Time measurement-visual analysis of nickel(II) using autocatalytic reaction with sodium sulfite/hydrogen peroxide system and its application to the length detection-flow analysis

Trace amounts of nickel(II) can function as a trigger (=reaction initiator) in an autocatalytic reaction with the sodium sulfite/hydrogen peroxide system. Based on this finding, sub-μg L−1 levels of nickel(II) were determined by a time measurement using the autocatalytic reaction. The detection range using the above method was 10−9–10−5 M, the detection limit (3σ) was 8.1 × 10−10 M (0.047 μg L−1), and the relative standard deviation was 2.66% at nickel(II) concentration of 10−7 M (n = 7). This method was applied to length detection-flow injection analysis. The detection range for the flow injection analysis was 2 × 10−9–2 × 10−3 M. The detection limit (3σ) was 1.4 × 10−9 M (0.082 μg L−1), and the relative standard deviation was 1.86 at initial nickel(II) concentration of 10−6 M (n = 7).