Effect of pH on the characteristics of potassium permanganate–luminol CL reaction in the presence of trace aluminum(III) and its analytical application

At pHs ≥ 11.45, trace Al was found to enhance the CL from luminol–KMnO4 system. However, at pHs ≤ 10.42, it was found to inhibit strongly the CL from luminol–KMnO4 system. The effect of pH, luminol and potassium permanganate concentrations on the kinetic characteristics of CL system was investigated in the presence of trace Al. On this basis, a flow injection inhibition chemiluminescence method was established for the determination of trace Al in this study. Under optimized conditions, the CL decreased linearly with Al(III) concentration in the range of 8–500 μg L−1 and the detection limit (3σ) of 2 μg L−1. The relative standard deviation (R.S.D.) is 3.6% for 100 μg L−1 Al(III) (n = 11). The method has been applied to the determination of trace Al in real water samples with satisfactory results without the pretreatment of samples. The results given by the proposed method are in good agreement with those given by ICP-AES detection method.