3. Results and discussion
3.1. Comparison of optical temperature control and current
temperature control
When the concentrations of Cd standard solutions were
changed, the absorbances were measured by optical temperature
control and current temperature control respectively under
the same instrumental conditions. The results were shown in
Table 2. It indicated that absorbance and precision of optical
temperature control were higher than those of current temperature
control obviously. The sensitivity of optical temperature
control increased by 60–100% in the range of 1∼40 ngmL−1
Cd. The background absorbance was greatly reduced by optical
temperature control.
3.2. GFAAS program optimization
The furnace program was finalized after optimization of drying,
ashing, and atomization temperatures for aqueous standards.
The ashing temperature studies were conducted at temperature
ranging from 300 ◦C to 500◦C. The analyte loss was observed
at temperatures above 500 ◦C. The ashing time curve was carried
out. The results showed the absorbance was maximum by
keeping the ashing time for 25 s. Similarly, atomization temperatures
were investigated from 1100 ◦C to 1800 ◦C. The minimum
temperature required to atomize the analyte was 1400 ◦C. The
optimum atomization time was 6 s. It was found that these operating
conditions were appropriate for the paint matrices and were
used for the rest of this investigation. The ashing temperature
and atomization temperature for this study were kept at the minimums
of 400 ◦C and 1400 ◦C to prolong the tube life. Each