Two open wet oxidation methods are described for the digestion of selected seafoods prior
to total mercury determination using a cold vapour atomic absorption spectrophotometric
technique. The first employs two acids (i.e. HNO3 and H2SO4) and two oxidants (i.e.
KMnO4 and K2S2O8), and is suitable for use with a Perkin-Elmer Mercury Analysis System
(MAS) and a Perkin-Elmer Mercury Analyzer 50A (MA). Excellent recoveries were
obtained for mussel samples spiked with various quantities of inorganic mercury
[Hg(N03)2]. For the optimum part of the calibration curve of the MAS (0.1–0.7 μg/ml Hg),
the percentage recovery (%R) fluctuated between 98.26 and 101.98. The limit of detection
(LOD) was calculated to be 18.7 ng of mercury per sample analysed and sensitivity of 0.011
μg of mercury was obtained. Results for fish samples determined with both units showed
excellent agreement and precision (RSD = 3.23 -4.25). However, the MA was found
inadequate for the determination of the low mercury levels encountered with the mussel
samples. It was shown that a desiccant assembly must be installed whenever samples with
low mercury content are analysed, i.e. less than 0.5 μg per sample digested. [Continues.]
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.