This study introduces a novel flow injection analysis (FIA) method for rapid, accurate detection of Cu(II) ions using calcium hexacyanoferrate and potassium chloride. Using the NAG-4SX3-3D Analyzer, the sensor's energy response was evaluated, yielding consistent and reliable results. The study established a linear range for copper(II) detection from 0.005 mM to 5.0 mM (0.318-317.75 mg L-1), with a low relative standard deviation (RSD%) of less than 0.23% at 1.5 mM and 4.5 mM across nine replicates. The limit of detection (LOD) was determined to be 12.901 ng per sample (12.901 µgL-1 based on a 1.0 mL injection) through progressive dilution analysis, using the minimum concentration on the calibration curve. Detector FIA was photometric/turbidimetric at 620 nm (bandpass ~10 nm). The linear dynamic range (LDR) showed a strong correlation (r = 0.9853) and a high coefficient of determination (R² = 99.07). A comparison with the traditional UV-spectrophotometric method at λmax = 296nm underscored the technique's heightened sensitivity, efficient use of chemicals, and superior results. Additionally, the accuracy of the copper concentration results in the samples was validated using UV spectrophotometry and flame atomic absorption spectroscopy (F-AAS) after dilution, with a calibration range of 0.05–5.0 mg L⁻¹.
Mohammed et al. (Sun,) studied this question.