FerroSense: A flexible polymeric chemosensor for low-cost recognition of potassium hexacyanoferrate using mixture of silver nanoparticles and sodium isopropyl xanthate as organic-inorganic hybrid optical probe

Potassium hexacyanoferrate is an oxidizing agent known for its ability to oxidize a variety of substrates, including antibiotics, monosaccharides, amines, alcohols, and amino acids, under both acidic and alkaline conditions. It is widely used in fields such as blueprint production, photography, organic chemistry, and food safety monitoring, as well as in biosensors and glucometers to regulate redox potential. Given its numerous applications and potential health and environmental impacts, there is a critical need for rapid, cost-effective, and user-friendly detection methods that offer high sensitivity and selectivity. In this study, two portable colorimetric sensors were developed for the selective recognition of potassium hexacyanoferrate. The optical sensor employs mixture of silver nanoprisms (AgNPrs) combined with sodium isopropyl xanthate (SIPX) as novel hybrid optical nanoprobe, that immobilized on parafilm (PF) and polymethyl methacrylate (PMMA). Using synergetic plasmonic amplification of AgNPrs and SIPX, detection of Potassium hexacyanoferrate is accomplished by colorimetric digital image analysis via the Color Picker app, which installed on iPhone 13 smartphone and led to achieving a low limit of quantification of 100 μM. This method exhibits suitable selectivity, which confirmed successful interaction between potassium hexacyanoferrate and the AgNPrs/sodium isopropyl xanthate. Significant change in the absorption spectrum, confirmed by UV–visible spectrophotometry, enabling detection of analyte across a dynamic range from below 100 μM to 30 mM. The sensor has shown practical utility in various bioanalytical contexts and is supported by the micro-scale PF-based colorimetric device (μPFCD) for efficient on-site analysis of Potassium hexacyanoferrate. This represents the first use of AgNPrs/SIPX for detecting potassium hexacyanoferrate using smartphone-assisted colorimetric and spectrophotometric sensing strategy. The design allows for direct quantification without complex sample preparation, making it a promising tool for real-time monitoring in different environments. This method significantly enhances workplace safety, environmental monitoring, and chemical hazard detection, offering a valuable platform for detecting potassium hexacyanoferrate and other hazardous chemical species.