Analysis of HgT in Sediments, Soils and Plants Brooks-Rand MERX

Analysis of Total Mercury in Sediments, Soils, and Plants by Cold Vapor Atomic Fluorescence Detection with the Brooks-Rand “MERX” Automated Mercury Analytical System.

The following standard operating procedure (SOP) is used by the U.S. Geological Survey’s Mercury Research Laboratory (MRL) to determine total mercury (HgT) concentrations in sediments, soils, and plants. This SOP describes the preparation of the sample and subsequent analysis. Lyophilized and homogenized solid sample is weighed into Teflon bombs. The sample is first digested in concentrated aqua regia and then diluted up to 30 ml with a solution of 5% Bromine Monochloride (BrCl). Immediately prior to analysis, the BrCl is neutralized by the addition of Hydroxylamine Hydrochloride (NH2OH*HCl). Following neutralization, Stannous Chloride (SnCl2) is added to the sample to reduce the mercury from Hg2+ to Hg0 . The volatile Hg0 is purged from the sample and captured on a gold sand trap, desorbed, and detected by cold vapor atomic fluorescence spectrometry (CVAFS). Sample analysis is conducted by the Brooks-Rand “MERX” automated mercury analytical system. Quality assurance and control protocols are employed throughout sample preparation and analysis, including: laboratory practices to prevent sample contamination, method and analytical blanks, method and analytical replication, analytical matrix spikes, and analysis of certified reference material (CRM).

Mercury Research Laboratory, 2016