Provision conditions for increasing the reliability of trace analysis of toxic metals

Abstract

Introduction. Heavy metals are included in one of the significant groups of ecotoxicants. Determining heavy metals at low levels is one of the main problems in analytical chemistry, which depends on various factors. Ignoring the contribution of these factors to the total uncertainty can increase the probability of distortion of the results due to an erroneous decision on the compliance of the obtained data with a particular standard. The most significant influences include the purity of reagents, dishes, and air in laboratory rooms. Purpose of the work. Search for ways of reducing the listed influences provided that the expense of time, material and labour resources are minimized. Materials and methods. In the course of the work, many experiments were carried out, including the analysis of nitric acid for the content of metals before and after cleaning by distillation, the analysis of washes from new fluoroplastic laboratory glassware and glassware that had been cleaned by steaming, an assessment of the effect of air pollution in the laboratory room based on a study of calibration curves, which were constructed at the analysis of standard iron solutions prepared in the Clean Workplace and in a conventional fume hood. All measurements were performed by inductively coupled plasma mass spectrometry on Agilent 7800 ICP-MS mass spectrometer. Results. The efficiency of the proposed methods for eliminating interfering influences on the analysis has been experimentally proved. Conclusion. The technical and analytical problem, which consists of finding optimal conditions for preparation of reagents, glassware cleaning and decreasing the influence of laboratory air pollution, allows to increase reliability of the obtained results and prevent distortion of information about the observed degree of environmental pollution.