食品纸塑复合包装材料中汞含量测定条件的优化

Determination of mercury content in the food paper-plastic composite packaging materials

采用湿法消解—原子荧光法对食品纸塑复合包装材料中汞的含量进行测定,并对检测条件进行优化。采用10mL浓硝酸,2mL双氧水,消解4h可以将0.500 0g食品纸塑复合包装材料消解完全。优化得出原子荧光光度计测定汞的最佳仪器条件为：负高压210V,屏蔽气流量900mL/min,载气流量500mL/min,注入量0.5mL,灯（Hg）电流10mA,原子化器高度10mm,读数时间10s,延迟时间1.0s;选择载流介质为5%盐酸,硼氢化钾溶液和氢氧化钾溶液的浓度均为5g/L。汞在0.0-20.0ng/mL范围内呈现良好的线性关系,相关系数为0.999 6,测定汞的检出限为0.002 5μg/mL,回收率为95.93%-97.38%,相对标准偏差为3.02%-3.85%。该方法具有精密度高,检出限低,准确度高等优点,适用于食品纸塑复合包装材料中汞的含量的检测分析。

A method for determining mercury content in the food paper-plastic composite packaging materials with wet digestion-atomic fluorescence spectrometry was developed.The sample of 0.500 0g with 10 mL of concentrated nitric acid and 2mL of hydrogen peroxide digestion 4hcould get the best results.The best optimized atomic fluorescence spectrometer detection conditions of mercury were as followed：a negative high voltage of 210 V,the shielding gas flow rate of 900mL/min,the carrier gas flow rate of 500mL/min,injection volume of 0.5mL,the Hg lamp current of 10 mA,the atomizer height of 10 mm,reading time of 10 s,the delay time of 1.0s,carrier medium for the 5% hydrochloric acid,potassium borohydride solution and the concentration of the potassium hydroxide solution5g/L.Mercury showed a good linear relationship in the range of 0.0to 20.0ng/mL with a correlation coefficient of 0.999 6,and the detection limit was 0.002 5μg/mL.The recoveries of mercury range from 95.93% to 97.38%,and the relative standard deviations of mercury ranged from 3.02%to 3.85%.The method has the advantages of high precision,low detection limit and high accuracy,and it is applicable to detection and analysis of mercury content in food paper-plastic composite packaging materials in the market.