Arsenic quantification techniques and ISO/IEC 17025 accreditation in Brazil

Abstract

The importance of arsenic (As) quantification in environmental compartments is due to its risks to ecosystems and public health. There are reports of high concentrations of this metalloid in Brazil and technological differences between states are observed. The objective of this work was to present and discuss current scenarios of accreditation and compare the limit of quantification (LOQ) of As by analytical technique in Brazil. Data from accredited laboratories were collected on Inmetro website and in state metrological networks and then grouped and analyzed by state, matrix and analytical technique. There are large discrepancies between the number of laboratories per state and a good correlation with gross domestic product (GDP). Almost all laboratories have a LOQ less than the environmental limits. The observed list of techniques sorted from lowest to highest LOQ values is: for liquid samples ICP MS (inductively coupled plasma mass spectrometry), ET AAS (electrothermal atomic absorption spectrometry), HG AAS (hydride generation combined with atomic absorption spectrometry) or HG ICP OES (hydride generation combined with inductively coupled plasma optical emission spectrometry) and UV VIS (visible ultraviolet spectroscopy); for solids samples HG ICP OES, ICP MS, HG AAS, ET AAS and FAAS (flame atomic absorption spectrometry); and for bioindicators ICP MS, HG ICP OES. Analysis of As species is accredited in only one laboratory, but does not include all species.