火焰原子吸收光谱法测定植烟土壤中的速效钾

Determination of Available Potassium in Tobacco Planting Soil by Flame Atomic Absorption Spectrometry

利用1 mol/L乙酸铵溶液提取土壤中的速效钾,然后用火焰原子吸收光谱法测定,建立了一种方便、快捷测定植烟土壤中速效钾的方法。结果表明:①土壤粒度对提取效率影响不大,最佳提取条件为:以1 mol/L乙酸铵溶液为提取剂,土壤质量和提取剂体积比为1∶20,振荡提取120 min。②乙酸铵溶液对钾的测定有一定的增敏作用,用1 mol/L乙酸铵溶液配制标准母液,然后再逐级稀释配制系列标准溶液。③方法的检出限为0.018 g/kg,相对标准偏差为3.81%(C=0.7 mg/L,n=10);方法用于土壤有效态成分分析标准物质的测定,实验结果在推荐值的误差范围之内。该方法适用于批量植烟土壤样品中速效钾的测定。

A convenient and fast method for determining available potassium in tobacco planting soil with flame atomic absorption spectrometry was developed, in which available potassium was extracted from soil samples with 1 mol/L ammonium acetate solution. The results showed that： 1） The effect of soil granularity on extracting efficiency was negligible, the optimal extracting conditions were： 1 mol/L ammonium acetate solution as extracting solvent, the rate of soil weight to extracting solvent volume 1：20, shaking for 120 minutes. 2） Ammonium acetate solution could enhance the atomic absorption degree of potassium, ammonium acetate of 1 mol/L was prepared as a standard mother solution, then a series of standard solution was prepared by the stepwise dilution of the standard mother solution. 3） The limit of detection of the method was 0.018 g/kg with the relative standard deviation of 3.83% （C=0.7 mg/L, n=10）. The analytical standards of soil available nutrients determined by this method were within the error range of reference value. The method was suitable to the determination of batches of tobacco planting soil samples.