title: Hybrid silica monolith for microextraction by packed sorbent to determine drugs from plasma samples by liquid chromatography-tandem mass spectrometry.
abstract: The present study (1) reports on the synthesis of two hybrid silica monoliths functionalized with aminopropyl or cyanopropyl groups by the sol-gel process; (2) evaluates these monoliths as selective stationary phase for microextraction by packed sorbent (MEPS) to determine drugs in plasma samples via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reactions monitoring (MRM) mode; and (3) discusses important factors related to the optimization of MEPS efficiency as well as the carryover effect. The prepared hybrid silica monoliths consisted of a uniform, porous, and continuous silica monolithic network. The structure of the aminopropyl hybrid silica monolith was more compact than the structure of the cyanopropyl hybrid silica monolith. The Fourier-transform infrared spectroscopy (FTIR) spectra of the hybrid silica monoliths displayed readily identifiable peaks, characteristic of the cyanopropyl and aminopropyl groups. Compared with the aminopropyl hybrid silica phase, the cyanopropyl hybrid silica phase exhibited higher binding capacity for most of the target drugs. The developed method afforded adequate linearity at concentrations ranging from the lower limit of quantification (0.05-1.00 ng mL(-1)) to the upper limit of quantification (40-10,500 ng mL(-1)); the coefficients of determination (r(2)) were higher than 0.9955. The precision of the method presented coefficients of variation (CV) lower than 14%; the relative standard error (RSE) of the accuracy ranged from -12% to 14%. The developed method allowed for simultaneous analysis of five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients, which should be valuable for therapeutic drug monitoring purposes.
authors.affiliation: Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14040-901, Brazil.
authors.forename: Israel D
authors.initials: ID
authors.lastname: de Souza
authors.affiliation: Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14040-901, Brazil.
authors.forename: Diego S
authors.initials: DS
authors.lastname: Domingues
authors.affiliation: Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14040-901, Brazil. Electronic address: mariaeqn@ffclrp.usp.br.
authors.forename: Maria E C
authors.initials: MEC
authors.lastname: Queiroz
mesh_terms: D000927:Anticonvulsants / Q000097:blood*; D000928:Antidepressive Agents / Q000097:blood*; D014150:Antipsychotic Agents / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods; D016903:Drug Monitoring; D006801:Humans; D057230:Limit of Detection; D012822:Silicon Dioxide / Q000737:chemistry; D052617:Solid Phase Microextraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000927:Anticonvulsants; D000928:Antidepressive Agents; D014150:Antipsychotic Agents; D012822:Silicon Dioxide
keywords: Drugs; Hybrid silica monolith; Microextraction by packed sorbent; Plasma samples; Schizophrenia