Experimental design approach for the extraction of methylmercury from certified reference materials using microwave energy

Methylmercury (MeHg) has been extracted from biological samples using Microwave Assisted Extraction (MAE). In order to find the optimal experimental conditions to extract samples a screening experimental design was used allowing the establishment of the significant MAE operating variables affecting the total recovery of Methylmercury. A reference material (DORM-1) was used as sample in this screening study. Four variables were selected for evaluation: temperature, extraction time, added 6M HCl amount and solvent (toluene) volume. The statistical treatment of the obtained results indicated that HCl amount and temperature were the only variables that significantly affect methylmercury recoveries. Then, to obtain the optimal conditions a response surface experimental design was applied and a reproducibility study was carried out in the optimum reached conditions showing a mean recovery of 100.2±2.0 % in the case of DORM-1. Other available reference materials were also applied to validate the microwave extraction procedure.