黄原脂棉分离-石墨炉原子吸收光谱法测定咸味食品中Pb^(2+)

Determination of Trace Lead in Salty Foods by GFAAS after Cotton Cellulose Xanthate Separation

利用单因素试验对黄原脂棉吸附溶液中Pb^(2+)的条件进行了实验优化,结果显示:在pH=5.0的溶液体系中,于温度20℃,振荡吸附15min,黄原脂棉对Pb^(2+)的吸附效果最佳;吸附的Pb^(2+)用6.0mL 3.0mol/L HCl,于40℃下解吸15min,可将Pb^(2+)从黄原酯棉上完全洗脱。采用石墨炉原子吸收光谱法,将该条件用于测定咸味食品中痕量Pb^(2+),结果表明:黄原脂棉能有效消除盐类基体给测定Pb^(2+)带来的干扰,方法的相对标准偏差为1.56%~2.31%(n=6);回收率为97.0%~102.7%;检出限为0.047mg/kg。本法灵敏、准确、可靠,可用于咸味食品中痕量Pb^(2+)的测定。

In this paper,the adsorption and desorption of lead between aqueous solution and cotton cellulose xanthate（CCX）were studied by single factor experiment method.The results showed that lead within aqueous solution could be enriched quantitatively under the conditions of pH=5.0,adsorption temperature 20 ℃ and adsorption time 15 minutes with CCX,and lead adsorbed on CCX could be desorbed with 6.0 mL（3.0 mol/L）solution of hydrochloric acid under the conditions of desorption temperature 40 ℃ and desorption time 10 minutes.Trace lead contents in salty food samples were determined by graphite furnace atomic absorption spectrophotometry after cotton cellulose xanthate separation.The relative standard deviations（RSD）of the method were in the range of 1.56%-12.31%（n=6）.The recoveries of samples were in the range of 97.0%-102.7%.The detection limit of lead was0.047 mg/kg.The method is suitable for the determination of trace lead in salty foods,with good precision and high accuracy.