The matrix effect was evaluated using the analyte addition
technique to choose the calibration technique for this method.
Cadmium solutions with final concentrations in the range of
0–500 ng L1 were added to vinegar samples, and the cadmium
concentration of each sample was determined with the direct
method proposed herein. In this experiment, the equation of the
analytical curve (expressed at the 95% confidence level) was as
follows: