勘查地球化学找矿中重要指示元素的野外快速分析法(二)银的分析方法

发展了一种可在野外快速测定0.010-50μg/g银量的新方法.此法由两个各自独立而又配套的部分组成.一是直接测定0.25-50μg/g银量的Ag-TMK-SDS三元络合物光导比色测定法;二是测定0.010-0.25μg/g银量的巯基棉分离富集微珠析出比色法.可在同一份试液中依次完成.前者检出限为0.006μg/ml(K=3);测定铜、铅和锌矿石标样GSO-Cu-1(含银3.87μg/g)、GSO-Ph-1(含银14.7μg/g)和GSO-Zn-1(含银13.5μg/g)中的银,RDS(n=11)分别为1.6%、3.7%和3.4%;后法可检出5ng/g银;测定地球化学标样GSD-3(含银0.59μg/g)中的银,RSD(n=11)为6.t%.方法较为简便、快速、准确和灵敏.用光导比色计测定,结果准确度、精度均有较大改善,且与室内原子吸收法相当.故所定方法具有广阔的应用前景.

RAPID FIELD ANALYTICAL METHODS FOR IMPORTANT INDICATOR ELEMENTS IN GEOCHEMICAL EXPLORATION: (Ⅱ) ANALYTICAL METHOD OF SILVER

A new method has been developed for rapid field determination of 0. 010-50μg-g silver. The method consists of two independent yet correlated parts: one is Ag-TMK-SDS tribasic complex light-guide colorimetric determination methood for directly determining 0. 25-50μ/g silver,and the other is mercapto group isolation and enrichment micrcbead-separating colorimetry for determining 0. 010-0. 25μg/g silver. These two parts can be comploted successively in the same test liquid.The former has a detection limit of 0. 006μg/ml (k= 3), and for determining silver in copper, lead and Zinc standard ore samples GSO-Cu-1 (containing silver 3. 81μg/g), GSO-Ph- 1 (containing silver 14.7μg/g) and GSO-Zn-1 (containing silver 13. 5μg/g), RSD(n =11) values are 1.6%, some 3.7%and 3. 4 % respectively; the latter can detect 5 ng/g silver, and for determining silver in geochemical standard sample GSD-3 (containing silver 0. 5μg/g), RSD (n=11) is 6. 6 %. Tee method is fairly simple, convenient, accurate and sensitive. With a light-guide colorimeter, the determinations are remarkably improved in accuracy and precision, being equivalent to results obtained by atomic absorption method, and this suggests that the method has a bright future ill application.