2005 年 51 巻 2 号 p. 220-223
Total mercury level in biological samples have often been analyzed using atomic absorption spectroscopy (AAS), following the conversion of all the mercury to atomic mercury vapor. On the other hand, analysis of methylmercury (MeHg) using an electron capture detector-gas chromatography (ECD-GC) has well been established. For ECD-GC analysis, the MeHg in samples must be extracted in toluene as its complex with chloride or dithizone. Here, we attempted to analyze MeHg content in rat tissues by the oxygen combustion-gold amalgamation method using AAS, following toluene extraction and back extraction to an aqueous medium. Since all the processes were carried out in a microtube using a micro homogenizing system, microtube mixer and a micro centrifuge, the time required to prepare 12 samples was as short as 30 min. Recoveries of MeHg added to rat brain, kidney and liver homogenates were 83.6-86.7%. Accordingly, a recovery factor of 0.85 was necessary to calculate MeHg content from the analytically obtained value. Using the present method and the previously established method for inorganic mercury quantification, the sum of methyl and inorganic mercury contents in MeHg-treated and non-treated control rat tissues fitted well the total mercury contents. The present method would be useful to estimate, at least roughly, MeHg content in biological samples using the same instrument as total mercury analysis.
