Membranes Containing Dimethylglyoxime as Optical Sensors for Nickel Ion Detection

Abstract

Polyvinyl chloride containing dimethylglyoxime (DMG) membranes were prepared as optical sensors for detection of nickel ions based on the formation of Ni(DMG)₂ complex. The resulting pink complex was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and Ultraviolet-Visible spectroscopy (UV-Vis). Sensing performance was found to increase with increasing DMG content; however a high deviation was observed in PVC with 20%DMG membrane due to the inhomogeneous surface. The use of poly(styrene-co- methyl methacrylate) (PS-co-PMMA) as a polymer matrix provided a slightly higher sensing ability compared to that of PVC membranes. The optimized pH range for Ni²⁺ detection of PS-co-PMMA containing 20% DMG membrane was 9.0 - 10.0. The maximum reflectance occurred to Ni²⁺ concentrations above 0.8 mM. The membrane was capable of determining Ni²⁺ with a high selectivity over other selected metal ions. However, the performance decreased in the presence of both Ni²⁺ and other metal ions.