A novel spectrophotometric method for the determination of copper ion by using a salophen ligand, N,N′-disalicylidene-2,3-diaminopyridine

Peer review under responsibility of Taibah University.

Figures & data

Fig. 1 Planar intramolecular H-bonded optimized structure of H₂IF.

Fig. 2 Absorption spectra of H₂IF (blue) and H₂IF-copper(II) complex (red).

Fig. 3 Dependence of the absorbance of H₂IF-copper(II) complex on pH.

Fig. 4 Calibration curve for spectrophotometric determination of copper(II).

Table 1 Analytical results of water samples and the recovery of spiked analyte, and standard reference materials.

Sample	Added (μg L^−1)	Found^b (μg L^−1)	Recovery	Certified (μg L^−1)
River water^a	–	60.72(0.32)
	25.00	86.46(0.24)	102.96
Sea water^a	–	50.45(0.35)
	50.00	99.25(0.18)	98.50
C12X3500	–	24.82(0.27)		25.00
SPS-WW1	–	392.45(0.12)		400.00

a Samples were collected at Samsun, Turkey.

b Values in parentheses are the relative standard deviations for n = 3 with a confidence of 95%.

Fig. 5 Job’s plot for the mixtures of H₂IF and Cu(II) solutions maximized at an approximately 1:1 metal to ligand ratio.

Table 2 Comparison of the present spectrophotometric data to others in the determination of copper(II).

ε (L mol^−1 cm^−1)	Beer’s law range	λmax	Reaction time (min)	Ref.
2.7 × 10^4	6.6–330 μmol L^−1	502	2	1
0.4 × 10^5	2.0–14 μg mL^−1	375	5	2
4.37 × 10^5	4.0–115 ng mL^−1	608	10	3
0.87 × 10^3	10–80 μg mL^−1	445	15	4
1.08 × 10^4	0.31–6.35 mg L^−1	390	–	5
2.8 × 10^3	0.15–0.6 mg L^−1	240	–	6
0.158 × 10^4	1–10 mg L^−1	398	–	7
1.46 × 10^5	6.35–318 μg L^−1	410	1	Current work