title: Ferrocenoyl piperazide as derivatizing agent for the analysis of isocyanates and related compounds using liquid chromatography/electrochemistry/mass spectrometry (LC/EC/MS).
abstract: Ferrocenoyl piperazide is introduced as a new pre-column derivatizing agent for the analysis of various isocyanates in air samples using reversed-phase liquid chromatographic separation, electrochemical oxidation/ionization, and mass spectrometry. The nonpolar derivatives can be separated well using a phenyl-modified stationary phase and a formic acid/ammonium formate buffer of pH 3, which yields excellent separations, especially for one problematic group of isocyanates consisting of 2,4- and 2,6-toluylenediisocyanate (2,4- and 2,6-TDI) and hexamethylenediisocyanate (HDI). Electrochemical oxidation at low potentials (0.5 V versus Pd/H(2)) leads to formation of charged products, which are nebulized in a commercial atmospheric pressure chemical ionization (APCI) source, with the corona discharge operated only at low voltage. Limits of detection between 6 and 20 nmol/L are obtained for the isocyanate derivatives, and calibration is linear over at least two decades of concentration. The method is applied for the analysis of air after thermal degradation of a polyurethane foam, and it is demonstrated that it is suitable as well for the analysis of carboxylic acid chlorides and of isothiocyanates.
authors.affiliation: Department of Chemical Analysis and MESA(+), Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: Bettina
authors.initials: B
authors.lastname: Seiwert
authors.forename: Hartmut
authors.initials: H
authors.lastname: Henneken
authors.forename: Uwe
authors.initials: U
authors.lastname: Karst
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry*; D017953:Isocyanates / Q000737:chemistry*; D000075163:Metallocenes; D016273:Occupational Exposure / Q000032:analysis; D010880:Piperidines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D005296:Ferrous Compounds; D017953:Isocyanates; D000075163:Metallocenes; D010880:Piperidines; C004998:ferrocene