title: Automated microcolumn-switching system for drug analysis by direct injection of human plasma.
abstract: This study presents the application of a system that joins the known advantages of capillary liquid chromatography (e.g., higher concentration of the analytes and lower consumption of mobile phase) with those of column-switching using restricted access material (RAM) (sample clean up and extraction) to the analysis of fluoxetine in plasma samples. Automatically, the system loads the biological sample, while a RAM-BSA-C18 column (50 mm x 520 microm) excludes the macromolecules and focuses the analytes; afterwards, a second mobile phase elutes the analytes, in backflush mode, and provides the separation in a C18 analytical column (100 mm x 520 microm). We optimized the procedure for a total analysis time of 25 min. Using this approach the calibration curve shows r=0.998 with a linearity range from 20 to 500 ng ml(-1). Precision, calculated as relative standard deviation (RSD), was<20%. The developed miniaturized system showed to be adequate and attractive, demonstrating a large potential for sample preparation.
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense, 400, Caixa Postal 780, CEP 13566-590, São Carlos, SP, Brazil.
authors.forename: Alvaro J Santos
authors.initials: AJ
authors.lastname: Neto
authors.forename: José C
authors.initials: JC
authors.lastname: Rodrigues
authors.forename: Christian
authors.initials: C
authors.lastname: Fernandes
authors.forename: Guilherme M
authors.initials: GM
authors.lastname: Titato
authors.forename: Claudete
authors.initials: C
authors.lastname: Alves
authors.forename: Fernando M
authors.initials: FM
authors.lastname: Lanças
mesh_terms: D001331:Automation / Q000379:methods; D002853:Chromatography, Liquid / Q000295:instrumentation* / Q000379:methods; D005473:Fluoxetine / Q000097:blood*; D008832:Microchemistry / Q000379:methods; D010949:Plasma / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D005473:Fluoxetine