DOI: https://doi.org/10.55373/mjchem.v26i3.36

Keywords: Optical sensing material; hydroxymethylfurfural; honey; p-toluidine; PVA

Abstract

"The heating process, particularly at high temperatures, can destroy vitamins and enzymes in honey and lead to the production of hydroxymethylfurfural (HMF), therefore reducing the quality of honey. HMF is practically absent in fresh honey, but concentrations increase with the temperature and time of heating, as well as due to improper storage and adulteration. This research work was designed to fabricate simple optical sensing materials for HMF detection based on immobilised p-toluidine in polyvinyl alcohol (PVA) film supported on filter paper. The reflectance intensities of the immobilised reagent were measured at a wavelength range of 250 - 500 nm using a spectrophotometer. The photostability and reproducibility of the optical sensing material were good, with relative standard deviation (RSD) values of 1.9% and 2.8%, respectively, and exhibited a linear response across a wide range of HMF concentrations from 1 × 10–3 M to 7 × 10–3 M. The optimum response of the sensing material was obtained at pH 3.0. The interference study revealed no effect on the presence of glucose and fructose. The results revealed a great agreement between the fabricated optical sensing material and the high-performance liquid chromatography (HPLC) standard methods, with correlation coefficient (R2) and slope value at 0.99 and 1.02, respectively. The optical sensing material had good potential use in the quantitative determination of HMF in industrial honey with LOD 0.09 and LOQ 0.27."