title: Investigation of the effects of wall adsorption of the visualization agent on baseline noise characteristics for indirect UV detection in capillary electrophoresis.
abstract: New insights into the effects of the wall adsorption of the visualization agent on baseline noise characteristics in indirect UV detection in capillary electrophoresis were provided. When compared to relatively small, hydrophilic cationic (1-(4-pyridyl)pyridinium chloride hydrochloride) or anionic chromophores (bromide and benzoate), the use of a UV-absorbing long-chain cationic surfactant (benzyldimethylhexadecylammonium chloride) as a probe (visualization agent) for studying baseline noise characteristics as a function of various experimental conditions, such as applied voltage, pH or buffer composition, was found to provide noise data that were very different under certain conditions. For cationic visualization agents that have a strong tendency of adsorbing onto the capillary surfaces due to electrostatic and/or hydrophobic interactions, it appeared that the interplay of both thermal as well as adsorption/desorption events occurring within the capillary is likely responsible for a fluctuation of the visualization agent concentration at the detector.
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
authors.forename: Tom M H
authors.initials: TM
authors.lastname: Choy
authors.forename: Carmen W
authors.initials: CW
authors.lastname: Huie
mesh_terms: D000097:Acetonitriles; D000327:Adsorption; D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods*; D005233:Fatty Alcohols; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D009994:Osmolar Concentration; D000644:Quaternary Ammonium Compounds; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D055672:Static Electricity; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D002021:Buffers; D005233:Fatty Alcohols; D000644:Quaternary Ammonium Compounds; D012997:Solvents; D013501:Surface-Active Agents; C099033:acetonitrile anion; C012817:cetalkonium chloride