Simultaneous sub-picogram speciation of methylmercury and ethylmercury in caustic nuclear tank waste using direct aqueous propylation

Organomercury species are present at regulatory levels in the tanks at the Savannah River Site. Calibration of methylmercury and ethylmercury ranged three orders of magnitude, generating detection limits of 0.033 pg and 7.50 pg, respectively. Calibration verifications maintained 101 and 103% accuracy, respectively, with mean recovery from waste samples of 104%. Dilution volume was optimized to eliminate sample distillation, decreasing method runtime by 337% and reducing total instrumentation footprint by 60.4% compared with current standard methods. Compared with standard methods, this work represents a significant improvement in safety, efficiency, and reproducibility of organomercury speciation, particularly for industrial and nuclear analysis.