酸溶-电感耦合等离子体原子发射光谱法测定白云石和菱镁石中主次元素

Determination of Major and Minor Elements in Dolomite and Magnesite by Inductively Coupled Plasma Emission Spectrometry with Acid Dissolution

为解决白云石和菱镁石元素测定前处理过程总固体溶解量高的问题,利用酸溶前处理样品,通过研究酸体系、温度及消解方式对试样消解的影响,建立了酸溶-电感耦合等离子体原子发射光谱(ICP-AES)法测定白云石和菱镁石中铝、钙、铁、镁、锰、磷、硅、锶的方法。结果表明,使用5 mL盐酸和硝酸混合酸(1+3)-0.75 mL氢氟酸-5 mL水以密闭消解的方式,在150℃下消解白云石和菱镁石30 min,并以2 mL饱和硼酸络合多余的氢氟酸,可以得到澄清消解液。通过考察白云石和菱镁石中铝、钙、铁、镁、锰、磷、硅、锶的谱线干扰情况,选择Al 308.215 nm、Ca 318.127 nm、Fe 261.187 nm、Mg 277.983 nm、Mn 257.61 nm、P 213.618 nm、Si 251.611 nm、Sr 421.552 nm作为分析线,各元素的校准曲线在线性范围内线性关系良好,相关系数均不小于0.999。按照实验方法测定白云石和菱镁石标准物质,各元素结果的相对标准偏差(RSD,n=6)为0~3.2%,测定值与认定值无显著性差异。方法有效解决了白云石和菱镁石快速有效溶解及准确测定问题,同时避免了大量熔剂带来的堵塞和干扰。

To solve the problem of high total solid solubility in the pretreatment process of element determination of dolomite and magnesite,samples were treated with acid before dissolution,and the influence of acid system,temperature and digestion method on sample digestion was studied.A determination method of aluminum,calcium,iron,magnesium,manganese,phosphorus,silicon and strontium in dolomite and magnesite was established by inductively coupled plasma atomic emission spectrometer(ICP-AES)with acid dissolution pretreatment.The results showed that,dolomite and magnesite were digested with 5 mL hydrochloric acid-nitric acid mixed acid(1+3)-0.75 mL hydrofluoric acid-5 mL water in closed digestion at 150℃for 30 min,and the excess hydrofluoric acid was complexed with 2 mL saturated boric acid,clarifying solution could be obtained.The spectra interference of aluminum,calcium,iron,magnesium,manganese,phosphorus,silicon,strontium in dolomite and magnesite was investigated.Al 308.215 nm,Ca 318.127 nm,Fe 261.187 nm,Mg 277.983 nm,Mn 257.61 nm,P 213.618 nm,Si 251.611 nm,Sr 421.552 nm were selected as analytical line.The linearity of calibration curves in linear range was good for all elements,and the correlation coefficients were all greater than 0.999.The standard substances of dolomite and magnesite were determined according to the experimental method,the relative standard deviation(RSD,n=6)of the results were between 0—3.2%,and the found results were consistent with the certified values.This method rapidly and efficiently dissolves dolomite and magnesite with accurate results,and also avoids the blockage and interference caused by a large amount of flux.