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Brooks Applied Labs currently offers mercury (Hg) stable isotope ratio testing for environmental forensic studies. Mercury has a unique isotopic pattern and small differences in the ratios of these isotopes can help in identification of the source, transport, and biogeochemical fate of mercury in atmospheric bulk deposition, soils, freshwater, and seawater matrices.

Typically, accurate stable metal isotope measurement is achieved by thermal ionization mass spectrometry which can only be found in academic research environments. Brooks Applied Labs utilizes an Inductively Coupled Plasma Mass Spectrometer equipped with a Dynamic Reaction Cell (DRC) to achieve similar results with appropriate QA/QC. This specific instrument allows extremely accurate and precise determination of isotopic ratios limited with counting statistics (< 0.1% most ratios). Monitoring of possible interfering elements, such as tungsten (as WO) is also possible to ensure the isotopic pattern is interference free. The DRC technology facilitates collisional damping of the ion beam fluctuations, which greatly reduces the internal variability and increases precision. The confidence in isotopic ratio testing is also typically limited by sample concentration and matrix interferences. By identifying these interferences and implementation of preconcentration techniques, utilization of cold vapor reaction techniques, and appropriate sample preparation methods, the applicability of mercury isotopic ratio testing for most matrices is now a reality. In addition, institution of proper sampling plans is a necessity to ensure all localized variables are identified to account for as many variables as possible.

Use of mercury stable isotope ratio testing can often decrease the scope of work for investigative projects, ultimately reducing the cost of the investigation and increasing the confidence in results due to the absolute nature of the testing procedure. This is especially important when dealing with tort and environmental forensic litigation cases.

For project inquiries, applicability of methodologies, and pricing information feel free to contact us.

Actual QC Data for NIST 1631d

198Hg/202Hg

199Hg/202Hg

200Hg/202Hg

201Hg/202Hg

Published Ratios

0.33647

0.568345

0.776861

0.442772

Measured Ratios

0.3363

0.56838

0.7769

0.44279

Average internal precision (% RSD)

0.10244

0.07268

0.06028

0.07683

External precision (% RSD)

0.01545

0.01496

0.02910

0.06361