Exploring New Extractive Phases for In-Tube Solid Phase Microextraction Coupled to Miniaturized Liquid Chromatography

Abstract

In-tube solid-phase microextraction (IT-SPME) coupled on-line to miniaturized liquid chromatography (LC) has emerged as a powerful tool to address a variety of analytical problems. However, in order to expand its applicability, the development of new sorbents that enhance the efficiency and specificity of the extraction is highly desirable. In this respect, the employment of capillary columns coated with sorbents functionalized with nanoparticles (NPs) replacing the loop of the injection valve (in-valve IT-SPME) is one of the most attractive options. In this work, polymers of tetraethyl orthosilicate (TEOS) and trimethoxyethylsilane (MTEOS) modified with SiO2 and TiO2 NPs have been synthetized and used for the extraction of a variety of water pollutants, using both Capillary-LC and Nano-LC. Compounds with different chemical structures and polarities such as the artificial sweetener saccharine, the polycyclic aromatic hydrocarbons (PAHs) naphthalene and fluoranthene, and some phenylurea and organophosphorous herbicides have been used as target analytes. The extraction efficiencies found with the synthetized capillaries have been compared to those obtained with commercially available capillaries coated with polydiphenyl-polydimethylsiloxane (PDMS), nitroterephthalic acid modified polyetilenglicol (FFAP), and polystyrene-divinylbenzene (PS-DVB) phases. The results obtained in this preliminary study showed that, although PS-DVB phase has the strongest affinity for compounds with two or more aromatic rings, the extraction with TEOS-MTEOS coatings modified with NPs is the best option for a majority of the tested compounds. Examples of application are given.

Fluorometer for Screening of Doxorubicin in Perfusate Solution and Tissue with Solid-Phase Microextraction Chemical Biopsy Sampling

“…The fluorescence method is generally more sensitive than other optical detection techniques, such as UV-absorption or Raman spectroscopy. While fluorescence detection has mostly been used in conjunction with the SPME-LC approach for the analysis of aromatic compounds with native fluorescence, − the utilization of post-column photochemically induced derivatization has also enabled its use in the study of nonfluorescent pyrethroid insecticides . In all of these studies, the analyte was first desorbed from the SPME probe, then separated from impurities via LC, and finally measured using a fluorescence detector.…”

Open tubular liquid chromatography: Recent advances and future trends

“…In general, the diversity of OT coatings for extractive purses superates the ones employed in analysis and separation, possibly due to the short length of the extractive columns, which facilitates its preparation. Critical reviews have recently been introduced summarizing the vast diversity of OT coatings for extractive porpuses [133,[137][138][139][140][141]. Table 2 shows some selected examples of diverse coating and its potential to retain analytes in a broad polarity range.…”

Innovations in Extractive Phases for In-Tube Solid-Phase Microextraction Coupled to Miniaturized Liquid Chromatography: A Critical Review

“…A TEOS-MTEOS polymer was doped with TiO 2 NPs using a procedure similar to that described for the SiO 2 -TEOS-MTEOS phase, and used for IT-SPME coupled to both capLC and nanoLC in [55]. In the capLC system, the extraction efficiencies of the TiO 2 NPs-doped phase were compared with those obtained with commercially available columns, namely TRB 35, FFAP, and polystyrene-divinylbenzene (PS-DBV), as well as with those obtained with SiO 2 NPs-reinforced TEOS-MTEOS.…”