Greener analytical method for the determination of copper(II) in wastewater by micro flow system with optical sensor

Greener analytical method using micro flow system for the determination of Cu(II) in wastewater samples was designed and investigated. The micro flow system consisted of a planar glass chip with poly(dimethylsiloxane) (PDMS) top plate and fixed with fiber optic probe as optical sensor for monitoring of Cu(II) that reacted with 2-carboxy-2′-hydroxy-5′-sulfoformazyl benzene (zincon) on the chip at 605 nm. This design gave a satisfied sensitivity with a linear calibration graph over the range of 0.1–3.0 μg mL−1 of Cu(II) and correlation coefficient 0.9991. The percentage relative standard deviation was 2.5 for 10-replicate measurements and the limit of detection (LOD) was 0.1 μg mL−1. This system has been successfully applied to the determination of Cu(II) in wastewaters from electroplating industry with less reagents and samples consumption and diminutive waste generation.