石墨炉原子吸收光谱法测定土壤中铅镉的条件优化

Optimization of conditions for determination of lead and cadmium in soil by Graphite Furnace Atomic Absorption Spectrometry

采用电热板加热四酸消解法、微波消解法、全自动石墨体加热消解法三种不同前处理方法,美国热电公司ICE-3400AA原子吸收分光光度计石墨炉法测定土壤样品中的铅、镉含量,通过对铅、镉的干燥温度,灰化温度,原子化温度的优化选择,确定了测定铅镉的最佳石墨炉程序,通过加不加基体改进剂对比测试,确定了添加磷酸氢二铵基体改进剂可以有效提高土壤样品测试结果的精密度。测定铅的最佳实验条件是磷酸氢二铵作为改进剂,干燥温度100℃,灰化温度为650℃,原子化温度为1300℃,测定镉的最佳实验条件是磷酸氢二铵作为改进剂,干燥温度130℃,灰化温度为700℃,原子化温度为1 100℃。三种前处理方法,全自动石墨体加热消解法费时最少,精密度最佳。

Using three different pretreatment methods:electrothermal plate heating four acid digestion method,microwave digestion method,and graphite digestion method,determination of Lead and Cadmium in Soil Samples by Graphite Furnace Spectrophotometer ICE-3400AA Atomic Absorption Spectrophotometer,The optimum graphite furnace procedure for the determination of lead and cadmium was determined by optimizing the drying temperature,ash temperature and atomization temperature of lead and cadmium.The precision of soil sample test results can be improved by adding hydrogen diammonium phosphate matrix modifier through the comparison test.The best experimental condition for the determination of lead is ammonium hydrogen phosphate as an modifier,drying temperature is 100°C,ash temperature is 650°C,and atomization temperature is 1300°C.The best experimental condition for the determination of cadmium is ammonium hydrogen phosphate as an modifier.,drying temperature 130°C,The ash temperature is 700°C and the atomization temperature is 1100°C.Three pretreatment methods,fully automatic graphite digestion method is the least time-consuming,the best precision.