Determination of Cadmium in Water Samples by FR-PAN Fluorescence Method

The objective of this study was to establish a novel method of fluorescence for the determination of cadmium using fluorescein (FR) and 1-(2-Pyridinylazo)-2-Naohthalenol (PAN). In the pH 9.75 buffer solution of the ammonia-ammonium chloride, the energy transfer between FR and the PAN can occur, which can result in the quenching of the fluorescence. The addition of Cd (II) to this system enhances the degree of quenching. This phenomenon has led to the establishment of a novel method for the determination of cadmium, which has been optimized in terms of the required experimental conditions. In the optimal experimental conditions, the fluorescence intensity of the system decreased linearly in the range of 7.81 × 10 –7 to 2.14 × 10 –5 mol L −1 . The linear regression equation used in this study was F = 123.63 + 170.65c (× 10 –6 mol L −1 ) under the correlation coefficient of 0.9951, the detection limit of 2.34 × 10 –7 mol L −1 , and the relative standard deviation of 0.18%. The proposed method was simple, sensitive, fast, and economical. The method can be employed for the determination of cadmium in real samples (tap-water, pond water and Xiangjiang River) with the results demonstrating consistency with the graphite furnace atomic absorption method (t-test). This approach offers an innovative method for the quantification of Cd (II). Graphical Abstract