SU1659801A1 - Method of photometric determination of lead in bronze - Google Patents

Abstract

This invention relates to analytical chemistry, in particular to photometric methods for the determination of lead in bronze. The purpose of the invention is to improve the accuracy of determining lead in bronze to 0.01%. For this purpose, the analyzed sample is dissolved in an inorganic acid, and lead is separated from the solution using an ion exchange resin, for example, the EDE-10P or AN2FN brand. wash out of the resin with water, alkalize the aqueous solution to pH 10 and add a 0.025% sulfarsazen solution in a 0.05M borax solution to the neV, and absorbance of the obtained colored solution is measured at a wavelength of 500 nm

Description

This invention relates to analytical chemistry, in particular to photometric methods for the determination of lead in bronze.

The aim of the invention is to increase the accuracy of determination of lead to 0.01% in bronze.

The method is carried out as follows.

The sample to be analyzed is dissolved in an inorganic acid, lead is separated from the solution using an ion exchange resin, washed out of the resin with water, an aqueous solution, alkalized to pH 10, 0.025% sulpharsacene solution in a 0.05 M solution of borax is added and measured. at a wavelength of 500 nm, the optical density of the obtained colored solution, by which the lead concentration in the sample is judged.

Example. Two sample of 1.0 g of bronze A9Zh4 brand is placed in a conical flask

with a capacity of 250 ml. Dissolve in 15 ml of nitric acid (1: 1). Evaporate to dryness. Pour 100 ml of 2 n. hydrochloric acid. Heat to dissolve the salts and then cool.

The mixture is passed through a column with charged resin in the SG form (100 ml of 2N HCI are preliminarily passed at a rate of 1.5 - 2.5 ml / min) of the EDE-10P or AN2FN brands at the same rate. Washed with 150 ml of 2N HCI. Wash out zinc 100 ml of O.Zn. HCI. Lead is then washed with 80 ml of water into a volumetric flask with a bone volume of 100 ml. Make up to the mark with water and mix. A 50 ml aliquot is taken in a 100 ml volumetric flask. Neutralized with ammonia buffer (pH 10) until the red color of the paper congo and add an additional 0.5 ml of buffer. 5 ml of a 0.05 M solution of sulfarsazen in a 0.05 M solution of borax are poured. Add water to the mark and mix. After 30 min, the photocolorimeter is used against the background of the blank sample in cuvettes.

e

 SP Yu 00

about

2 cm thick with a green light filter (length, waves 500 mn). Through the entire course of the analysis, the blank sample and the reference alloy are conducted.

To determine the amount of lead, use the following relationship.

RV,% °

Dx

at

where Pb is the amount of lead contained in the alloy under study,%;

c is the amount of wine contained in the standard,%;

Oet is the optical density of the standard;

Ox is the optical density of the alloy under study.

The linearity of the calibration curve of the dependence of optical density on the lead content in the alloy is observed in the range of 0.003 - 0.02%.

Claims (1)

The invention of the method of photometric determination lead in a bronze sample, including dissolving the sample to be analyzed in an inorganic acid, adding a color reagent, and measuring the optical density of the resulting colored solution, which is used to judge the lead concentration in the sample, characterized in that, to improve the accuracy of determination, lead is extracted from the sample solution using an ion-exchange resin, it is washed out of the resin with water, the resulting lead solution is alkalinized to a pH of 10; a 0.025% solution of sulfarsase is added to it as a color reagent: ical density of the colored solution was measured at a wavelength of 500 nm.