SU812719A1 - Method of chemiluminescent lead determination - Google Patents

Description

(64-) METHOD FOR CHEMILUMINESCENT LEAD DETERMINATION

The invention relates to analytical chemistry and can be used in the analysis of air, water, high-purity materials, biological objects. Luminescent methods for the determination of lead are known, based on the measurement of the luminescence spike upon the excitation of frozen to -196 C lead chloride complexes, the detection limit of Pb in 0.2 ml of solution flj. However, this method is not widely available for mass use in chemical laboratories because of the complex apparatus and the need to work at very low temperatures. The closest to the invention to the technical essence and the achieved result is the method of chemiluminescent determination of lead, including the processing of the analyzed sample with an organic reagent in the presence of hydrogen peroxide. Luceginin 2 is used as an organic reagent. However, the known method allows to determine only 0.2 µg of lead in 1 Gl. In addition, it requires a significant investment of time due to phototographic registration of the amount of luminescence. The purpose of the invention is to increase the sensitivity of the analysis. This goal is achieved by the method of chemiluminescent determination of lead, which includes treating the sample being analyzed with an organic reagent in the presence of hydrogen peroxide. A distinctive feature of the process is the use of 4-amino, phthalhydrazide as an organic reagent. The optimal conditions for the reaction of the interaction of lead with 4-aminophthalhydrazide (4-APG are 4-APG concentration of 3 to 10 g-mol / l hydrogen peroxide 5-10 g-mol / l and a pH of 12.3 Examples enter the cuvette 0, 5 ml of 5-10 HgO solution, from 0.05 to 0.5 ml of 10 M solution of lfg (NOs) o, bidistilled and a mixture containing 0.5 ml of 4-APG solution and 1 ml of 0.18 M KOH solution The total volume of the solution in the wipe is 5 ml. The chemiluminescence is measured using a photomultiplier, registering the maximum intensity of the luminescence (after 1 min from the start of the reaction or the amount of luminescence in 2.5 minutes). g; vintz are found on an appropriate calibration chart. V. Table 1 shows the results of determining lead in one solution.

Only cobalt ions (//) interfere with the determination of lead (in comparable and large quantities, giving a bright flash. Copper (Ttj, iron (III) and bismuth tloes) (luminescence is slightly diminished in comparable quantities), but in the presence of trilon they completely masked and do not interfere with lead determination.

Example 2. Determination of lead in the air. The filter, through which the air analyzed for lead is passed, is crushed, poured into a test tube, filled with 2.5 ml of a mixture of NLOS and HgOg and vigorously shaken for several minutes. UFO concentration: in a mixture of 0.9 I, HgOg 0.02 I. The resulting solution is diluted 10 times, filtered if necessary, and lead is determined in aliquots using the proposed method.

The described method of transferring lead from the filter to the solution has

advantages over the currently used one in that it eliminates the operation of burning, ashing and calcining the residue, which reduces the analysis time from

12-14 h to 20-30 min.

-3

0.5 ml of Z.-10M K-APG solution, 2 ml of buffer solution fHgBO-KOH, pH 12.5), 0.5 MP of 510 M KOH solution (for neutralization) and the mixture consisting of 0.5 ml of 5-10 M solution and 1 ml of the test solution, the total volume of the solution in the cuvette is 5 ml. In the resulting solution, the luminescence is measured / described in Example 1).

To build the calibration graph, a clean filter is used which is carried out through all the operations. As a standard, use a solution of P CA / OJ) (from 0.1 to 0.4 ml). The results of the analysis of one sample are given in table. 2

The proposed method allows to determine 2 needle lead in 1 ml of solution,

In addition, it allows to increase the accuracy of analyzes by significantly reducing the time costs.

Table

Table 2

Claims (1)

Claim A method for the chemiluminescent determination of lead, comprising treating an analyzed sample with an organic reagent in the presence of hydrogen peroxide, characterized in that, in order to increase the sensitivity of the analysis, 4-aminophthalhydrazide is used as an organic reagent.