title: Efforts to improve detection sensitivity for capillary electrophoresis coupled to atmospheric pressure photoionization mass spectrometry.
abstract: Electrospray ionization performs best with volatile buffers. However, generally the best separation performance for capillary electrophoresis (CE) is achieved with non-volatile buffers. Hyphenation of CE with mass spectrometry (MS) utilizing atmospheric pressure photoionization (APPI) enables use of a wider range of separation buffers without compromising detection sensitivity. As APPI is considered to be mass flow sensitive, the use of a larger inner diameter separation capillary (75 microm) allows larger volumes to be injected, without decreased separation performance, thus providing improved sensitivity (approx. a factor of 10), compared to the use of a 25 microm capillary. However, nebulizing gas flow and position of capillary tip in the sprayer have to be carefully optimized to prevent excessive band broadening. Further improvement in sensitivity (approx. a factor of 2) was obtained by decreasing the distance between the sprayer and ionization region, indicating that a specially designed CE/APPI-MS interface for low flow rates will be favourable.
authors.affiliation: Department of Physical and Analytical Chemistry, Analytical Chemistry, Uppsala University, Box 599, SE-751 24 Uppsala, Sweden.
authors.forename: Jakob
authors.initials: J
authors.lastname: Axén
authors.forename: David
authors.initials: D
authors.lastname: Malmström
authors.forename: Bengt-Olof
authors.initials: BO
authors.lastname: Axelsson
authors.forename: Patrik
authors.initials: P
authors.lastname: Petersson
authors.forename: Per J R
authors.initials: PJ
authors.lastname: Sjöberg
mesh_terms: D000420:Albuterol / Q000032:analysis / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D009538:Nicotine / Q000032:analysis / Q000302:isolation & purification; D011342:Procainamide / Q000032:analysis / Q000302:isolation & purification; D012680:Sensitivity and Specificity
chemical_list: D009538:Nicotine; D011342:Procainamide; D000420:Albuterol