title: Determination of caffeoylquinic acids in feed and related products by focused ultrasound solid-liquid extraction and ultra-high performance liquid chromatography-mass spectrometry.
abstract: A method to determine caffeoylquinic acids (CQAs) in three sources (herbal extract, feed additive and finished feed) using for the first time focused ultrasound solid-liquid extraction (FUSLE) followed by ultra-high performance liquid chromatography (UPLC) coupled to quadrupole-time of flight mass spectrometry is presented. Pressurized liquid extraction (PLE) was also tested as extraction technique but it was discarded because cynarin was not stable under temperature values used in PLE. The separation of the CQAs isomers was carried out in only seven minutes. FUSLE variables such as extraction solvent, power and time were optimized by a central composite design. Under optimal conditions, FUSLE extraction was performed with 8mL of an 83:17 methanol-water mixture for 30s at a power of 60%. Only two extraction steps were found necessary to recover analytes quantitatively. Sensitivity, linearity, accuracy and precision were established. Matrix effect was studied for each type of sample. It was not detected for mono-CQAs, whereas the cynarin signal was strongly decreased due to ionization suppression in presence of matrix components; so the quantification by standard addition was mandatory for the determination of di-caffeoylquinic acids. Finally, the method was applied to the analysis of herbal extracts, feed additives and finished feed. In all samples, chlorogenic acid was the predominant CQA, followed by criptochlorogenic acid, neochlorogenic acid and cynarin. The method allows an efficient determination of chlorogenic acid with good recovery rates. Therefore, it may be used for screening of raw material and for process and quality control in feed manufacture.
authors.affiliation: Department of Chemistry, University of La Rioja, Madre de Dios 51, E-26006 Logroño La Rioja, Spain. Electronic address: maria-teresa.tena@unirioja.es.
authors.forename: M T
authors.initials: MT
authors.lastname: Tena
authors.affiliation: Department of Chemistry, University of La Rioja, Madre de Dios 51, E-26006 Logroño La Rioja, Spain.
authors.forename: M P
authors.initials: MP
authors.lastname: Martínez-Moral
authors.affiliation: Igusol Advance S A, c/La Losa 7-2, 26370, Navarrete La Rioja, Spain.
authors.forename: P W
authors.initials: PW
authors.lastname: Cardozo
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D005504:Food Analysis / Q000379:methods*; D059625:Liquid-Liquid Extraction; D013058:Mass Spectrometry; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D052616:Solid Phase Extraction; D013016:Sound
chemical_list: C472707:caffeoylquinic acid; D011801:Quinic Acid
keywords: Caffeoylquinic acids; Chlorogenic acid; Cynarin; Feed; Liquid chromatography; Mass spectrometry