FIELD: chemistry.
SUBSTANCE: sample is taken while drawing through an atmospheric air filter. The filter is then decomposed by the sample preparation method in a muffle furnace. A solution of the internal standard is added to the filter, placed in the muffle furnace and held in series at a temperature of 100°C for 40-60 minutes, at a temperature of 250°C for 40-60 minutes and then the ashing is carried out at a temperature of 450-500°C. The ash is wetted with concentrated nitric acid, heated on a sand bath and evaporated to a wet salt state. After cooling, they are dissolved in 5 cm3 of 1% aqueous solution of nitric acid, transferred to a volumetric tube and the resulting volume is adjusted to 10 cm3 by 1% aqueous solution of nitric acid. The sample is placed in the tube of a sampling device of a mass spectrometer with an inductively coupled argon plasma and measurement is carried out using a reaction-collision cell with helium passing through it as a reactant gas, and the concentration of a particular metal is determined using a calibration chart, taking into account the adjustment of the air volume sampled for analysis to normal conditions. In this case, the sample is taken by drawing the test air in a volume of 6-20 m3. Before adding the inner standard solution to the filter, 0.1 cm3 of ethyl alcohol and 0.5 cm3 of 20% solution of ammonium sulfate or potassium disulfate in deionized water are successively injected into a quartz cup. 0.1 cm3 of the internal standard solution injected afterwards contains a mass concentration of the reference element - indium - in an amount of 100 mcg/dm3. Moreover, the ashing in the muffle furnace at a temperature of 450-500°C is carried for 3.0-3.5 hours, and the ashes formed by ashing are wetted with 0.3-0.5 cm3 of concentrated nitric acid with density of 1.415 g/cm3. Measurements in the prepared sample of specific metal content in a mass spectrometer are carried out by passing helium through a reaction-collision cell at a rate of 5.2-5.5 cm3/min. It is possible to determine 15 chemical elements - metals - in atmospheric air from a single sample in a wide range of concentrations at a level from 0.000001 to 5 mg/m3.
EFFECT: expanded ability to determine elements.
5 cl, 9 tbl
Authors
Dates
2017-08-14—Published
2016-10-10—Filed