3. Results and discussion
The validity and accuracy of the methodology was checked with certified reference material, DORM-2 which had certified value 4.64 ± 0.260 lg/kg of Hg and the experiment values at 95% confidence interval (n = 6) was 4.61 ± 0.211 lg/kg obtained as shown in Table 1. The linear range of the calibration curve reached from the detection limit up to 25 lg/l for Hg The linear regression equation and the coefficients of correlation for Hg, under the selected analytical conditions measurements, were y = 1.8
1.1
* 10
3
, where y is integrated absorbance and x is the concentration in each case expressed as lg/L and r = 0.9948. The precision for six replicate determinations was 4.6%. The detection limit and quantitation of Hg were calculated as LOD ¼ 3 s=m and LOQ ¼ 10 s=m. where s is the standard deviation of 10 measurements of reagent blanks and m is the slope of the calibration curve in the best experimental conditions. The calculated LOD was 0.117 lg/kg and LOQ was 0.382 lg/kg, which were quite low and adequate to determine Hg at trace levels in understudied samples.
* 10
3