不锈钢管原子化-原子吸收光谱法测定镁钙锶钡

Determination of magnesium,calcium,strontium,barium by atomization in stainless steel tube——atomic absorption spectrophotometry

提出一种无焰原子吸收光谱法测定4种碱土金属（Mg，Ca，Sr，Ba）的方法。方法基于将试液定量滴加在火焰原子吸收分光光度计火焰上方的特制不锈钢原子化管内，利用火焰高温加热不锈钢管，使碱土金属元素在不锈钢管内进行原子化并加以测定。在无火焰条件下进行原子化，避免了碱土金属的电离效应和克服了火焰本身发射光谱以及其对光源辐射线吸收所产生干扰。本法的原子化装置简单，不需要大量去离子水输送试液，试剂用量和废液排放少，适用于碱土金属元素（Ca，Mg，Sr，Ba）的测定，方法的特征质量为5．2×10^-12～9．5×10^12g／1％，检出限为5．0×10^12～9．3×10^12g。对矿泉水中Mg，Ca，sr，Ba的测定，相对标准偏差为0．1％～0．32％，加标回收率为99．0％～99．3％。

A method for determining the alkaline earth metals elements（Mg, Ca, Sr, Ba） by the nonflame atomic absorption spectrophotometry is proposed. The test solution is dropped into a specially prepared stainless steel atomizing tube on top of the flame atomic absorption spectrophotometer. The stainless steel atomizing tube is heated by the high temperature of the flame to make alkaline earth metals elements atomizing and being measured. Atomization under non-flame can avoid the ionization effect of alkaline earth metals elements and overcome the interference from emission spectrum of flame itself and absorption of radiation line of light source produced by flame. The atomizing device of the method is simple. It need not using much de-ionized water to deliver the test solution. The dosage of reagent and discharge of the waste solution are little. The method is suitable for determining the alka- line earth metals elements（Mg, Ca,Sr,Ba） with the characteristic mass of 5.2×10^12-9.5× 10^-12 g/1% and the detection limits of 5.0×10^-12-9. 3×10^-12 g. It has been applied to the determination of Mg, Ca, Sr, Ba in mineral water samples, giving recoveries of 99.0%--99.3% and RSD of 0.15%--0. 32%.