title: Feasibility study of online supercritical fluid extraction-liquid chromatography-UV absorbance-mass spectrometry for the determination of proanthocyanidins in grape seeds.
abstract: Online coupling of supercritical fluid extraction (SFE) with liquid chromatography (LC)-UV absorbance-electrospray ionization (ESI)-mass spectrometry (MS) is evaluated for the determination of proanthocyanidins in grape seeds. The solid-phase intermediate trap is optimized in order to enhance the collection efficiency for the extracted polar components. Pure supercritical CO2 is used first to remove the oil in the seeds. Then methanol-modified CO2 is used to remove the polar components (e.g., phenolic compounds). Catechin and epicatechin (90%) are extracted out of the de-oiled after 240 min with 40% methanol as a modifier. Both singly-linked (B-type) and doubly-linked (A-type) procyanidins are identified by LC-ESI-MS, as well as their galloylated derivatives. The hyphenated system combines the extraction, separation, and detection in series. The experimental design minimizes the chance of analyte oxidation, degradation, and contamination. The traditional off-line SFE-LC method is also studied for comparison with the online method. Both advantages and disadvantages are observed for the online mode.
authors.affiliation: Department of Chemistry, Virginia Tech, Blacksburg, VA 24061-0212, USA.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Wang
authors.forename: Mehdi
authors.initials: M
authors.lastname: Ashraf-Khorassani
authors.forename: Larry T
authors.initials: LT
authors.lastname: Taylor
mesh_terms: D002392:Catechin / Q000032:analysis; D002853:Chromatography, Liquid / Q000379:methods*; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D005240:Feasibility Studies; D005638:Fruit / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D009862:Online Systems; D044945:Proanthocyanidins / Q000032:analysis*; D012639:Seeds / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry*
chemical_list: D044945:Proanthocyanidins; D002392:Catechin