Development of a Colorimetric Sensor Array for Rapid Detection of Adulterants in Honey Sold in North West Nigeria

Honey adulteration using sucrose syrup, corn syrup, and rice syrup is economically motivated and widespread in Nigerian markets, causing financial losses to genuine honey producers and depriving consumers of the authentic nutritional and medicinal properties of natural honey, yet rapid field-deployable detection tools are unavailable to regulators and producers. This study develops a colorimetric sensor array for the rapid detection of common honey adulterants, validated against honey samples from North West Nigeria. The sensor array is constructed from a panel of twelve chemically diverse dye reagents cross-reactive to carbohydrates, organic acids, phenolic compounds, and enzyme markers. Colour response patterns upon honey sample addition are captured by flatbed scanner imaging and converted to RGB data matrices. Authentic monofloral and polyfloral honey samples from beekeepers in Zamfara, Sokoto, and Kebbi States are characterised by high-performance liquid chromatography sugar profiling, enzyme activity assays (diastase and invertase), and carbon isotope ratio analysis by isotope ratio mass spectrometry as gold-standard authentication references. Adulterated samples are prepared by spiking authentic honey with controlled levels of sucrose syrup, high-fructose corn syrup, and rice syrup at one to fifty percent adulteration levels. Linear discriminant analysis and support vector machine classification models are trained on the sensor array colour data to discriminate authentic from adulterated honey and identify adulterant type. Cross-validation accuracy and leave-one-out validation metrics are reported. Findings contribute a scalable low-cost honey authentication tool for use in regulatory market surveillance in the North West geopolitical zone. Keywords: honey adulteration, colorimetric sensor array, authentication, North West Nigeria, chemometrics