A New Enrichment Method for Quantification of 5-Hydroxymethylfurfural by Indirect Flame Atomic Absorption Spectrometry in Honey and Jam Samples

Abstract

Background: Because of increasing amounts of 5-hydroxymethylfurfural (5-HMF) in processed foods and the complexity of the matrix, monitoring of trace 5-HMF requires accurate and reliable methods. Hence, an efficient sample pretreatment procedure is necessary for extraction and preconcentration of 5-HMF from the matrix. Objective: In this study, a new and efficient sample preparation method utilizing ultrasound-assisted-cloud point extraction (UA-CPE), indirectly followed by flame atomic absorption spectrometry (FAAS), was introduced for the monitoring of trace amounts of 5-HMF in honey and jam samples. Method: With this method, hydroxylamine was used as a derivatizing agent in the presence of Mn(II) and an anionic surfactant, SDS for extraction of 5-HMF at pH 9.0. For dispersing reagents in sample solution, low amounts of mixed surfactant, triton X-45 and SDS were mixed and fast-injected into the extraction media. A cloudy solution formed, and after reaction of 5-HMF with reagents, the cloudy solution was centrifuged. The extracted 5-HMF in the surfactant-rich phase was dissolved in acidic acetone and indirectly analyzed by FAAS. Results: The method showed a detection limit of 1.27 lg/L in linear working range of 4–240 lg/L, good precision (2.3–6.5%), and recovery rates (93.5–97%) after preconcentration of 70-fold. Conclusions: Within this study, an accurate and reliable method for the indirect quantification of 5-HMF in selected samples was successfully developed with a sensitivity improvement factor of 30.6. Highlights: The figures of merit for the developed indirect method were appropriate. The applicability of the method for the analysis of 5-HMF in processed foods was excellent.