3. Results and discussions
3.1. Optimization of experimental factors for determination of gallium by
ICP OES
Preliminary studies were performed involving the nebulizers
(VGroove and seaspray) and also the hydrochloric and nitric acids.
Under the conditions established the results obtained demonstrated
that the combination of hydrochloric acid and the nebulizer seaspray
allows the determination of gallium with higher sensitivity. So, some
experimental parameters were optimized using multivariate techniques
for determination of gallium employing this nebulizer in the
presence of hydrochloric acid. Firstly, a full two-level factorial design
was performed involving the factors: RF power, hydrochloric acid
concentration and nebulizer gas flow rate. Triplicate of the central
point were performed in order to determine the experimental error
and evaluation of the curvature. The experimental dominions (as
coded and real values) for each factor and the chemometric response
Table 1 (emission intensity at 294.363 nm) are shown in Table 3.