Evaluation of Greenness of Methods for the Determination of Mercury in Mushrooms

In the present study, two analytical methodologies, one based on direct thermal degradation of samples followed by atomic absorption analysis (TDA-AAS), and another one, which consists on acid microwave-assisted digestion (MAD) followed by cold vapour atomic fluorescence determination (CV-AFS), have been applied to determine mercury in mushrooms. Both methodologies found the same concentration values, from 258 to 570 ng g-1 (dry weight), for nine samples. Analysis based on thermal degradation provided a limit of detection of 3 ng g-1 similar to that found by CV-AFS, and a relative standard deviation of 3 %, three times higher than that of CV-AFS. However, the direct analysis of untreated samples agrees well with green analytical principles because it involves less reagents consume and reduces waste generation. In fact, at analytical Eco-Scale, TDA-AAS procedure involves a green score of 92 points in front of the 59 points obtained for CV-AFS method.