Transparent polymer sensor for visual and photometrical detection of thiocyanate in oilfield water

A novel colorimetric sensor has been proposed for sensitive and accurate visual and spectrophotometric detection of thiocyanate using polymethacrylate matrix, which also has the potential for use with samples without pretreatment. The determination method is based on shaping of a Fe3+-thiocyanate colored complex into a transparent polymer matrix, followed by measurement of absorbance at 490 nm. The principle of this colorimetric sensor is not ordinary colorimetry, but a new colorimetric strategy that combines solid phase extraction and spectrophotometric determination of thiocyanate following completion of the color change processes. The method ensures determination of 0.8-30.0 mg L-1 of thiocyanate with the detection limit of 0.3 mg L-1. The proposed simple method makes it possible to determine visually in the concentration above 6.0 mg L-1 using a color scale. The test results show that the polymethacrylate matrix can be used for determination of thiocyanate in oilfield water.