Routine, Reliable Mercury Screening

Salmon and sardine samples were spiked with 10 ppb mercury prior to digestion and compared with unspiked samples to calculate recoveries. These 10 ppb spikes would correspond to a concentration of 2 mg/kg in normal fish samples assuming a sample weight of 0.5 g and demonstrate the accuracy of the analysis at levels appropriate to current legislation. The agreement with expected results was excellent, with the recovered values all falling within 6% of the expected values. This demonstrated the repeatability and accuracy of both the sample digestion procedure and the vapor analysis using AA spectrometry.

To ensure the accuracy of sample preparation, digestion, and analysis, three separate samples of the DORM-2 standard reference material were also examined. The recoveries from these samples were excellent, with an accuracy of ±2% or better.

AA spectrometry coupled with a VP100 vapor generation accessory is the most comprehensive technology available for the analysis of trace levels of mercury in fish, combining speed, excellent linear range, stability, and accuracy. Analyzing samples in only 90 seconds, the method meets the high throughput requirements of laboratories while also offering superior sensitivity, full traceability and ease-of-use.

Dickson is an applications chemist at Thermo Fisher Scientific. For more information, reach her at hazel.dickson@ thermofisher.com or +44 (0) 1223 347 400.

References

1. Environmental Protection Agency, Mercury, Basic Information, www.epa.gov/mercury/ about.htm.
2. Environmental Protection Agency, Mercury, Health Effects, www.epa.gov/mercury/effects.htm.
3. Food And Drug Administration, Industry Activities Staff Booklet, August 2000, Action Levels for Poisonous or Deleterious Substances in Human Food and Animal Feed, www.cfsan.fda.gov/~lrd/fdaact.html#merc.
4. Public Affairs Television, Science and Health, The Mercury Story, www.pbs.org/now/science/mercuryinfish.html.
5. US Environmental Protection Agency, Air and Radiation, Clean Air Rules of 2004, Clean Air Mercury Rule, www.epa.gov/camr/.