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目的建立用浊点萃取-火焰原子吸收光谱法测定食品接触塑料制品浸泡液中痕量铅的方法。方法以二硫腙为络合剂,TritonX-100非离子表面活性剂为萃取剂,对3种塑料制品(保鲜膜、塑料吸管和塑料瓶盖)浸泡液中的铅进行萃取富集,然后用火焰原子吸收光谱法测定其中铅的含量,详细考察了平衡温度、平衡时间、络合剂用量、溶液pH值、表面活性剂TritonX-100用量、磷酸二氢钾-氢氧化钠体系缓冲溶液用量、离心时间等因素对萃取率的影响。结果在优化条件下,检测线性范围为0.01 mg/L~1.00 mg/L,检出限为0.07μg/L,使用该方法检测3种塑料制品浸泡液中铅的含量,回收率在95.4%~101.8%之间,相对标准偏差(RSD)为2.04%~3.46%。结论该法灵敏度高、操作简便、快速,适用于塑料样品中痕量铅的测定。
Objective To establish a method for the determination of trace lead in food contact plastic products by cloud point extraction - flame atomic absorption spectrometry. Methods Dithizone as complexing agent and TritonX-100 non-ionic surfactant as extractant were used to extract and enrich the lead in three kinds of plastic products (plastic wrap, plastic pipette and plastic bottle cap) Flame atomic absorption spectrometry was used to determine the content of lead. The equilibrium temperature, equilibration time, the amount of complexing agent, the pH value of the solution, the amount of surfactant TritonX-100, the amount of buffer solution of potassium dihydrogen phosphate-sodium hydroxide system, Centrifugal time and other factors on the extraction rate. Results Under the optimized conditions, the linear range of detection was 0.01 mg / L ~ 1.00 mg / L with the detection limit of 0.07 μg / L. The method was used to determine the lead content in the soaking solution of three kinds of plastic products. The recoveries ranged from 95.4% 101.8%, the relative standard deviation (RSD) was 2.04% ~ 3.46%. Conclusion The method has high sensitivity, easy operation and fastness and is suitable for the determination of trace lead in plastic samples.