不同前处理方法对秸秆金属元素原子吸收光谱分析结果的影响

秸秆中金属元素是关系农作物秸秆科学利用的重要组成部分,目前还没有统一的秸秆中金属元素原子吸收光谱(atomic absorption spectroscopy,AAS)测定方法标准,该研究采用原子吸收光谱测定黄芪(GBW10028)标准物质、玉米秸秆、小麦秸秆和棉花秸秆中金属元素含量,比较了不同前处理方法对样品中K、Cu、Fe、Zn和Mg分析结果的影响。结果表明:微波消解、干法灰化和湿法消解测定黄芪(GBW10028)标准物质中金属元素含量差异性显著(P<0.05),微波消解比干法灰化、湿法消解准确度高。微波消解对玉米秸秆、小麦秸秆和棉花秸秆中各金属元素的影响与黄芪(GBW10028)标准物质趋于一致。微波HNO3与微波HNO3-H2O2测定结果差异性不显著(P>0.05),微波HNO3比微波HNO3-H2O2和微波HNO3-H2SO4测定结果稳定。微波HNO3是进行秸秆样品金属元素含量测定时较准确简便的前处理方法。

Effects of different pretreatments on analysis results of atomic absorption spectroscopy by metal elements in straw

Mental elements play important roles in the scientific utilization of crop straw. There is currently no standard method for determination of metal elements in straw. This article investigated the effects of different pretreatments on the determination of K, Cu, Fe, Zn and Mg in Astragalus mongholicus reference material (GBW10028), corn straw, wheat straw and cotton stalk by atomic absorption spectroscopy. The experimental results showed that microwave digestion, dry ashing and wet digestion had significant differences (P<0.05) on the content of metal elements in Astragalus mongholicus reference material (GBW10028). Microwave digestion had a higher precision and accuracy than dry ashing and wet digestion. Microwave digestion had the same effect on determination of metal elements of Astragalus mongholicus reference material (GBW10028), corn straw, wheat straw and cotton stalk. Microwave HNO3 and microwave HNO3-H2O2 pretreatments had no significant difference (P>0.05), microwave HNO3 pretreatment was more stable than microwave HNO3-H2O2 and microwave HNO3-H2SO4 pretreatments. Microwave HNO3 pretreatment was a more accurate and simple method for the determination of metal elements in straw.