Author(s)

Mellina Damasceno Rachid Santos, Aline de Paula Vitor, Jailton da Costa Carneiro, Domingos Sávio Campos Paciullo, Renato Camargo Matos, Maria Auxiliadora Costa Matos

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NUPIS (Núcleo de Pesquisa em Instrumenta??o e Separa??o Analíticas), Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, 36038-300, Juiz de Fora, MG, Brazil.

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).

Ultrasound Bath, Phenolic Acids, Forage, Internal Calibration

M. Santos, A. Vitor, J. Carneiro, D. Paciullo, R. Matos and M. Matos, "Use of Ultrasound Bath in the Extraction and Quantification of Ester-Linked Phenolic Acids in Tropical Forages," American Journal of Analytical Chemistry, Vol. 2 No. 3, 2011, pp. 344-351. doi: 10.4236/ajac.2011.23042.