食品中磷国标检测方法的研究与改进

Research and improvement of national standard detection method for phosphorus in food

中文关键词:  食品  磷  分光光度法  微波消解

英文关键词:food  phosphorus  spectrophotometric method  microwave digestion

中文摘要:

      目的 建立简单、高效的微波消解-分光光度法测定食品中的磷, 有效减少有毒试剂的使用量, 缩短实验时长, 提高检测灵敏度。方法 取0.1 g样品, 加8 mL硝酸微波消解, 温度曲线为0~15 min匀速升温到190 ℃并保持15 min, 消解完毕后160 ℃赶酸并用纯水定容至50 mL, 取标准系列及2 mL样品于25 mL比色管, 与2.5 mL硫酸(5%)、2 mL钼酸铵溶液(50 g/L)、1.0 mL氯化亚锡-硫酸肼溶液显色20 min后, 在660 nm波长处用1 cm比色杯比色定量。结果 实验回收率为98%, 加标样品相对标准偏差为2.65%, 符合实验室质量控制规范的相关要求。结论 改善后的方法具有精密度高、检出限低、空白值低且操作步骤简单, 耗时较少的优点。

英文摘要:

      Objective To establish a simple and efficient microwave digestion-spectrophotometry method for the determination of phosphorus in food, which can effectively reduce the amount of toxic reagents, shorten the experimental time and improve the detection sensitivity. Methods 0.1 g sample was digested with 8 mL nitric acid under microwave, the temperature curve was 0-15 min, the temperature was raised to 190 ℃ at a constant speed and kept for 15 min. After digestion, the acid was removed at 160 ℃ and the volume was fixed to 50 mL with pure water. The standard series and 2 mL sample were taken into a 25 mL colorimetric tube, developed the color with 2.5 mL sulfuric acid (5%), 2 mL ammonium molybdate solution (50 g/L), and 1.0 mL stannous chloride-hydrazine sulfate solution for 20 min, and quantified with a 1 cm colorimetric cup at 660 nm wavelength. Results The experimental recovery rate was 98%, relative standard deviation of spiked samples was 2.65%, which met the relevant requirements of laboratory quality control standards. Conclusion The improved method has the advantages of high precision, low detection limit, low blank value, simple operation steps and less time consumption.