RESUMEN
A new planar sorptive phase based on the simple immobilization of polymeric ionic liquids on paper is proposed. The sorptive phase can develop hydrophobic or mixed-mode (combining hydrophobic and ion exchange) interactions with the target analytes. The polymer is prepared by the Radziszewski reaction, which takes place in aqueous media, and it has been thoroughly characterized by different techniques including infrared spectroscopy, matrix-assisted laser desorption/ionization coupled to high-resolution mass spectrometry and proton nuclear magnetic resonance. Three different strategies aimed to immobilize the polymeric ionic liquid on paper have been evaluated. Among them, simple thermal curing at 120⯰C was selected. The as-prepared paper has been evaluated for the extraction of several non-steroidal anti-inflammatory drugs from urine, the analytes being finally determined by liquid chromatography with tandem mass spectrometry. The method detection limits were 3.8, 7.2, 6.8, 9.4, 15.7, and 5.1⯵g/L for indomethacin, diclofenac, tolmetin, ketoprofen, naproxen, and ibuprofen, respectively. Calibration models were linear (R2â¯>â¯0.9949) up to 1000⯵g/L. The intra-day precision, expressed as relative standard deviation and calculated at three different concentrations levels (limit of quantification, 250⯵g/L, and 1000⯵g/L), varied between 1.1 and 13%. The accuracy, calculated as relative recovery, was in the range from 72 to 95%, thus being considered appropriate. The easiness of polymeric ionic liquid paper synthesis and the multi-sample extraction protocol designed allows the processing of a high number of samples at the same time.
Asunto(s)
Antiinflamatorios no Esteroideos/orina , Imidazoles/química , Líquidos Iónicos/química , Papel , Polímeros/química , Adsorción , Cromatografía Liquida , Humanos , Imidazoles/síntesis química , Líquidos Iónicos/síntesis química , Límite de Detección , Polímeros/síntesis química , Microextracción en Fase Sólida/instrumentación , Microextracción en Fase Sólida/métodos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masas en TándemRESUMEN
This article describes a method for the modification of paper with single-wall carbon nanohorns (SWCNHs) to form stable suprastructures. The SWCNHs form stable dahlia-like aggregates in solution that are then self-assembled into superior structures if the solvent is evaporated. Dipping paper sections into a dispersion of SWCNHs leads to the formation of a thin film that can be used for microextraction purposes. The coated paper can be easily handled with a simple pipette tip, paving the way for disposable extraction units. As a proof of concept, the extraction of antidepressants from urine and their determination by direct infusion mass spectrometry is studied. Limits of detection (LODs) were 10 ng/L for desipramine, amitriptyline, and mianserin, while the precision, expressed as a relative standard deviation, was 7.2%, 7.3%, and 9.8%, respectively.