An instrumental correction for the determination of mercury in biological and sediment samples using cold vapor atomic absorption spectrophotometry

Low recovery rate and inconsistent measurements were found in the determina tion of mercury by method of cold vapor atomic absorption spectrophotometry using the hydride formation system (Hitachi HFS-2, Hitachi Ltd., Tokyo). T o overcome this problem of insufficient reaction time we developed a simple T-joint device attaching to the commercial HFS-2 system for the determinat ion of mercury in various biological tissues and sediment samples. The T-jo int device was designed to combine sample and reductant injection which inc reased the reaction time of the sample allowing a complete formation of mer cury vapor and speeding up the analysis process in comparison to the tradit ional cold vapor atomic absorption spectrometric method. Recoveries of merc ury were in the range 95% - 100%. The corrected procedure gave precise and accurate readings with several certified reference materials: NIES No.2 fro m the Japan Environment Agency; IAEA-356 from the International Atomic Ener gy Association, and DOLT-2, DORM-2, TORT-2, PACS-1 and MESS-2 from the Nati onal Research Council of Canada. Simple acid digestion methods were develop ed based on the sample Hg level and the nature of the sample. The sample de tection limits were 0.0125 mug g(-1) fresh weight and 0.0625 mug g(-1) dry weight for biological samples, and as low as 0.0125 mug g(-1) dry weight fo r sediment samples. These analytical protocols we established met the gener al requirements in environmental research and monitoring of mercury polluti on.