快速协同浊点萃取-荧光分光光度法测定5种食品塑料包装材料中的浸出苯酚

建立快速协同浊点萃取-荧光分光光度法测定食品塑料包装材料中浸出苯酚的方法。以直链型的非离子表面活性剂聚乙二醇6000为萃取剂,正辛醇作浊点的诱导协同剂,与无水硫酸钠共同作用将聚乙二醇6000浊点温度降至室温(约20 ℃),整个实验过程仅需3 min,并对影响苯酚萃取率的因素(聚乙二醇6000、无水硫酸钠和正辛醇的用量、溶液pH)进行考察。结果表明,溶液pH6.0、0.2 g/mL聚乙二醇6000 8.0 mL、无水硫酸钠3.0 g及正辛醇5.0 mL的萃取效果最佳。苯酚在0.02~1.60 μg/mL范围内线性良好,R²为0.9998,检出限为0.0064 μg/mL,相对标准偏差为4.49%(n=8)。对于50 mL的样品溶液,苯酚萃取率可达89.8%,加标回收率为90.5%~109.5%。5种食品塑料包装材料中,只有样品2检出苯酚0.0310 μg/mL,但未超标,其它4种塑料包装材料均未检出。该方法简便、快速、省时、灵敏度高,适用于食品塑料包装材料中浸出苯酚的测定。

Determination of Phenol in Five Food Plastic Packaging Materials by Rapid Synergistic Cloud Point Extraction Coupling with Fluorescence Spectrophotometry

A rapid synergistic cloud point extraction method coupling with fluorescence spectrophotometry was developed for preconcentration and determination of trace amounts of phenol from food plastic packaging materials. The linear-chain and non-ionic surfactant polyethylene glycol 6000 was selected as the extractant. The octanol was used as a cloud point revulsant and synergistic reagent with anhydrous sodium sulfate to lower the cloud point temperature of polyethylene glycol 6000 to room temperature (about 20℃) within 3 min. The factors influencing the extraction efficiency of phenol, including the mass concentration of PEG 6000, the mass of anhydrous sodium sulfate, the volume of octanol, and the pH of solution were optimized. As a result, the optimum conditions for extraction of phenol were as follows:the pH of solution 6.0;0.2 g/mL PEG 6000 8.0 mL;mass of anhydrous sodium sulfate 3.0 g and volume of octanol 5.0 mL. Under these conditions, a good linearity (R2=0.9998) was obtained in the range of 0.02~1.60 μg/mL with the limit of detection of 0.0064 μg/mL. The method also showed excellent repeatability in the view of low relative standard deviation (RSD=4.49%, n=8) and obtained high extraction efficiency (89.8%) in a 50 mL sample. The recoveries were between 90.5%~109.5%. Only sample 2 of five kinds of food plastic packaging materials was found to contain phenol 0.0310 μg/mL, which did not exceed the standard, and the other four materials were not detected to contain phenol. This method was simple, rapid, time-saving and sensitive. It was successfully applied to determinate phenol in five food plastic packaging materials.