METHOD OF PREPARING SAMPLES FOR DETERMINING CONTENT OF HEAVY METALS IN SUSPENDED SUBSTANCES OF NATURAL WATER BY ATOMIC ABSORPTION METHOD

摘要

FIELD: physics.;SUBSTANCE: disclosed is a method of preparing samples for determining content of heavy metals in suspended substances of natural water by atomic absorption method, including filtering natural water, adding to the polymer filter with precipitate of suspensions two acid reagents, one of which is nitric acid, heating the solid phase of the sample with the reactants until acid-soluble forms of metals are extracted from it, adding deionised water, dissolving acid-soluble metal forms therein, and using the obtained mineralase for subsequent atomic absorption measurement of mass concentration of heavy metals. Hydrogen peroxide is used as the second acid reagent; addition of reactants to the filter with sediment suspension is performed in the following sequence and ratio: nitric acid (40±2) %, hydrogen peroxide (20±1) %, deionised water up to 100 %, and heating of solid phase of sample with reagents and dissolution of extracted acid-soluble forms of metals in deionised water is carried out simultaneously in closed vessels under the effect of microwave radiation power of 300 to 1,050 W in two stages to maximum temperature of 200 °C for 70–75 minutes, including cooling.;EFFECT: faster preparation of samples, accuracy of analysis, as well as improved ecology in laboratory conditions.;1 cl, 3 tbl, 2 ex