Semi-automatic system for methylmercury determination in biological samples

For living creatures the presence of methylmercury is the most dangerous result of anthropogenic mercury emission. In order to improve and facilitate the determination of methylmercury (MeHg) with the manual Headspace Tenax Gas Chromatography-Atomic Fluorescence (HS-Tenax-GC-AFS) method, a low cost, semiautomatic measurement system (SA-GC-AFS) was designed and constructed. The developed MeHg determination method was optimized and validated according to the Eurachem recommendations. The validation parameters of the developed method were as follows: linearity: 0.9997, method detection limit: 1.4 ng/g; repeatability: 5.6%; recovery: 99-102%. The estimated combined uncertainty of the method was U=11.2%. Comparing with the manual method the repeatability was improved and the reduction of analyst effort was obtained. The SA-GC-AFS method was successfully applied to MeHg determination in 76 racoon (Procyon lotor) samples (muscle, liver, kidney, brain). The SA-GC-AFS system is the good, low cost alternative to the expensive commercial automated MeHg determination systems.