Determination of total phenolic compounds in Cuban monofloral honeys by reverse flow injection analysis − Folin-Ciocalteau method

• Published in: Microchemical journal 2024-09, Vol.204, p.111008, Article 111008
• Main Authors: Franco-Ulloa, Dayné, Luaces-Alberto, Markel D., Valdés-Gonzalez, Arístides C., Agüero-Luztonó, Lissette, Baeza-Fonte, Alen N.
• Format: Article
• Language: English
• Subjects: Folin-Ciocalteau Method; Honey total phenolic compounds; Reverse Flow Injection Analysis; Solid Phase Extraction
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2024.111008

[Display omitted] •A new procedure for reverse flow injection analysis (rFIA) is developed with low consumption of Folin-Ciocalteau reagent.•The new procedure solves the controversial difference between honey antioxidant activity and the real polyphenol content.•SPE-rFIA combination allowed the determination of high concentrated polyphenols in monofloral honeys.•The developed method is significantly faster and more efficient than the traditional Folin-Ciocalteau method. Sugars represent approximately 80 % of the total composition of bee honey. They are the main interferers species of the Folin-Ciocalteau (FC) method for the determination of Total Phenolic Compounds (TPC). In the present work, a new combined methodology of Solid Phase Extraction (SPE) for sample preparation and Reverse Flow Injection Analysis (rFIA), with the use of FC reagent (FCR) was developed. SPE was performed with C18 BAKERBOND cartridges, while a two-channel rFIA optimized system was established for measurements. In this configuration sample and NaOH solution (0.1 molL-1) flow in two different channels, while FC reagent is injected. The detection was carried out in a flow cell located into a UV–Vis spectrophotometer at 760 nm. The results, expressed as Gallic acid equivalent (GAE), ranged from 75 to 107.9 and 215–242 mg Kg−1 for Leñatero and Guao de Costa honeys respectively used as experimental samples. Recoveries for honey samples were of 93–96 % (CV