Analytical Sciences

Measurement of Free Copper(II) Ions in Water Samples with Polyvinyl Alcohol as a Binding Phase in Diffusive Gradients in Thin-films

Hongtao FAN, Yuqian BIAN, Dianpeng SUI, Guifeng TONG, and Ting SUN

Department of Chemistry, Northeastern University, Shenyang 110004, China

A technique for the selective measurement of diffusive gradients in thin-films (DGT) for free Cu²⁺ ions was developed using a 0.030 M solution of polyvinyl alcohol (PVA) as the liquid binding phase with the liquid-type DGT devices (PVA DGT). The PVA DGT had a substantial binding capacity at pH 5.6 − 8.6 and concentrations of competitive Na⁺ up to 0.7 M. The measurements of PVA DGT and cupric ion selective electrode (Cu-ISE) for free Cu²⁺ in synthetic river water (recovery = 97.51 ± 2.58% for PVA DGT and recovery = 98.25 ± 1.46% for Cu-ISE), in spiked river water (recovery = 24.99 ± 3.55% for PVA DGT and recovery = 26.32 ± 3.33% for Cu-ISE) and in spiked industrial wastewater (recovery = 4.21 ± 3.13% for PVA DGT and recovery = 5.10 ± 2.78% for Cu-ISE) were equivalent. The results showed that PVA DGT could measure selectively the free Cu²⁺ ion concentrations in water samples.

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