Method validation for determination of trace elements in urine for occupational evaluation of foundry workers

Abstract

The trace elements are classified as essential and non-essential. The essential are necessary for the functioning of the organism. Nonessentials, besides being unnecessary, are potentially toxic. Occupational exposure to these elements can cause numerous injuries to workers, and this risk makes it necessary to develop techniques for monitoring their concentrations in biological samples. Inductively coupled plasma mass spectrometry (ICP-MS) is an analytical technique of high sensitivity, precision and reliability that allows rapid and multi-element analysis and is ideal for the analysis of metals in clinical samples. There are several studies of the application of ICP-MS in blood, plasma and urine analysis. Urine, according to NR 7, is the most appropriate biological fluid for the analysis of Arsenic, Cadmium, Lead, Chromium and Mercury. There are studies of the application of ICP-MS for determination of other metals in urine, such as Iron, Copper, Zinc, Selenium, Calcium, Magnesium, Aluminum, Barium, Beryllium, Cobalt, Cesium, Manganese, Nickel, Platinum, Antimony, Tin , Tellurium and Uranium. In these studies, the samples are treated with simple dilution and direct injection in ICP-MS. The objective of this project is the development, validation and application of a method for determination of trace elements in workers' urine via ICP-MS. With this, it is possible to investigate a possible relationship between the concentration of metals in workers' urine and occupational exposure, as well as to determine possible sources of contamination and deficiencies of essential elements. For the development of the method, the following parameters will be evaluated: sample dilution, optimization of ICP-MS variables, evaluation of the use of internal standards and evaluation of calibration in aqueous medium or by matrix adjustment. The method developed will be validated through the study of linearity, limits of detection and quantification, repeatability, reproducibility, precision and accuracy. Workers from the foundry industry of ferrous and non-ferrous metals will participate in the study. They should collect urine in metal-free vials in the morning, and store it under refrigeration. The collected urine will be diluted in acid medium and analyzed by ICP-MS.