HNO_(3)-H_(2)O_(2)消解体系对植物中磷和钾元素的快速定量分析

Rapid quantification analysis of plant phosphorus and potassium using HNO_(3)-H_(2)O_(2)digestion system

为研究不同酸溶消解体系对植物样品中磷、钾测定的影响,分别采用H_(2)SO_(4)-H_(2)O_(2)、HNO_(3)-HClO_(4)、HNO_(3)-H_(2)O_(2)和王水-H_(2)O_(2)等4种酸体系对灌木枝叶标准物质(GBW07603)进行酸溶消解处理,使用电感耦合等离子体发射光谱仪(ICP-OES)测定其中磷、钾的含量,筛选最优的酸溶消解体系.结果表明,HNO_(3)-H_(2)O_(2)消解法对植物样品消解彻底且消解后溶液澄清,测定结果的准确度和精密度最高,安全性好,是最佳消解体系.加酸量±10%对HNO_(3)-H_(2)O_(2)消解法测定磷、钾元素含量结果没有显著影响,但消解温度对其影响较大,最适消解温度为150—180℃.在最优条件下,磷的检出限和测定限分别为0.004 g·kg^(−1)和0.018 g·kg^(−1);钾的检出限和测定限分别为0.06 g·kg^(−1)和0.25 g·kg^(−1);对8种不同植物标准物质中磷和钾测定值均在标准值范围内,且相对标准偏差和相对误差都小于±5%;对4种不同植物标准物质的加标回收率在91%—106%之间.因此,HNO_(3)-H_(2)O_(2)消解结合ICP-OES测定方法能满足不同植物的测定要求,可用于大批量样品的快速检测分析.

To study effects of different acid digestion systems on plant phosphorus and potassium determination,four acid systems,including H_(2)SO_(4)-H_(2)O_(2),HNO_(3)-HClO_(4),HNO_(3)-H_(2)O_(2)and aqua regia-H_(2)O_(2),were selected to digest certified reference materials of shrub branches and leaves(GBW07603).Phosphorus and potassium in digested extracts were determined using an inductively coupled plasma emission spectrometer(ICP-OES)by which the optimal acid digestion system was consequently chosen based on accuracy and precision.It was observed that HNO_(3)-H_(2)O_(2)system digested plant samples completely and the digested extracts were clear.Results of ICP-OES analysis showed the highest accuracy and precision.With the safety property of HNO_(3)-H_(2)O_(2),it could be concluded that it is optimal.The difference in concentrations of phosphorus and potassium determined between treatments with acid addition ranged±10%was insignificant.However,the digestion temperature had significant impact on the determined concentrations.The optimal digestion temperature was 150-180℃.Under optimal digestion conditions,the detection and determination limits of phosphorus were 0.004 g·kg^(−1)and 0.018 g·kg^(−1),respectively,while 0.06 g·kg^(−1)and 0.25 g·kg^(−1)for potassium,respectively.Determination values for 8 various plant reference materials were all within the standard range,with relative bias and errors less than±5%.The recovery values of added standards for 4 various plant reference materials ranged 91%-106%.Therefore,HNO_(3)-H_(2)O_(2)combining with ICP-OES determination can satisfy the analysis of phosphorus and potassium in various plants and fits for quick quantification of samples with large quantities.