SU1394101A1 - Method of determining bromides - Google Patents

Abstract

The invention relates to analytical chemistry, namely to methods for determining bromides, and can be used to increase the sensitivity, selectivity and expressivity of the method. 1 ml of the analyzed solution is introduced into the aeration vessel containing 7 ml of the oxidizing solution. The composition of the solution is 0.13 mol / l bichroma potassium in 8.5 mol / l sulfuric acid. The oxidizing solution with the sample is purged with nitrogen, which passes through two industrial flasks filled with 4 M NaOH and 0.1 M in O, 7 M solutions. The purge rate is 1.5 l / min. The bromine emitted during the oxidation of bromides with a stream of inert gas through a glass tube is fed through a glass bubbler into a cell of a chemiluminescent photometer filled with an alkaline solution of luminol. The maximum chemiluminescence signal is measured and the bromide content in the sample is determined from the calibration curve. The method allows to determine up to 2.0 jtr of bromides within 1.5-12 minutes. 1 tab. (L

Description

The invention relates to analytical chemistry, in particular to methods for the distribution of bromides, and can be 1: resolved for their determination in sea, river, mineral rain and drinking water.

The purpose of the invention is to increase the sensitivity, selectivity and ex-pressure of the analysis.

Example 1.1 ml of the assay solution is introduced into an aeration vessel containing 7 ml of an oxidizing solution. Composition of solution), 13 mol / l potassium dichromate in 3.5 mol / l sulfuric acid. The oxidizing solution with the sample is purged with nitrogen, which passes through two industrial flasks filled with 4 M NaOH and 0.1 M in 0.7 M solutions. The purge rate is 1.5 l / min. The bromine implanted during the oxidation of bromide with an inert gas flow through the glass tube is fed through a glass sparger in a cell of a chemiluminescent photometer filled with an alkaline solution of luminol. The maximum chemiluminescence signal is measured and the bromide content in the sample is determined from the graduation curve.

The table presents the experimental results of the dependence of the sensitivity of the determination of bromides on the concentration of chromic and sulfuric acids in the oxidizing solution and the rate of purging with an inert gas.

As follows from the resultsj presented in the table, the best sensitivity of the assay, which provides for the determination of 2.0 Ng / ml of bromides, was obtained at the concentration of bichromate

potassium 0.1-0.15 mol / l and sulfuric acid 7.4-9.2 mol / l in the oxidizing mixture and the rate of purging it with an inert gas of 1.3-1.7 l / min. An increase in the concentration of potassium bichromate and sulfuric acid in the oxidizing solution is impossible, since at these concentrations a saturated solution forms and the potassium bichromate precipitates.

The method of determining bromides will lower the detection limit by 126 times. The analysis time is reduced 60 times. Bromide is determined in the presence of a 10-fold amount of iodide and a 10-fold amount of chloride.

Claims (1)

Invention Formula A method for determining bromides by oxidizing to bromine with a chromium mixture, separating bromine, reacting it with an alkaline solution of luminol and measuring the intensity of chemiluminescence, characterized in that, in order to increase the sensitivity, selectivity and expressivity of the analysis, the oxidation of bromides leads to O, 10-0.15 M potassium bichromate in 7.4- 9.2 M sulfuric acid, and the release of bromine is carried out by flushing the oxidizing solution with a stream of inert gas at a rate of 1.3-1.7 l / min and using a gas flow into the cell of a chemiluminescent photometer. 8.5 8.5 8.5 8.5 5.0 2.0 2.0 2.0  Table continuation