title: The salicylate trapping method: is oxidation of salicylic acid solution oxygen and time dependent and metal catalysed?
abstract: For a microdialytic trapping method we systematically investigated changes in concentrations of 2,5-dihydroxy-benzoic acid (2,5-DHBA) and 2,3-dihydroxy-benzoic acid (2,3-DHBA) in freshly prepared solutions of salicylic acid (SA). The solvent was 0.9% saline exposed to different atmospheric concentrations of oxygen (0, 21, and 100%). The solutions were treated by freezing-thawing and an ultrasonic bath in presence and absence of aluminium foil. Without aluminium the concentrations of 2,5-DHBA and 2,3-DHBA kept constant over an observed period of 160 min on different levels from below 20 ng/ml to about 100 ng/ml. In presence of aluminium the concentrations increased to maximum 307 ng/ml after 160 min. Ultrasonic irradiation amplified this effect to maximum 341 ng/ml. HPLC/ECD processing and quantitative analysis of dihydroxy-benzoic acids (DHBAs) in microdialysis may be artificially influenced by varying oxygen environment and metal catalysis.
authors.affiliation: Department of Anaesthesiology, University of Regensburg, Franz-Josef-Strauss-Allee 11, Regensburg 93053, Germany. Michael.Gruber@klinik.uni-regensburg.de
authors.forename: Michael
authors.initials: M
authors.lastname: Gruber
authors.forename: Gunther
authors.initials: G
authors.lastname: Wiesner
authors.forename: Ralf
authors.initials: R
authors.lastname: Burger
authors.forename: Regina
authors.initials: R
authors.lastname: Lindner
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D002384:Catalysis; D002396:Catechols / Q000737:chemistry; D002853:Chromatography, Liquid; D005841:Gentisates / Q000737:chemistry; D062385:Hydroxybenzoates; D008670:Metals / Q000737:chemistry*; D017551:Microdialysis / Q000379:methods; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D020156:Salicylic Acid / Q000737:chemistry*; D013997:Time Factors
chemical_list: D002396:Catechols; D005841:Gentisates; D062385:Hydroxybenzoates; D008670:Metals; C009135:2,3-dihydroxybenzoic acid; D000535:Aluminum; D020156:Salicylic Acid; D010100:Oxygen; C010925:2,5-dihydroxybenzoic acid