METHOD OF THE SILICON IN WATER CONCENTRATION DETERMINATION Russian patent published in 2018 - IPC G01N30/00 

FIELD: measurement technology.

SUBSTANCE: invention relates to determination of the silicon in water concentration, namely, to the silicon determination in the presence of humic substances, and can be used in the underground and surface waters cleaning of silicon technology for both technical and drinking purposes. Claimed method for determining of the silicon in water concentration is that two samples of water are taken and mixed. First sample is divided into two parallel samples of the same volume. For the first sample, the following actions are taken: a) addition to each parallel sample of 1 cm³ of hydrochloric acid solution with a concentration of 5 mol/dm³ and 2.5 cm³ of ammonium molybdate solution with a concentration of 5 %, stirring and holding for 10 minutes, then adding 2.5 cm³ of tartaric acid solution with a concentration of 10 %, stirring and after 10–15 minutes; b) measuring the each parallel sample solution optical density at a wavelength of 410 nm in cuvets with a layer thickness of 1 cm relative to distilled water poured into a comparison cuvet; c) measuring the blank sample optical density, which is 25 cm³ of distilled water, having previously performed steps a) and b); d) determination of silicon mass concentrations in two parallel samples by the formulas: , , where D₁ and D₁' are values of the first and second parallel samples solutions optical density; D₀ is the blank sample solution optical density value; Σ is extinction coefficient, l/mole⋅cm; V_pr is the sample aliquote volume taken for analysis, cm³; 25 is the flask volume, cm³; 28,000 is the silicon molar mass, mg/mol; C₁ and C₁' are silicon mass concentrations in parallel samples, mg/dm³, the definition of the silicon C₁ and C₁' mass concentrations arithmetic average C_1.1. Second sample of water, having adding a hydrochloric acid solution to it and creating a pH of 2.0 to 2.4, is divided into two parallel samples of the same volume, adding chloroform to each to obtain a chloroform to water ratio of 1:2.5, vigorously agitate, settle for 30 min before separation into three layers, and for water of the upper layer, carrying out the actions indicated in a), b), c), determining the silicon C₂ and C₂' mass concentrations, their arithmetic average C_2.1 and the silicon C₃ mass concentration, bound to organic-silicon compounds: C₃=C_1.1-C_2.1, and then determining the total concentration of silicon C₄: C₄=C_1.1+C_3.

EFFECT: reduction of analysis time to 1 hour and quantitative determination of the bound to humic substances silicon concentration.

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