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目的建立N-甲基吡咯烷酮直接溶解-石墨炉原子吸收法快速测定植物油中镉的方法。方法称取1 g植物油样品,经N-甲基吡咯烷酮溶解并定容至10 ml,涡旋振荡形成微乳液后,以纳米胶体钯为基体改进剂,纯水溶液作标准曲线,用石墨炉原子吸收光谱法测定微乳液中镉的浓度。结果镉在0.025μg/L~2.0μg/L浓度范围内线性关系良好,相关系数为0.999 4,最低检出限为0.25μg/kg,回收率为85.9%~98.2%,相对偏差<5%。应用此方法对大豆油、花生油、菜籽油、调和油进行加标回收和精密度实验,回收率均>85.0%,相对偏差均<5%,与其他前处理方法比较,结果偏差<5%。结论该方法简便快速、灵敏度高、重现性好,适用于各类型植物油中微量镉的快速批量测定。
Objective To establish a rapid method for the determination of cadmium in vegetable oil by N-methylpyrrolidone direct dissolution-graphite furnace atomic absorption spectrometry. Methods Weigh 1g vegetable oil sample, dissolve and dilute to 10ml with N-methylpyrrolidone, vortex to form a microemulsion, use nano-colloidal palladium as matrix modifier, pure water as standard curve, use graphite furnace atomic absorption Spectrophotometric Determination of Cadmium in Microemulsion. Results The calibration curve was linear over the range of 0.025μg / L ~ 2.0μg / L with a correlation coefficient of 0.999 4 and a minimum detectable limit of 0.25μg / kg. The recoveries ranged from 85.9% to 98.2%. The relative deviation was less than 5%. The recovery rate and precision of soybean oil, peanut oil, rapeseed oil and blending oil were all 85%, the relative deviation were less than 5%. Compared with other pretreatment methods, the deviation of the results was less than 5% . Conclusion The method is simple, rapid, sensitive and reproducible. It is suitable for the rapid determination of trace cadmium in vegetable oils of various types.