3.5. Sensibility and detection limit
A reasonably good accuracy and precision of measurement is
a prerequisite of any analytical techniques. Therefore, the sensibility
and the detection limit were regularly studied. In this
determination, the sensibility (calculated as the characteristic
mass and based on the integrated absorbance of 0.0044) of cadmium
was 3.0 pg. And the average detection limit (calculated
on 3σ/slope of the calibration curve, where σ is the standard
deviation of 10 consecutive measurements of the reagent
blank solutions performed under the general procedure) was
9.6 ng L−1.
3.6. Application
3.6.1. Analytical results for cadmium in paint samples and
precision
The developed method was applied to the Cd determination
in five paint samples in the presence of 2.50gmL−1 lanthanum
modifier with six parallels performed. The experiment analytical
results are described in Table 4. The content of dissolved
cadmium in paint sample was determined by extraction method,
while total content of cadmium in paint sample was obtained by
dry digestion method. The relative standard deviations (R.S.D.)
for six replicate measurements of each sample were reasonable,
all being below 2.5%, which suggested that the precision of analytical
technique was excellent and this method had effective
reproducibility.