title: Derivatisation of carboxylic acid groups in pharmaceuticals for enhanced detection using liquid chromatography with electrospray ionisation tandem mass spectrometry.
abstract: Tris(2,4,6-trimethoxyphenyl)phosphonium propylamine bromide (TMPP) has been used for the derivatisation of maleic, fumaric, sorbic and salicylic acids to facilitate determination using liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) in positive ion mode. Detection limits, achieved using multiple reaction monitoring mode, were 2, 4, 0.4 and 540 fmol (5 muL injection) for derivatised fumaric, sorbic, maleic and salicylic acids, respectively. In comparison, detection limits achieved in negative ion mode for the underivatised acids were 24, 51, 2, and 117 fmol, respectively. The method was successfully used for the determination of sorbic acid in a sample of Panadol. The derivatisation of salicylic acid was not as successful, probably due to poor reaction efficiency.
authors.affiliation: University of Plymouth, Speciation and Environmental Analysis Research Group, School of Earth Ocean and Environmental Sciences, Drake Circus, Plymouth PL4 8AA, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cartwright
authors.forename: Phil
authors.initials: P
authors.lastname: Jones
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Wolff
authors.forename: E Hywel
authors.initials: EH
authors.lastname: Evans
mesh_terms: D000082:Acetaminophen / Q000737:chemistry*; D018712:Analgesics, Non-Narcotic / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D002264:Carboxylic Acids / Q000032:analysis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005650:Fumarates / Q000032:analysis / Q000737:chemistry; D008298:Maleates / Q000032:analysis / Q000737:chemistry; D020156:Salicylic Acid / Q000032:analysis / Q000737:chemistry; D013011:Sorbic Acid / Q000032:analysis / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D018712:Analgesics, Non-Narcotic; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002264:Carboxylic Acids; D005650:Fumarates; D008298:Maleates; C065518:4-ethyl-1-phospha-2,6,7 trioxabicyclo(2.2.2)octane-1-oxide; D000082:Acetaminophen; C032005:fumaric acid; C030272:maleic acid; D020156:Salicylic Acid; D013011:Sorbic Acid