2.3.2. Purification of the extracts with SPE columns
Five milliliters of honey sample solutions (diluted 1:1 w/v) after sonication in ultrasonic bath for 10 min were inserted into SPE columns, subsequently honey solution has been left to completely draw off the SPE and then the columns were rinsed with 5 mL distilled water. All eluate volume was then quantitatively transferred into 50 mL volumetric flask, 2.5 mL Folin-Ciocalteau reagent was added and 7.5 mL 20% Na2CO3 solution. After filling with distilled water to mark and careful agitation the reaction solution was left to stand at laboratory temperature for 20 min and then measured on the UV–VIS spectrophotometer Helios g at wave length l ผ765 nm against blank. The determined values (from three parallel determinations) for this saccharides portion were consequently subtracted from values measured in crude samples to obtain corrected TP values. values of total polyphenols.