Development of an HPLC/diode-array detector method for simultaneous determination of 5-HMF, furfural, 5-O-caffeoylquinic acid and caffeine in coffee

This paper describes an interference-free reversed-phase HPLC procedure for the simultaneous quantification of 5-HMF, furfural, 5-O-caffeoylquinic acid and caffeine in green and roasted coffee samples. The sample preparation was simple, only involving a boiled water extraction followed by filtration. ?The chromatographic separation was achieved using a reversed-phase column Spherisorb ODS2 (5 mu m; 25.0 x 0.46 cm). Gradient elution was carried out using water+acetic acid (0.2%) (A) and methanol (B). The effluent was monitored by a diode-array detector and chromatograms were recorded at 280 nm. :The determinations were performed in the linear ranges 0.25-10 mu g/mL, 0.1-10 mu g/mL, 2.5-100 mu g/mL, 0.25-200 mu g/mL for 5-HMF, furfural, 5-O-caffeoylquinic acid, and caffeine, respectively. Extensive quality assurance of the method was performed by the standard additions method in both coffee matrices (green and roasted coffee). For roasted coffee, the precision obtained (n=10) was better than CV% 0.52, 0.62, 0.14, and 0.50 for 5-HMF, furfural, 5-O-caffeoylquinic acid, and caffeine, respectively: for green coffee, it was better than 0.76 for 5-O-caffeoylquinic acid and 0.89 for caffeine. For roasted coffee samples, recovery values were between 85 and 104%, 87 and 103%, 88 and 94%, and 74 and 77% for 5-HMF, furfural, 5-O-caffeoylquinic acid, and caffeine, respectively, For green coffee sample, recovery values were between 73 and 74% for 5-O-caffeoylquinic acid and between 94 and 98% for caffeine.