs in aquatic products. For the QuEChERS procedure, the pretreatment conditions, such as the extraction solvent and adsorbent species, were systematically optimized. The sample was extracted with 10 mL of 10% methanol acetonitrile solution (containing 0.1% formic acid), dehydrated, and centrifuged with sodium chloride and anhydrous magnesium sulfate. The supernatant was purified using a QuEChERS packing material consisting of 50 mg N-propylethylenediamine (PSA), 30 mg of graphitized carbon black (GCB), and 30 mg of neutral alumina (Al2O3), dried with nitrogen, and concentrated. The five HBQs were separated on a Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) using 0.25% acetonitrile formate solution and 0.25% formic acid aqueous solution as the mobile phase under a gradient elution program and then detected using UPLC-MS/MS with negative electrospray ionization (ESI-) under multiple reaction monitoring (MRM) mode. Quantitative analysis was performed using a matrix-matched external standard method. The five HBQs achieved rapid separation within 6 min, indicating that the proposed method has a much shorter separation time compared with previous studies. The matrix effect was evaluated by establishing a matrix-matched calibration curve. The results showed that 2,5-dichloro-1,4-benzoquinone (2,5-DCBQ) presented a matrix-enhancing effect, whereas the other HBQs displayed matrix-inhibiting effects. In particular, tetrachlorobenzoquinone (TCBQ) exhibited strong inhibitory effects. Under the optimized experimental conditions, the five HBQs demonstrated good linear relationships in the range of 1.0-50.0 μg/L, with correlation coefficients (r)≥0.9992. The detection limits of the method were 0.15-0.8 μg/kg, and the recoveries of the target compounds were 85.9%-116.5%. The relative standard deviations were 1.4%-8.2%, which indicates good reproducibility. The proposed method was successfully applied to actual sample detection, and 2,6-dichloro-3-methyl-1,4-benzoquinone (2,6-DCMBQ) was detected in grass carp. The proposed method is convenient, sensitive, accurate, and suitable for the simultaneous determination of five HBQs in aquatic products. Moreover, the developed method provides a reliable reference for the routine monitoring of trace HBQs in food samples.
随着消毒剂在环境中的广泛使用,水体中卤代苯醌(HBQs)存在的风险逐渐升高,建立水产品中HBQs的检测方法具有重要的现实意义。本研究建立了基于QuEChERS-超高效液相色谱-串联质谱(UPLC-MS/MS)快速测定水产品中5种HBQs含量的方法。选择10%甲醇乙腈溶液(含0.1%甲酸)为提取溶剂,加入氯化钠和无水硫酸镁脱水离心,采用50 mg N-丙基乙二胺(PSA)、30 mg石墨化炭黑(GCB)和30 mg中性氧化铝(Al2O3)组合吸附剂对上清液进行吸附净化,净化液经氮气吹至近干,乙腈复溶后上机测定。待测物以0.25%甲酸乙腈溶液和0.25%甲酸水溶液为流动相,通过Waters ACQUITY UPLC BEH C18色谱柱(100 mm×2.1 mm, 1.7 μm)分离,在电喷雾负离子(ESI-)、多反应监测(MRM)模式下进行测定,采用基质匹配标准曲线定量。5种HBQs在6 min内可达到较好的色谱分离,同时通过空白基质加标工作曲线评价基质效应,其中2,5-二氯-1,4-苯醌(2,5-DCBQ)存在基质增强效应,其余HBQs为基质抑制效应,特别是四氯苯醌(TCBQ)呈现强基质抑制效应。在优化的条件下,5种HBQs在1.0~50.0 μg/L范围内具有良好的线性关系,相关系数(r)≥0.9992,方法检出限为0.15~0.8 μg/kg;在低、中、高3个加标水平下,5种HBQs的加标回收率为85.9%~116.5%,相对标准偏差(RSD)为1.4%~8.2%。该方法可实现HBQs在水产品中的快速富集与净化,具有灵敏度低、操作简便、重复性好等优势,可为水产品中痕量HBQs的大规模监测用提供技术支持。
Keywords: QuEChERS; aquatic products; halobenzoquinones (HBQs); ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).