The methods were finally applied to several reference materials (DORM-1, DOLT-1 and TORT-1), achieving good accuracy.
In order to evaluate accuracy, certified reference materials (DORM-2 and DOLT-3) were analyzed after closed-vessel microwave extraction with tetramethylammonium hydroxide (TMAH).
To validate the accuracy of this method, certified reference materials DORM-2 (dogfish) and CRM No. 18 (human urine) were analyzed, and the determined values were in good agreement with the certified values.
Standard reference material DORM 2 (National Research Council of Canada: dogfish muscle) was used to check the accuracy and precision of analytical procedures.
The developed analytical procedure was validated with a certified reference material (DORM-2) and applied to the determination of organomercury incurred in waterfowl egg and fish samples.
Accuracy was checked and confirmed by analyzing certified reference material (DORM-2, dogfish muscle), and samples precision was satisfactory with RSD lower than 10%.
Quality control measurements for T-Hg included replicate analysis resulting in coefficients of variation < 10% and analysis of certified material (DORM-1, NRC, Canada).
Quality control measurements for total mercury included replicate analysis resulting in coefficients of variation <10% and analysis of certified material (DORM-1, NRC, Canada).
Quality control measurements for total Hg and Se included replicate analysis resulting in coefficients of variation < 10% and analysis of certified material (DORM-1, NRC Canada and CRM 278).
As a control, we used the National Institute of Standards and Technology dogfish muscle trace metal reference material (DORM-2) alongside the samples and our results were always within the total mercury certificate range (4.38 4.90 ppm).
A set of certified Material samples (DORM-2, National Research Council, Institute for National Measurement Standards, Ont; Canada) spiked with grade concentration of metals was analyzed to ensure the accuracy of metals.
