新型固体进样汞镉测定仪测定固体样品中的镉

使用由北京吉天仪器有限公司开发的新型固体进样汞镉测定仪(DCMA-200),对采集的土壤、大气颗粒物和固体废物样品中镉的浓度进行分析。在测试过程中,选择9种标准土(GBW07407、GBW07402、GBW07410、GBW07425、GBW07426、GBW07428、GBW07419、GBW07309和GBW07418),研究了进样量对测定的影响,并分别在1.0~10.0 mg称量范围内建立了标准曲线(R ²> 0.93)。当固体样品进样量为10.0 mg时,镉的检出限为0.004 7 mg/kg,测定下限为0.016 mg/kg。利用7种标准土(GBW07418和GBW07419除外)绘制的标准曲线,测得的5种实际土壤中镉的浓度与利用电感耦合等离子体质谱仪(ICP-MS)测得的结果较一致。但与ICP-MS测得的结果相比,利用该固体进样汞镉测定仪测得的大气颗粒物中镉的浓度明显偏高,而危险废物中镉的浓度偏低。因此,建议在检测某地区的固体样品时,尽可能选择该区域和该类固体样品的标准品来设计标准曲线,从而提高测试结果的准确性。

Determination of cadmium in solid samples using solid sampling atomic fluorescence spectrometry

The concentration of cadmium (Cd) in soils, atmospheric particles, and solid wastes was determined using a new solid sampling atomic fluorescence spectrometry (SSAFS), which was designed by Beijing Titan Instruments Co., Ltd. Nine standard soils(GBW07407, GBW07402, GBW07410, GBW07425, GBW07426, GBW07428, GBW07419, GBW07309 and GBW07418) were chosen to study the influence of sample mass on the measurements, and the standard curves were well fitted (R 2 > 0.93) in the range of 1.0-10.0 mg. When the sample mass was 10.0 mg, the detection limit and determination limit were 0.004 7 and 0.016 mg/kg, respectively. The concentration of Cd in five field samples measured with SSAFS using the seven standard curves (except GBW07418 and GBW07419) was consistent with the value measured with the inductively coupled plasma mass spectrometry (ICP-MS). However, compared with the concentration of Cd determined by ICP-MS, the concentration in atmospheric particles determined by SSAFS was much higher, and the value in solid wastes was smaller. As a result, in order to improve the accuracy of data, it was suggested that the same type of standards or standards in the studied area should be used to establish the standard curves before analyzing solid samples in some area.