Quantification of 5-hydroxymethylfurfural in honey samples and acidic beverages using spectrophotometry coupled with ultrasonic-assisted cloud point extraction

Abstract

The simple, cost-effective and fast preconcentration method using ultrasonic-assisted cloud point extraction (UA-CPE) has been developed for determination of 5-hydroxymethylfurfural (5-HMF) by means of spectrophotometry. The method is based on selective complex formation of 5-HMF with p-nitrophenylhydrazine (p-NPH) in presence of sodium dodecyl sulfate (SDS) as auxiliary ligand with counter charge at pH 4.0,and then extracted into the non-ionic surfactant, polyethylene glycol 4-tert-octylphenyl ether (Triton X-45). Under the optimized conditions, the calibration graph was rectilinear in the range of 6.5–275μgL−1 with two different calibration slopes in two linear regions with changing sensitivity. The limits of detection and quantification (LOD and LOQ) (3σblank/m and 10σblank/m) was 1.96 and 6.50μgL−1, and the precision (as RSD) for determination of 25, 75 and 150μgL−1 of 5-HMF was in range of 2.10–3.65%. The method was successfully applied to the accurate and reliable determination of 5-HMF as an indicator of honey quality in different honey and acidic beverage samples. The accuracy of the method was statistically established by recoveries of spiked samples. The results of analysis by the developed method were found to be in good agreement with those obtained by the modified spectrophotometric White method.