Preparation and characterization of a novel Co(II) optode based on polymer inclusion membrane

- Green analytical approach of the system (low reagent consumption and minimal waste generated).
- Green analytical approach during preparing the membrane (a greener solvent of 2-methyltetrahydrofuran was used instead of tetrahydrofuran).
- Simplification of the sensing system (rapid response of the analyte, provide higher selectivity as compared to common optical sensing system, simple system set up and inexpensive system to run).
- The constructed optode is applicable for determination of analyte (in this case Co(II) ion).

A greener analytical procedure based on automated flow through system with an optical sensor is proposed for determination of Co(II). The flow through system consisted of polymer inclusion membrane (PIM) containing potassium thiocyanate (KSCN) that was placed between the measuring cell and fixed with optical sensor probe as an optical sensor for monitoring of Co(II) at 625 nm. In the presence of Co(II) ions, the colourless membrane changes to blue. The sensing membrane was prepared by incorporating SCN into a non plasticized PIM. The prepared PIM were found to be homogenous, transparent and mechanically stable. The optode shows reversible optical response in the range of 1.00 × 10−6 - 1.00 × 10−3 mol L−1 with detection limit of 6.10 × 10−7 mol L−1. The optode can be regenerated by using 0.1 mol L−1 of ethylenediaminetetraacetic acid (EDTA). The main parameters of the computer controlled flow system incorporating the flow-through optode, a multi-port selection valve and peristaltic pump were optimized too. The calculated Relative Standard Deviation (R.S.D) of the repeatability and reproducibility of the method are 0.76% and 4.73%, respectively. This green system has been applied to the determination of Co(II) in wastewater samples with reduced reagents and samples consumption and minimum waste generation.

113