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 procedur e for the simultaneous quantification of 5-HMF, furfural, 5-O-caffeoyl quinic acid and caffeine in green and roasted coffee samples. The samp le preparation was simple, only involving a boiled water extraction fo llowed by filtration. ?The chromatographic separation was achieved usi ng a reversed-phase column Spherisorb ODS2 (5 mu m; 25.0 x 0.46 cm). G radient elution was carried out using water+acetic acid (0.2%) (A) and methanol (B). The effluent was monitored by a diode-array detector an d chromatograms were recorded at 280 nm. :The determinations were perf ormed 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 obtaine d (n=10) was better than CV% 0.52, 0.62, 0.14, and 0.50 for 5-HMF, fur fural, 5-O-caffeoylquinic acid, and caffeine, respectively: for green coffee, it was better than 0.76 for 5-O-caffeoylquinic acid and 0.89 f or 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, furfur al, 5-O-caffeoylquinic acid, and caffeine, respectively, For green cof fee sample, recovery values were between 73 and 74% for 5-O-caffeoylqu inic acid and between 94 and 98% for caffeine.