固体直接进样-原子荧光法测定土壤中的镉

采用固体进样原子荧光镉分析仪测定土壤中的镉无需进行样品的消解前处理,避免了元素损失,提高了检测效率。研究表明,采用Pauwels公式和相对均匀度因子(HE)估算实际样品的最小取样量在3 mg前提下,研磨粒径小于0.3 mm(60目)即可满足仪器微量进样要求;采用归一化方法得出干燥灰化功率为50 W、30 s,70 W、40 s,仪器的Ar-H2(9∶1,V/V)载气流量为800 m L·min~(-1)时,仪器检出限为0.016 ng、方法检出限为0.005 3 mg·kg~(-1),试验验证相对标准偏差小于10%,分析时间小于3 min,且与ICP-MS法测定结果无显著性差异(P0.05)。该仪器检测方法操作简便、耗时短,适用于田间土壤中Cd的分析测定。

Determination of cadmium in soil by using direct solid sampling-atomic fluorescence spectrometry method

The current methods for determining soil cadmium(Cd) require complicated pretreatments. Here we developed a method to determine soil Cd by using solid sample-atomic fluorescence spectrometry. The method avoided element loss and improved the analysis efficiency. Estimates by the Pauwels formula and Homogeneity(H_E) showed that minimum of 3 mg sample with particle size less than 0.3 mm(60 mesh) met the trace sampling requirements of the instrument. The power and time of sample drying were 50 W and 30 s, and those for sample ashing 70 W and 40 s, respectively. The Ar-H₂(9:1, V/V) flow rate was controlled at 800 mL·min-1. The instrument detection limit and method detection limit were 0.016 ng and 0.005 3 mg·kg^-1, respectively, with the relative standard deviations less than 10%. The analysis time was less than 3 min. The results obtained by the present method was not significantly different(P >0.05) from those of ICP-MS. In conclusion, the present method is quick, simple, and sensitive, and can meet the requirements of cadmium determination in soils.