Women in science: Towards a copper-azophloxine inorganic complex for the selective naked-eye detection of pyrophosphate in water

Indicator displacement assay is a well-known methodology reported for the detection of analytes. It is very easy to perform, especially with high school students. Since the methodology is simple, wide libraries can be generated with such a strategy. Potentially, it could provide interesting chemosensors never reported in the literature for the naked-eye detection of a specific analyte of interest. Here for a maturity work, we investigated the possibility to detect pyrophosphate with an indicator displacement assay. In first instance, we combined copper with azophloxine to form an inorganic complex in water. The chemosensor is not reported in the literature and is able to detect pyrophosphate at micromolar concentration with a concomitant color change. In second instance, we screened a collection of anions in order to investigate the selectivity of our chemosensor. Our results showed that our sensor is very specific to pyrophosphate and doesn’t suffer from interactions with phosphate or carbonate. Taken together our results indicates that real research with socially relevant results can be conducted at high school by using smart methodologies and very modest resources.