Department of Analytical Chemistry, Institute of Research and Food Analysis University of Santiago de Compostela, Avda de las Ciencias s/n 15782 Santiago de Compostela, Spain.
J Chromatogr A. 2011 Sep 28;1218(39):6878-83. doi: 10.1016/j.chroma.2011.08.004. Epub 2011 Aug 10.
3-Chloropropane-1,2-diol (3-MCPD) and 1,3-dichloro-2-propanol (1,3-DCP) were determined for the first time in bakery foods using pressurized liquid extraction (PLE) combined with in situ derivatization and GC-MS analysis. This one-step protocol uses N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) as silylation reagent. Initially, screening experimental design was applied to evaluate the effects of the variables potentially affecting the extraction process, namely extraction time (min) and temperature (°C), number of cycles, dispersant reagent (diatomaceous earth in powder form and as particulate matter with high pore volume Extrelut NT) and percent of flush ethyl acetate volume (%). To reduce the time of analysis and improve the sensitivity, derivatization of the compounds was performed in the cell extraction. Conditions, such as the volume of BSTFA, temperature and time for the in situ derivatization of analytes using PLE, were optimized by a screening design followed to a Doehlert response surface design. The effect of the in-cell dispersants/adsorbents with diatomaceous earth, Florisil and sodium sulfate anhydrous was investigated using a Box-Behnken design. Using the final best conditions, 1 g of sample dispersed with 0.1 g of sodium sulfate anhydrous and 2.5 g diatomaceous earth was extracted with ethyl acetate. 1 g of Florisil, as clean-up adsorbent, and 70 μL of BSTFA were used for 3 min at 70°C. Under the optimum conditions, the calibration curves showed good linearity (R(2)>0.9994) and precision (relative standard deviation, RSD≤2.4%) within the tested ranges. The limits of quantification for 1,3-DCP and 3-MCDP, 1.6 and 1.7 μg kg(-1), respectively, are far below the established limits in the European and American legislations. The accuracy, precision, linearity, and limits of quantification provided make this analytical method suitable for routine control. The method was applied to the analysis of several toasted bread, snacks, cookies and cereal samples, none of which contained chloropropanols at concentrations above the legislation levels.
3-氯-1,2-丙二醇（3-MCPD）和 1,3-二氯-2-丙醇（1,3-DCP）首次在烘焙食品中使用加压液体萃取（PLE）结合原位衍生化和 GC-MS 分析进行了测定。该一步法使用 N,O-双（三甲基硅基）三氟乙酰胺（BSTFA）作为硅烷化试剂。最初，采用筛选实验设计来评估可能影响萃取过程的变量的影响，即萃取时间（min）和温度（°C）、循环次数、分散剂（粉末形式的硅藻土和高孔体积的微粒状 Extrelut NT）和冲洗乙基乙酸酯体积的百分比（%）。为了缩短分析时间并提高灵敏度，在细胞萃取中对化合物进行了衍生化。通过筛选设计和 Doehlert 响应面设计优化了使用 PLE 原位衍生化分析物的 BSTFA 体积、温度和时间等条件。使用硅藻土、Florisil 和无水硫酸钠的细胞内分散剂/吸附剂的效果使用 Box-Behnken 设计进行了研究。使用最终最佳条件，将 1 g 样品与 0.1 g 无水硫酸钠和 2.5 g 硅藻土分散，用乙酸乙酯萃取。1 g Florisil 作为净化吸附剂，70 μL BSTFA 在 70°C 下使用 3 分钟。在最佳条件下，校准曲线在测试范围内表现出良好的线性（R(2)>0.9994）和精密度（相对标准偏差，RSD≤2.4%）。1,3-DCP 和 3-MCDP 的定量限分别为 1.6 和 1.7 μg kg(-1)，远低于欧洲和美国法规规定的限量。提供的准确性、精密度、线性和定量限使该分析方法适合常规控制。该方法应用于几种烤面包、小吃、饼干和谷物样品的分析，这些样品中均未检出氯丙醇，浓度均低于法规规定的水平。
