摘要
A method was developed for the analysis of ester-linked phenolic acids in forage samples using extraction by an ultrasound-assisted treatment and quantification by HPLC with a UV-VIS detector. A reversed-phase C18 column was used for developing the method and the optimal condition was established with isocratic elution using acetonitrile/methanol/H3PO4 pH 2.08 (13:12.5:74.5) as the mobile phase. To reduce the time of sample processing, the extraction of ester-linked phenolic acids was studied using ultrasound bath and the results were then compared with those from an extraction usual using alkaline hydrolysis (20°C for 24 h). The method was valued through external and internal calibration. Internal calibration using o-coumaric acid as internal standard and m-coumaric acid as surrogate internal standard showed better results. The detection limits were of 0.09 and 0.04 mg●L-1 for p-coumaric and ferulic acids, respectively. The proposed method showed a good linear dynamic range (3.00 - 30.00 mg●L-1) for the analytes. The usefulness of the methodology was demonstrated by addition-recovery experiments using forage samples and values were in the 83 to 99% range. The extraction of ester-linked phenolic acids by 120 minutes of ultrasound bath was faster and more reproducible than alkaline hydrolysis (20°C for 24 h).
A method was developed for the analysis of ester-linked phenolic acids in forage samples using extraction by an ultrasound-assisted treatment and quantification by HPLC with a UV-VIS detector. A reversed-phase C18 column was used for developing the method and the optimal condition was established with isocratic elution using acetonitrile/methanol/H3PO4 pH 2.08 (13:12.5:74.5) as the mobile phase. To reduce the time of sample processing, the extraction of ester-linked phenolic acids was studied using ultrasound bath and the results were then compared with those from an extraction usual using alkaline hydrolysis (20°C for 24 h). The method was valued through external and internal calibration. Internal calibration using o-coumaric acid as internal standard and m-coumaric acid as surrogate internal standard showed better results. The detection limits were of 0.09 and 0.04 mg●L-1 for p-coumaric and ferulic acids, respectively. The proposed method showed a good linear dynamic range (3.00 - 30.00 mg●L-1) for the analytes. The usefulness of the methodology was demonstrated by addition-recovery experiments using forage samples and values were in the 83 to 99% range. The extraction of ester-linked phenolic acids by 120 minutes of ultrasound bath was faster and more reproducible than alkaline hydrolysis (20°C for 24 h).
基金
the FAPEMIG(Fun-dacao de Amparo a Pesquisa do Estado de Minas Gerais),CNPq(Conselho Nacional de Desenvolvimento Cien-tifico e Tecnologico),CAPES(Coordenacao de Aper-feicoamento de Pessoal de Nivel Superior)and PRO-PESQ/UFJF(Pro-Reitoria de Pesquisa da Universi-dade Federal de Juiz de Fora)for financial support
