An Eco-Friendly, Interference, and Solvent Free Surfactant-Assisted Dual-Wavelength β-CorrectionSpectrometric Method for Total Determination and Speciation of Cu2+ Ions in Water.

Abstract

Spectral interference through the presence of uninformative variables, excess reagents, and complications in the refinement of the analyte signal is common in the quest to identify complex species in real samples. Therefore, an economical green, facile, and sensitive strategy has been developed for Cu²⁺ detection using the anionic surfactant sodium dodecylsulphate- (SDS-) assisted dual-wavelength β-correction spectrophotometric strategy combined with the chromogenic reagent zincon (ZI). The low limits of detection (LOD) and quantification (LOQ) of Cu²⁺ using ordinary (single wavelength) spectrophotometry were 0.19 (3.02) and 0.63 (10.0) μgmL^-1, and these values were improved to 0.08 (1.27) and 0.26 μgmL^-1 (4.12 μM)) using β-correction (dual wavelength) spectrophotometry, respectively. The LOD and LOQ were improved from 0.08 (1.27) and 0.26 (4.12) μgmL^-1 to 0.02 (0.32) and 0.08 μgmL^-1 (1.27 μM) using SDS-assisted dual-β-correction spectrometry, respectively. Ringbom, s, and the corrected absorbance (A_c) versus Cu²⁺ concentration plots were linear over the concentration range 1.10-2.4 (17.4-38.1) and 0.50-2.40 μgmL^-1 (7.94-38.1 μM), respectively. Sandell's sensitivity index of 3.0 × 10^-3 μg/cm² was achieved. The selectivity was further confirmed via monitoring the impact of common diverse ions and surfactants on the corrected absorbance. Total determination and Cu²⁺ speciation in water were favorably implemented and validated by ICP-OES at 95% (P=0.05). Satisfactory Cu²⁺ recoveries in tap (92.2-98.0%) and mineral (105-111.0%) water samples were achieved. The sensing system is simple, reliable, sensitive, and selective for Cu²⁺ detection.