The FAAS analytical signal increased proportionally with
increasing preconcentration time, which means that retention
efficiency was constant. The experimental preconcentration
factor, calculated as the ratio of the slopes of the calibration
graphs obtained with and without preconcentration, was
evaluated as 15.7. Sample volumes greater than 3.4 ml can be
used and thus higher preconcentration factors can be achieved;
for a sample volume of 10 ml, a preconcentration factor of 47
was achieved. As the sample volume used in the method was 3.4
ml and the injected eluent volume was 213 ml, the theoretical
preconcentration factor should be 16, which demonstrates the
good performance and the minimum dispersion of the FI
system.