title: On-line reaction monitoring by extractive electrospray ionisation.
abstract: The design and development of a novel extractive electrospray ionisation (EESI) device for on-line reaction monitoring is described. The EESI apparatus uses a secondary, grounded nebuliser to produce an analyte aerosol and a Venturi pump is then used to transfer a sample of the aerosol to an electrospray source where it is ionised. The EESI apparatus was then tested with a variety of small, organic molecules to assess sensitivity, linearity and dynamic range. The performance of the technique will depend on the mass spectrometer used for the experiments; in the configurations used here it has a usable dynamic range of around 3.5 orders of magnitude with a linear range of around 2.5 orders of magnitude and is capable of analysing species present down to low µg/mL with signal-to-noise ratio greater than 2.5. The use of EESI for reaction monitoring was validated using a series of mock reaction mixtures and then used to monitor the base hydrolysis of ethyl salicylate to salicylic acid.
authors.affiliation: LGC, Queens Road, Teddington TW11 0LY, UK. bryan.mccullough@lgc.co.uk
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: McCullough
authors.forename: Tony
authors.initials: T
authors.lastname: Bristow
authors.forename: Gavin
authors.initials: G
authors.lastname: O'Connor
authors.forename: Chris
authors.initials: C
authors.lastname: Hopley
mesh_terms: D000336:Aerosols / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis; D004364:Pharmaceutical Preparations / Q000032:analysis; D012459:Salicylates / Q000032:analysis; D020156:Salicylic Acid / Q000032:analysis; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D000336:Aerosols; D009930:Organic Chemicals; D004364:Pharmaceutical Preparations; D012459:Salicylates; C041835:ethyl salicylate; D020156:Salicylic Acid