Determination of Boron, Germanium, Bromine, Molybdenum, Tin, Iodine and Tungsten in Geochemical Survey Samples by ICP-MS with Alkali Fusion-Cation Exchange Resin Separation

Abstract

BACKGROUND Multi-target geochemical mapping is one of the most important basic regional tasks in multi-target regional geochemical surveys. In order to better reflect changes in the geochemical background, analytical methods are required to have higher accuracy and precision, and lower detection limits. Elements B, Ge, Br, Mo, Sn, I, and W in geochemical survey samples are mainly prepared and determined by smelting ore individually or in groups. The analysis procedure is long and involves 6 methods. OBJECTIVES In order to integrate 6 supporting analysis methods, optimize analysis conditions, and improve the accuracy and precision of the method. METHODS The mixed reagent of sodium peroxide and sodium hydroxide was used for alkali fusion. Citric acid was added to the solution. Cation exchange resin was used for static exchange for 2-3 hours to remove a large amount of cations in the solution and reduce matrix interference. B, Ge, Br, Mo, Sn, I, and W were determined using inductively coupled plasma mass spectrometry. RESULTS The detection limits of B, Ge, Br, Mo, Sn, I, and W were 0.66, 0.096, 0.78, 0.11, 0.15, 0.29, and 0.27μg/g, respectively. Relative standard deviation (RSD, n=12) was between 2.1% and 7.5%, which were all less than 10%. CONCLUSIONS The method is simple, rapid and low-cost, and its precision and accuracy meet the requirements of 《Specification of multi-purpose regional geochemical survey (1:250000)》 (DZ/T 0258-2014). It can quickly and accurately determine B, Ge, Br, Mo, Sn, I, W in geochemical survey samples in a thick coverage area.

Keywords

• geochemical survey samples
• sodium peroxide-sodium hydroxide alkali fusion
• citric acid
• cation exchange resin
• inductively coupled plasma-mass spectrometry