Spectrophotometric Quantitative Analysis of Cu(II) Ion Using N,N'-bis(4-methoxysalicylidene)phenylendiamine

A N₂O₂ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine (4-CH₃O-salphen) was synthesized. Using the 4-CH₃O-salphen, the spectrophoto-metric quantitative analysis of Cu(II) ion in aqueous solution was performed. The optimum condition for the quantitative analysis of Cu(II) ion was determined as the following; the concentration of 4-CH₃O-salphen is 2.0Χ10^-4 mol/L, ratio between solvent DMSO and water is 50/50(v/v), pH is 5.5. After 1 hr water incubation at 55 .deg. C and then the absorbance measurements at 388 nm, a calibration curve (ε=3.6Χ10⁴ mol^-1cm^-1) with a correlation coefficient (R2=0.9963) was obtained in this condition. Using this optimized condition, the quantitative analysis of Cu(II) ion was performed with various samples such as hot spring water, semiconductor factory waste water and treated water from sewage treatment plant. The average value of the measured values agreed well with standard value with a range of 0.6∼5.4%. The limit of determination was 31.77 ng/mL (5.0Χ10^-7 mol/L)