Simultaneous determination of 15 phenolic compounds and caffeine in teas and mate using RP-HPLC/UV detection: Method development and optimization of extraction process

• Published in: Food chemistry 2015-04, Vol.172, p.469-475
• Main Authors: Bae, In Kyung, Ham, Hyeon Mi, Jeong, Min Hee, Kim, Dong Ho, Kim, Ho Jin
• Format: Article
• Language: English
• Subjects: Caffeine; Caffeine - analysis; Camellia sinensis - chemistry; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Ethanol - chemistry; Limit of Detection; Phenolic compounds; Phenols - analysis; Plant Extracts - analysis; Reproducibility of Results; Response surface methodology; RP-HPLC/UV; Tea; Tea - chemistry; Validation
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.09.050

•Extraction process was optimized by response surface methodology (RSM) based on a central composite design (CCD).•RP-HPLC/UV method was developed for simultaneous determination of 15 phenolic compounds and caffeine in teas and mate.•Reliability of the developed method was confirmed by validation test. A reversed-phase high performance liquid chromatographic coupled to ultraviolet detection (RP-HPLC/UV) method was developed for simultaneous determination of 15 phenolic compounds and caffeine in TEAS (green tea, oolong tea, black tea and mate). Furthermore, the extraction process of total phenolic contents (TPC) from TEAS were optimized using response surface methodology (RSM) based on a central composite design (CCD) and then applied to extraction of TEAS. The best conditions obtained using the model were as follow: green tea – extraction time of 123min, extraction temperature of 70°C and ethanol concentration of 75%, oolong tea – extraction time of 98min, extraction temperature of 70°C and ethanol concentration of 69%, black tea – extraction time of 105min, extraction temperature of 71°C and ethanol concentration of 63%, and mate – extraction time of 103min, extraction temperature of 71°C and ethanol concentration of 61%. Among the extraction methods used in this study, heat-reflux extraction was found to result in the highest values of TPC. The chromatographic peaks of the 16 studied compounds were successfully identified by comparing their retention time and UV spectra with the reference standards. Method validation was performed by means of linearity, sensitivity, selectivity, accuracy and precision. The developed method was found to be simple, specific and reliable and is suited for routine analysis of phenolic compounds and caffeine in TEAS.