微波消解-电感耦合等离子体发射光谱(ICP-OES)法测生物质中的碱金属和碱土金属

为研究并解决测试生物质样品中碱金属和碱土金属含量的干扰,采用微波消解-电感耦合等离子体发射光谱(ICP-OES)法对生物质中的碱金属和碱土金属钾、钙、钠、镁元素进行测定,考察了样品消解后不同的酸体系,共存元素干扰对钾、钠、钙、镁含量测定的干扰研究。经过研究表明,接近分析标准曲线酸浓度的样品干扰小,铅、铟、钛、锰元素对钠元素测定造成干扰,砷、铜、镉对钙元素测定干扰,铝对钾元素测定有干扰,镁测定不受共存元素干扰影响,运用干扰系数法可以减少共存元素对测定元素的误差。各待测元素标准曲线相关系数大于0.9996,检出限为0.0014~0.023 mg/L,玉米芯各元素的相对标准偏差为0.98%~1.9%,加标回收率为80.2%~106%;西瓜皮的各元素相对标准偏差为0.91%~2.3%,加标回收率为85.3%~106%。方法用于测定国家标准物质GBW07603,各元素结果均在标准值参考范围内。方法用于测定生物质中碱金属和碱土金属的结果,用t检验法与离子色谱测定值进行比对,结果无显著性差异。

Determination of Alkali Metal and Alkaline Earth Metal Content in Biomass by ICP-OES with Microwave Digestion

In order to study and solve the interference of the content of alkali metals and alkaline earth metals in the biomass samples, microwave digestion ICP-OES is used to determine the alkali metals and alkaline earth metals potassium, calcium, sodium, and magnesium elements in biomass. Different acid systems after sample digestion and the interference of coexisting elements affects the content of potassium, sodium, calcium, and magnesium are analyzed.Studies have shown that samples close to the acid concentration of the analytical standard curve have little interference. Lead, indium, titanium, and manganese elements interfere with the determination of sodium, arsenic, copper, and cadmium interfere with the determination of calcium, and aluminum interferes with the determination of potassium. Magnesium determination is not affected by the interference of coexisting elements, and the use of interference coefficient method can reduce the error of coexisting elements on the determination of elements. The correlation coefficient of the standard curve of each test element is greater than 0.9996, the detection limit is 0.0014~0.0232 mg/L, the precision of each element of the corncob is 0.98%~1.89%, and the recovery rate of standard addition is 80.2%~106.4%; The precision of each element of the watermelon rind is 0.91%~2.25%, and the recovery rate of standard addition is 85.3%~106.3%. This method uses the national standard GBW07603, and the results of each element are within the reference range of the standard value. The t-test method was used to analyze the content of alkali metals and alkaline earth metals in biomass by ion chromatography, and there was no significant difference in the measurement and analysis methods without the interference of coexisting elements.