2.3. HPLC analysis
For HPLC analysis, samples were prepared by dissolving 1.0 g honey or syrup in 100 ml of MilliQ water and homogenised for 10 min in an ultrasound water bath or overnight at room temper- ature. The sample solution was filtered through 0.45 lm mem-
brane into auto sampler vials for HPLC analysis.
All HPLC analyses were accomplished with an Agilent 1200 liquid chromatography system (Agilent Technologies Deutschland, Waldbronn, Germany), equipped with a vacuum degasser, a quaternary solvent delivery pump, a thermostated column
compartment and a refractive index detector (RID). All HPLC analyses were carried on a Carbomix Ca-NP5: 8% column (7.8 Â 300 mm, 5 lm) at 80 °C. Pure water was used as mobile phase in elution. The flow-rate was 0.3 ml/min. 30 ll of sample solution was injected for each HPLC analysis. For the analysis of authentic honey and syrup samples, each sample was analysed twice in triplicate. For the determination of linearity of peak height, six replicate anal- yses at each content level of syrup were performed. Finally, for the commercial samples inspection, all samples were analysed in trip- licate at certain concentration