title: In-capillary preconcentration of pirimicarb and carbendazim with a monolithic polymeric sorbent prior to separation by CZE.
abstract: CZE was assayed for the separation of carbamate pesticides susceptible to protonation (Pirimicarb, Carbendazim). Different electrophoretic media with high organic contents were explored, adequate separation and resolution being achieved when a BGE based on ACN with acetic acid in the presence of SDS as an ionic additive was used. With a view to increasing the sensitivity of the method, an in-capillary SPE step prior to the electrophoretic separation was developed. We employed a monolithic polymer formed in situ within the capillary as a medium for analyte retention. The synthesized monolithic bed exhibited high porosity and allowed samples to be loaded at flow rates of about 65 microL/min by applying a pressure of 12 bar. A 5-cm length of monolithic sorbent was used to preconcentrate the target analytes from aqueous samples. The analytes retained were eluted from the polymeric phase directly in the separation capillary with the same electrophoretic medium used for their further separation by CZE. For a 15-min preconcentration time, the in-line SPE-CZE approach proposed here permitted the determination of these pesticides in drinking water at a concentration level of 0.1 microg/L, as demanded by current EU legislation.
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias Químicas, Universidad de Salamanca, Salamanca, Spain. erg@usal.es
authors.forename: Encarnación
authors.initials: E
authors.lastname: Rodríguez-Gonzalo
authors.forename: Javier
authors.initials: J
authors.lastname: Domínguez-Alvarez
authors.forename: Luis
authors.initials: L
authors.lastname: Ruano-Miguel
authors.forename: Rita
authors.initials: R
authors.lastname: Carabias-Martínez
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D001562:Benzimidazoles / Q000032:analysis* / Q000737:chemistry; D002219:Carbamates / Q000032:analysis* / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D004962:Estranes / Q000737:chemistry; D009570:Nitriles / Q000737:chemistry; D010573:Pesticide Residues / Q000032:analysis* / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011743:Pyrimidines / Q000032:analysis* / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*; D014867:Water / Q000737:chemistry; D014881:Water Supply / Q000032:analysis
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D004962:Estranes; D009570:Nitriles; D010573:Pesticide Residues; D011108:Polymers; D011743:Pyrimidines; D014867:Water; C084683:3-hydroxy-5-estrane-17-carbonitrile; C011994:pirimicarb; D012967:Sodium Dodecyl Sulfate; C006698:carbendazim; D019342:Acetic Acid