The new silica-based coated SPME fiber as universal support for the confinement of ionic liquid as an extraction medium

Solid-phase microextraction - a future technique in pharmacology and coating trends

Traditional sample preparation techniques based on liquid-liquid extraction (LLE) or solid-phase extraction (SPE) often suffer from a major error due to the matrix effects caused by significant co-extraction of matrix components. The implementation of a modern extraction technique such as solid-phase microextraction (SPME) was aimed at reducing analysis time and the use of organic solvents, as well as eliminating pre-analytical and analytical errors. Solid-phase microextraction (SPME) is an innovative technique for extracting low molecular weight compounds (less than 1500 Da) from highly complex matrices, including biological matrices. It has a wide range of applications in various types of analysis including pharmaceutical, clinical, metabolomics and proteomics. SPME has a number of advantages over other extraction techniques. Among the most important are low environmental impact, the ability to sample and preconcentrate analytes in one step, simple automation, and the ability to extract multiple analytes simultaneously. It is expected to become, in the future, another method for cell cycle research. Numerous available literature sources prove that solid-phase microextraction can be a future technique in many scientific fields, including pharmaceutical sciences. This paper provides a literature review of trends in SPME coatings and pharmacological applications.

Quinoline Bridging Hyperconjugated Covalent Organic Framework as Solid-Phase Microextraction Coating for Ultrasensitive Determination of Phthalate Esters in Water Samples

Phthalate esters (PAEs) are widely distributed in the environment, and this has caused serious health and safety concerns. Development of rapid and ultrasensitive identification and analysis methods for phthalate esters is urgent and highly desirable. In this work, a novel nitrogen-rich covalent organic framework (N-TTI) derived quinoline bridging covalent organic framework (N-QTTI) was fabricated and used as a solid-phase microextraction (SPME) coating for the ultrasensitive determination of phthalate esters in water samples. The physical and chemical properties of N-QTTI were investigated sufficiently. The N-QTTI-coated fiber demonstrates a superior enrichment performance than either the N-TTI-coated fiber or commercial fibers under the optimized SPME conditions. For the first time, we propose a semi-immersion strategy for the extraction of PAEs from water samples based on N-QTTI-coated SPME fibers. Combined with gas chromatography-mass spectrometry (GC-MS), the developed method N-QTTI-SPME-GC-MS exhibits a wide linear range with a satisfactory linearity (R2 ≥ 0.995). The limits of detection (LOD, S/N = 3) and the limits of quantification (LOQs, S/N = 10) were 0.17-1.70 and 0.57-5.60 ng L-1, respectively. The repeatability of the new method was examined using relative standard deviations (RSDs) between intraday and interday data, which were 0.38-7.98% and 1.22-6.60%, respectively. The spiked recoveries at three levels of 10, 100, and 1000 ng L-1 were in the range of 90.0-106.2% with RSDs of less than 7.48%. The enrichment factors ranged from 291 to 17180. When compared to previously published works, the LODs of the newly established method were improved 5-5400 times, and the enrichment factors were increased by at least 8 times. The absorption mechanism was investigated by X-ray photoelectron spectroscopy and noncovalent interaction force analysis. The technique was successfully employed for detecting PAEs in water samples.

In situ growth of porous organic framework on iron wire for microextraction of polycyclic aromatic hydrocarbons

In this work, a novel spherical metal organic framework (MOF) was first in situ grown on the surface of iron wire (IW), in which IW served as the substrate and metal source for MOF (type NH₂-MIL88) growth without adding additional metal salts in the process, while spherical NH₂-MIL88 provided more active sites for further construction of multifunctional composites. Subsequently, a covalent organic framework (COF) was covalently bonded to the surface of the NH₂-MIL88 to obtain the IW@NH₂-MIL88@COF fibers, which were used for headspace solid-phase microextraction (HS-SPME) of polycyclic aromatic hydrocarbons (PAHs) in milk samples prior to determination by gas chromatography-flame ionization detection (GC-FID). Compared with the fiber prepared by physical coating, the IW@NH₂-MIL88@COF fiber prepared by in situ growth and covalent bonding exhibits better stability and possesses more uniform layer. The extraction mechanism of the IW@NH₂-MIL88@COF fiber for PAHs was discussed, which mainly owed to π-π interactions and hydrophobic interactions. After optimization of the primary extraction conditions, the SPME-GC-FID method was established for five PAHs with a wide linear range (1-200 ng mL^-1), good linearity coefficient (0.9935-0.9987) and low detection limits (0.017-0.028 ng mL^-1). The relative recoveries for PAHs detection in milk samples ranged from 64.69 to 113.97%. This work not only provides new ideas for the in situ growth of other types of MOF, but also provides new methods for the construction of multifunctional composites.

Head-Space SPME for the Analysis of Organophosphorus Insecticides by Novel Silica IL-Based Fibers in Real Samples

This work demonstrates the suitability of a newly developed ionic liquid (IL)-based silica SPME fiber for the determination of seven organophosphorus insecticides in cucumber and grapefruit samples by headspace solid-phase microextraction (HS-SPME) with a gas chromatography−flame ionization detector (FID). The sol-gel method released four different sorbent coatings, which were obtained based on a silica matrix containing ILs immobilized inside its pores. In order to obtain ionogel fibers, the following ionic liquids were utilized: 1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide; Butyltriethyl ammonium bis(trifluoromethylsulfonyl)imide; 1-(2-Methoxyethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-Benzyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The developed fibers were applied for the extraction of seven different insecticides from liquid samples. The most important extraction parameters of HS-SPME coupled with the GC-FID method were optimized with a central composite design. The new SPME fiber demonstrated higher selectivity for extracting the analyzed insecticides compared with commercially available fibers. The limit of detection was in the range of 0.01−0.93 μg L−1, the coefficients of determination were >0.9830, and 4.8−10.1% repeatability of the method was found. Finally, the obtained ionogel fibers were utilized to determine insecticides in fresh cucumber and grapefruit juices.

Preparation of a Novel Solid Phase Microextraction Fiber for Headspace GC-MS Analysis of Hazardous Odorants in Landfill Leachate

The practice of odorant analysis can often be very challenging because odorants are usually composed of a host of volatile organic compounds (VOCs) at low concentrations. Preconcentration with solid phase microextraction (SPME) is a conventional technique for the enrichment of these volatile compounds before analysis by headspace gas chromatography-mass spectrometry (GC-MS). However, commercially available SPME products usually bear the defects of weak mechanical strength and high cost. In this work, novel SPME fibers were prepared by a one-pot synthesis procedure from divinylbenzene (DVB), porous carbon powder (Carbon) and polydimethylsiloxane (PDMS). Factors that influence the extraction efficiency, such as extraction temperature, extraction time, salting effects, pH, stirring rate, desorption temperature and time, were optimized. VOCs in landfills pose a great threat to human health and the environment. The new SPME fibers were successfully applied in the analysis of VOCs from the leachate of a cyanobacteria landfill. Quantification methods of major odor contributors were established, and a good linearity (r > 0.998) was obtained, with detection limits in the range of 0.30–0.50 ng/L. Compared to commercial SPME fibers, the new material has higher extraction efficacy and higher precision. Hence, it is suitable for the determination of hazardous odorants of various sources.