Development of a low-cost colorimetric paper-based spot test for the environmental monitoring of phenolic pollutants

Abstract

This work reported the development, prototyping and validation of a low-cost colorimetric paper-based sensor for the analysis of phenolic contaminants in waterbodies. The device was constructed using chromatographic paper and the chromogenic probe was Folin Ciocalteu reagent. Results evidenced that undiluted chromogen solution and 15% sodium carbonate allowed the maximum performance of the sensor, which exhibited adequate linearity between 100 mg l−1 and 1000 mg l−1 and limits of detection and quantification of 25 and 1000 mg l−1, respectively for the phenolic probes herein used (e.g. gallic acid, catechol, pyrogallol and vanillin), as well as adequate recovery for gallic acid upon recovery test. Moreover, the paper-based sensor was used to evaluate a real sample, and results were compared to a standard test, thereby presenting no statistically significant difference (i.e. 505.21 mg l−1 for the standard test and 517.49 mg l−1 for the paper-based sensor, p > 0.05). The findings therefore suggests that the biosensor herein described is a low-cost and valuable alternative to detect and quantify phenolic contaminants in waterbodies.

Keywords

• Folin Ciocalteu
• Toxicity
• Waterbodies
• Textile industry
• Hydroxyl