湿法消解–石墨炉原子吸收标准加入法测定土壤中的镉

Determination of Cadmium in Soil by Mixed Acid Digestion and Graphite Furnace Atomic Absorption Spectrometry Standard Addition Method

土壤样品经过硝酸–氢氟酸于130℃加热回流处理后,采用石墨炉原子吸收标准加入法测定半消解样品中镉的含量.以5% 氯化铵或0.1% 硝酸钯作为化学改进剂,灰化温度为500℃、原子化温度为2 000℃.当标准系列吸光度在0.18 以内时,镉标准溶液的质量浓度在0-3.0 μg/L 内与吸光度呈良好的线性,相关系数r=0.998 6,方法的检出限为0.02 mg/kg,实际样品测定结果的相对标准偏差为3.93%～5.30% （n=5）.用该法与国标方法对土壤标准样品进行测定,两种方法测定结果一致.该法快速、简便,适用于土壤中镉含量的快速检测.

Soil was semi-digested with HNO3–HF by heating reflux at 130℃ , the content of cadmium in the samplesolution was determined by graphite furnace atomic absorption spectrometry（GFAAS）, 5% ammonium chloride or 0.1%palladium nitrate was used as matrix modifier. The GFAAS ashing temperature was 500℃ and the atomization temperaturewas 2 000℃. Linear relationship between absorbance and mass concentration of cadmium was obtained in the range of 0–3.0μg/L within the absorbance value less than 0.18, the correlation coefficient was 0.998. The detection limit of the methodwas 0.02 mg/kg, the relative standard deviation of samples detection results was 3.93%–5.30% （n=5）. Three standardsoil samples were detected by this method and national standard method, the results of two methods were consistent. Themethod is rapid and simple,it is suitable for rapid determination of cadium content in soil.