GREENNESS AND WHITENESS PROFILES OF UV/VIS PHOTOCHEMICAL VAPOR GENERATION CAPACITIVELY COUPLED PLASMA MICROTORCH OPTICAL EMISSION SPECTROMETRY METHOD FOR MERCURY DETERMINATION AND SPECIATION IN FOOD AND WATER

Abstract

The aim of the study was the evaluation of greenness and whiteness profiles of UV/Vis photo-induced cold vapor generation (UV/Vis-PVG) capacitively coupled plasma microtorch optical emission spectrometry methods for Hg determination and speciation as CH₃Hg⁺ and Hg²⁺. Sample preparation for CH₃Hg⁺ determination in fish tissue consisted of an extraction in HBr–toluene–aqueous L-cysteine solution and UV-PVG in 0.6 mol L^-1 HCOOH. Total Hg was determined in food samples following ultrasound assisted extraction in concentrated HCOOH and UV-PVG. Hg speciation was based on extraction in HCOOH and UV/Vis selective derivatization of total Hg/Hg²⁺. The greenness profile was assessed by National Environmental Methods Index, Analytical Eco-Scale, Green Analytical Procedure Index and Analytical Greenness Metric, while the whiteness profile was evaluated using the Red–Green–Blue (RGB) 12 algorithm. The methods, based on miniaturized instrumentation, were characterized by a higher greenness and whiteness compared to the traditional SnCl₂ cold vapor generation inductively coupled plasma optical emission spectrometry, SnCl₂ cold vapor generation atomic fluorescence spectrometry, and sometimes than that of thermal decomposition atomic absorption spectrometry. This study is a novelty because, to the best of our knowledge, is the first approach of this kind for Hg determination and speciation based on optical emission spectrometry using a fully miniaturized instrumentation.