In Fig. 3a, the signals obtained for standard solutions of 0.5–50 μg/mL Cr are shown. The applied sample volume was 30 μL using micro-injection of the discrete samples. From these data, a 0.0089 μg/mL limit of detection (LOD) and a linear detection range of 0.2–50 μg/mL could be concluded. Fig. 3b shows the signals of a number of 30 μL samples containing 4 μg/mL Cr as an example of the