PHÁT TRIỂN PHƯƠNG PHÁP UV-Vis DỰA TRÊN PHỨC SCANDIUM-PLUMBAGIN ĐỂ XÁC ĐỊNH SCANDIUM TRONG MẪU PHÂN BÓN VÔ CƠ: TỐI ƯU HÓA VÀ ỨNG DỤNG

Tóm tắt

An UV-Vis spectroscopic method based on the complex formation reaction between Sc³⁺ ions and plumbagin was developed to determine scandium content in inorganic fertilizers. The formation of the Sc-Plumbagin complex was confirmed through UV-Vis absorption spectroscopy with a characteristic absorption band at 500 nm. Factors influencing the complex formation process and measurement were systematically investigated; the optimal conditions were determined including pH 5.5, plumbagin concentration of 10^-3 M, complexation time of 5 minutes with a stability of at least 45 minutes, and an acetonitrile:water solvent system at a ratio of 1:2 (v/v). Under these conditions, the absorbance of the complex showed a good linear relationship with Sc³⁺ concentration in the range of 1-45 ppm, with a correlation coefficient R² = 0.9988. The method had a detection limit of 0.24 ppm, a quantification limit of 0.71 ppm, and the repeatability and accuracy met the requirements of quantitative analysis. Analysis of real-world inorganic fertilizer samples showed that the proposed method was feasible, low-cost, and suitable for the determination of scandium by UV-Vis spectroscopy.