Sample preparation

Tube furnace combustion lines

We are currently using 4 parallel double stage tube furnace lines to decompose and pre-concentrate Hg from a variety of solid samples. Our methods are inspired from the original Biswas et al. (2008) combustion method for coal. We exclusively use oxygen as combustion gas. Samples (0.1 to 10 grams) are weighed into quartz tubes sealed with quartz wool and inserted into the first oven, which is then ramped from room T to 1000oC over 5-6 hrs. The second oven is consistently held at 1000oC in order to fully decompose combustion products. Gaseous Hg liberated from the sample is pre-concentrated at the oven-exit using a commercial Savillex impingers, filled with 30 mL’s of 40vol% inverse aqua regia (2:1 HNO3:HCl). After combustion samples, are diluted to 20vol% inverse aqua regia with DI water and stored in a fridge. Extraction yields are checked by AFS before direct analysis of the 20vol% inverse aqua regia solution by cold vapor generation MC-ICP-MS.

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