title: Determination of shikimate in crude plant extracts by micellar electrokinetic capillary chromatography.
abstract: A method based on micellar electrokinetic capillary chromatography (MECC) has been developed for the determination of shikimate in water and crude plant extracts. The analytes are separated in a cholate-taurine buffer by MECC at pH 7.3 and measured by direct UV detection at 206 nm. Shikimate showed linearity up to 12.5 mM, with a squared correlation coefficient (r(2)) of 0.9997. The method has concentration limit of detection (cLOD) and concentration limit of quantification (cLOQ) at 24.4 and 67.8 microM, respectively, corresponding to detection in the femtomol range. The number of theoretical plates (N) was estimated to 245,000 for the optimized system using a capillary with an effective length of 560 mm. The method was tested on plant samples by measuring the shikimate content in leaves of rapeseed plants grown in hydroponic solutions containing the herbicide glyphosate, a well-known inhibitor of the shikimate pathway. In crude extracts of these plants, shikimate was found to accumulate in the leaves, confirming earlier reports of shikimate as a potential biomarker for glyphosate treatment. The method now developed was also able to detect shikimate-3-phosphate, but this compound was not accumulated in glyphosate inhibited plants as found for shikimate.
authors.affiliation: Department of Natural Sciences, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
authors.forename: Iben Lykke
authors.initials: IL
authors.lastname: Petersen
authors.forename: Keld Ejdrup
authors.initials: KE
authors.lastname: Andersen
authors.forename: Jens Christian
authors.initials: JC
authors.lastname: Sørensen
authors.forename: Hilmer
authors.initials: H
authors.lastname: Sørensen
mesh_terms: D029741:Brassica rapa / Q000737:chemistry / Q000187:drug effects; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006540:Herbicides / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry / Q000187:drug effects; D012765:Shikimic Acid / Q000032:analysis* / Q000737:chemistry; D000097797:Glyphosate
chemical_list: D005998:Glycine; D006540:Herbicides; D010936:Plant Extracts; D012765:Shikimic Acid; D000097797:Glyphosate