Especiação de arsênio em água e tecido de peixe empregando extração em fase sólida (SPE) e espectrometria de emissão óptica com plasma acoplado indutivamente (ICP OES)

Abstract

The adverse effects caused by potentially toxic elements on the environment and human health vary according to the elements’ species, which differ in terms of toxicity. Arsenic (As) exposure is a global public health problem, which has led to an increased demand for As speciation analysis. The goal of this research was to develop a method for As speciation in water and fish samples considering As(III), As(V), DMA, and MMA species to be included in the scope of the Venturo Análises Ambientais laboratory. For this, Solid Phase Extraction (SPE) was coupled with Inductively Coupled Plasma Optical Emission spectroscopy (ICP-OES) detection. The method developed was based on two sequential extractions, one using a cation exchange cartridge (SCX) and the other an anion exchange (SAX) cartridge. DMA was retained on the SCX cartridge and eluted with 1 mol l-1 nitric acid. As(III) was not retained on the cartridges and was collected at the end of the extraction. As(V) and MMA were retained on the SAX cartridge, MMA was eluted with 1 mol l-1 acetic acid, and As(V) was quantified by calculation. After testing the selective detection of As species using four cartridges manufactured in Brazil, Purifica SCX and Purifica SAX were selected since they showed satisfactory retention percentages. The method for fish tissue samples was based on extraction with polar solvents, sonication, and centrifugation and was effective in recovering As species. In this procedure, an aqueous extract was obtained and submitted to the same separation process proposed for water samples. The methods were validated, and the Venturo Análises Ambientais can request to INMETRO the inclusion of As speciation considering As(III), As(V), DMA, and MMA in the laboratory scope. The quantification limit to be reported is 0.050 mg l-1 for water and 0,500 mg kg-1 for fish tissue samples.