食品中有机磷酸酯阻燃剂检测技术的研究进展

有机磷酸酯(OPEs)是阻燃剂和塑化剂的主要原料,通常以添加形式存在于各种材料中,在生产和使用过程中伴随磨损和挥发易释放到环境中,现已成为新兴污染物。因为该类化合物的神经毒性、致癌性、破坏内分泌系统以及生殖系统等毒性,食品样品中OPEs的检测成为近年来关注的热点。该文重点围绕食品基质中OPEs检测存在的含量低、本底干扰严重、缺乏灵敏可靠分析方法等问题,对OPEs类化合物的性质、样品前处理、检测技术、质量控制等进行了全面评述。首先总结了30余种常见OPEs类化合物的类型、官能团、极性、沸点等理化性质,对可能的前处理和检测技术进行了理论分析;其次梳理了加速溶剂萃取(ASE)、基质固相分散萃取(MSPD)、微波辅助萃取(MAE)、超声辅助萃取(UAE)、QuEChERS、固相萃取(SPE)、凝胶渗透色谱(GPC)、分散固相萃取(d-SPE)等前处理方法在食品中OPEs化合物分析中的特点,其中UAE和QuEChERS结合多步净化能够有效降低高脂类食品的基质效应,具有良好应用前景;此外比较了气相色谱和液相色谱在分离和检测方面的优缺点,比较已有文献的检出限、回收率等数据;概括了标准品和内标物来源、过程污染与基质效应的产生原因和预防措施;最后对高分辨质谱筛查和鉴别OPEs未知代谢物,以及相关分析方法趋势进行了展望。

Advances in the development of detection techniques for organophosphate ester flame retardants in food

Organophosphate ester (OPE)-based flame retardants and plasticizers are widely utilized in various industrial products, and are being increasingly used as substitutes for gradually phased brominated flame retardants (BFRs). According to the different types of substituents used, OPEs are mainly divided into alkyls, halogenated compounds, and aromatics, which have widely varying physicochemical properties. OPEs can induce neurotoxicity, carcinogenicity, and damage in endocrine and reproductive systems in humans. Examples of halogenated OPE are tris(2-chloroisopropyl) phosphate (TCIPP) and tris(1,3-dichloropropyl) phosphate (TDCIPP), which are suspected to be carcinogenic. OPEs have emerged as pollutants in environmental and food matrices as a result of volatilization and abrasion processes. Due to its low content in the food matrix and serious background interference, there is a lack of reliable and sensitive analytical methods. Recently, there has been a focus on the detection of OPE flame retardants in food. In this paper, we have reviewed the current status and development trends of OPE detection methods in various foodstuffs. First, the physicochemical properties of more than 30 common OPEs were summarized. Even when using the same extraction solvent, there are obvious differences in extraction efficiency according to different compound properties. To simultaneously analyze multi-component OPE flame retardants in food, it is very important to choose the appropriate extraction solvent to meet the required extraction efficiency of compounds with a wide range of polarities. In addition, although OPE flame retardants are not easily hydrolyzed under neutral conditions, they will degrade to a certain extent under strong acidic and alkaline conditions. It is worth mentioning that avoiding the removal of lipids and other interferences in food matrices under strong acidic and alkaline conditions. Different pretreatment methods, such as accelerated solvent extraction, matrix solid-phase dispersion extraction, microwave-assisted extraction, ultrasonic-assisted extraction, QuEChERS, solid-phase extraction, gel permeation chromatography, and dispersive solid-phase extraction are also compared. Combining the advantages of ultrasonic assisted extraction (UAE) and QuEChERS pretreatment technology can reduce the waste of extraction solvent and internal standard solution. For lipid-rich matrices like biological samples, it is necessary to remove lipid interference by SPE columns or GPC purification. Furthermore, the characteristics of separation and detection techniques, such as GC, GC-MS/MS, and LC-MS/MS, are discussed. Comparing detection limits and recovery data with those reported in the literature, GC-MS/MS can provide improved selectivity, precision, and limits of detection in complex food matrices, but LC-MS often suffers from ion suppression, matrix interferences, and incomplete separation of some OPEs. Since electron impact (EI) has higher ionization efficiency, it produces many fragment ions, thus creating a more complete spectral library, which is conducive to structural identification. When using GC-MS/MS to determine OPE flame retardants, the EI mode was usually used. However, positive chemical ionization (PCI) and electron capture negative ionization (ECNI) modes were also used sometimes. In the section on quality control, the main sources of standards and internal standards, possible sources of blank contamination, and the research status of measures to reduce matrix effects have been reviewed. To avoid blank contamination, all the laboratory equipment should be carefully cleaned, heated at high temperatures, and rinsed with polar or non-polar organic solvents in order to remove all interfering organic residues. Isotopically labeled internal standard and isotopic dilution mass spectrum quantification methods are used to reduce matrix effects. Owing to the limited availability of commercial standards and the relatively high cost, alternative approaches, such as matrix-matched calibration or standard addition methods, are required. The screening and identification of unknown metabolites of OPEs and related analytical methods based on high resolution mass spectrometry could also be studied for precursor OPEs in foodstuffs in the future.