Current Developments and Future Trends in Solid-phase Microextraction Techniques for Pharmaceutical and Biomedical Analyses

Porous material-based sorbent coatings in solid-phase microextraction technique: Recent trends and future perspectives

Miniaturization is a strategy employed in sample preparation that has gained much prominence in recent years due to the need to develop more efficient procedures that consume less solvent and time. The analysis of important families of contaminants, such as pesticides or polycyclic aromatic hydrocarbons ( PAH s), in liquid samples has traditionally been conducted using conventional techniques, such as liquid–liquid extraction ( LLE ) and solid‐phase extraction ( SPE ). Although SPE uses much less amount of solvent than LLE , the volume can still be significant, making both techniques expensive and environment‐unfriendly procedures. The miniaturization of sample preparation processes has led to a new generation of techniques with improved characteristics. Different solid‐phase microextraction ( SPME ) techniques, including fibers, stir bar sorptive extraction ( SBSE ) and thin‐film microextraction ( TFME ), and automated techniques, such as in‐tube solid‐phase microextraction ( IT ‐ SPME ), have allowed the determination of different families of contaminant compounds, including emerging compounds in complex environmental waters, such as seawater, groundwater, or superficial water. The emerging compounds are relatively unknown compounds that are not covered by the existing regulations; they are frequently detected in different environmental compartments in very low concentrations. For this reason, their analysis requires extraction, purification and preconcentration from the matrix and subsequent separation and detection systems that can measure these concentration levels. In this chapter, we review the most recent applications of microextraction techniques based on solid phase coupled to liquid chromatography ( LC ) for the determination of different emerging contaminants in several water environmental matrices.

<i>In Vivo</i> Solid-Phase Microextraction Sampling: A Promising Future

Sample preparation is playing an increasingly important role in sample analysis. The enrichment efficiency of the target and the removal effect of the sample matrix are strongly dependent on the extraction material. Therefore, the development of efficient extraction materials is an important research focus in the field of sample preparation. Various advanced materials such as nanomaterials, mesoporous materials, ionic liquids, aerogels, carbon materials, metal-organic frameworks, and covalent organic frameworks have been introduced to produce a diverse range of extraction materials for sample preparation. Owing to its unique physical and chemical properties, graphene, an excellent carbon nanomaterial, has attracted significant attention in different areas. Due to their unique advantages of large surface area, large π-electrons, excellent adsorption properties, abundant functional groups, and facile chemical modification, graphene-based materials have displayed excellent extraction performance for diverse analytes. Furthermore, graphene-based extraction materials have been applied to pretreat real samples from different fields. This paper provides an overview of the recent advances in graphene sample preparation from 2020 to date. The manuscript covers the use of graphene, graphene oxide, and the related functionalized materials as sorbents, as well as their specific applications in cartridge solid-phase extraction, dispersive solid-phase extraction, magnetic solid-phase extraction, stir bar sorptive extraction, fiber solid-phase microextraction, and in-tube solid-phase microextraction. To prevent the aggregation of graphene, three-dimensional graphene, porous graphene aerogels, graphene-modified silica, and stainless-steel mesh were developed for cartridge solid-phase extraction. Furthermore, some graphene-based extraction materials were used to develop online solid-phase extraction, which allowed for automatic and high-throughput tests. Graphene nanosheets and their hybrid materials with molybdenum disulfide or zinc oxide nanoparticles have been applied to dispersive solid-phase extraction, and several types of contaminants, including metal ions, bisphenol endocrine disruptors, paraben preservatives, and phthalates, could be captured. By combination with magnetic materials using the coprecipitation method or via chemical post-modification, many magnetic graphene extraction materials have been produced for magnetic solid-phase extraction. The introduction of magnetic graphene not only enhanced the extraction efficiency but also simplified the test process, making it highly suitable for complex samples such as food and biological samples. Similar to magnetic solid-phase extraction, stir bar sorptive extraction is a very simple and efficient extraction method that shows good extraction performance for metal ions and organic pollutants from environmental water, medicines in urine, and organic pollutants in cosmetics. In addition to its excellent applicability to solid-phase extraction, graphene delivered satisfactory performance for solid-phase microextraction. Graphene has been used as an extraction coating for the extraction of fibers or tubes by coupling solid-phase microextraction with chromatographic detection, and many kinds of organic pollutants, including polychlorinated biphenyls, phthalates, polycyclic aromatic hydrocarbons, toluene, xylenes, organophosphorus pesticides, phenoxy acid herbicides, and antibiotics, in environmental or biological samples have been successfully determined. The extraction mechanism, including π-π, electrostatic, hydrophobic, hydrophilic, and hydrogen-bonding interactions, is also discussed. Because of the mixed-mode interactions and rich functionalization, graphene-based extraction materials could effectively capture and selectively enrich different types of species. These extraction or microextraction techniques have been coupled with detection methods such as chromatography, mass spectrometry, and atomic absorption spectroscopy and widely used in environmental monitoring, food safety, and biochemical analysis. The future development of graphene in the field of sample pretreatment focuses on the following aspects: 1) functionalization of graphene with specific groups such as affinity groups, chelating groups, and molecularly imprinted sites to achieve unique extraction selectivity; 2) combination of graphene with the advanced materials, including covalent organic frameworks, metal organic frameworks, aerogels, and nanomaterials, thus realizing the complementary advantages between materials, so that the hybrid graphene materials find broad application prospects in sample preparation; 3) combination of electromagnetic materials with graphene to form electromagnetic composites, as well as the use of electromagnetic fields to improve extraction selectivity and efficiency; 4) exploiting the good performance of graphene-based materials to overcome the difficulty encountered in the pretreatment of complex samples; 5) development of more green methods to prepare graphene-based extraction materials or functionalize graphene, in line with the trends in green chemistry; 6) application of more graphene-based materials to online sample preparation for meeting the development trends in the field of analytical chemistry.

A method was developed for the analysis of volatile polar compounds in a water matrix using open cap vials Solid Phase Micro-Extraction (SPME) and Capillary Gas Chromatography (CGC). Both SPME techniques – direct sampling and headspace – were tested. Optimization of experimental conditions – exposure time, desorption time, with headspace SPME in addition the influence of the temperature and ionic strength of the sample solution on compound sorption, and finally GC response – were investigated. The analytes were extracted by directly immersing the 85 μm polyacrylate fiber in the aqueous sample or in the headspace. The linear range of the preconcentration process and the precision were examined. The amount of polar analytes sorbed on the fiber was determined and was found to be concentration dependent; it amounted to 0.014–0.64% in the concentration range of 0.00425–425 ppm studied in aqueous solution for direct sampling SPME and to 0.011–2.76% for solutions of concentration 0.0425–255 ppm for headspace SPME. The limits of determination were ascertained. Headspace SPME was applied to the analysis of real-life samples.

The well-established evaporation rate method for determining the vapour pressure of active ingredients in crop protection down to the order of 10-12 mbar can be supplemented by the new sample preparation technique of Solid Phase MicroExtraction (SPME). With this technique, it is possible to identify evaporating substances by analysis after partitioning into the polymer coating of a thin fibre in the outlet-gas flow of thermogravimetric equipment. The active ingredients fenpropimorph, kresoxim-methyl, metolachlor, clomazone and (Z)-9-dodecenyl acetate were used in this study, which showed that, despite the relatively small amount of collected material, an analytical identification of the evaporating compound by SPME/GC can be successfully achieved. In particular, the experiments have demonstrated a clear correlation between the linearity of the weight loss curve and the evaporation process of a pure compound. In the case of organic compounds that are unstable to heat, the SPME method can also be utilized to show whether, and at what temperatures, decomposition of the sample into fragments of higher volatility occurs. For example, the insecticide dimethoate showed a clear temperature dependence of both evaporation behaviour and in the SPME/GC analysis. © 1998 SCI

Chapter 1 - Sample preparation for liquid chromatography

Solid-phase microextraction and liquid chromatography/mass spectrometry in drug analysis

An approach to solventless sample preparation procedure for pesticides analysis using solid phase microextraction/supercritical fluid extraction technique

The role of microextraction techniques in occupational exposure assessment. A review

Despite the advances in analytical instrumentation, separation, enrichment and sample clean-up procedures continue to be essential analytical steps prior to the determination stage itself. Numerous potential interferents and low concentrations of analytes make a preliminary extraction procedure necessary. The development of new extraction techniques and the improvement of existing techniques using novel extraction materials are the main trends in this research area. Nanomaterials, materials with sizes or features ranging from 1 to 100 nm in one or more dimensions, have drawn extensive attention from scientists in recent years mainly owing to their unique and attractive thermal, mechanical, electronic and biological properties. Their high surface-to-volume ratio, the possibility for surface functionalization and favorable thermal features provide the flexibility needed in a broad range of analytical application. Their properties have been extensively exploited in different extraction techniques, such as solid-phase extraction and microextraction. Nanomaterials can be used as single particles, aggregates, powders or dispersed in a matrix, and their physicochemical properties can be controlled through structural design, incorporation of suitable components or modification of the surfaces. Whereas monofunctional nanomaterials provide a single function, the preparation of core/shell nanoparticles allows different properties to be combined in one material. In the preparation of these multifunctional nanomaterials, various strategies are used to attain a combination of targeting specificity, magnetic properties and analysis capability. The surface modification of nanomaterials by functional molecules, particles or polymers can improve the separation and preconcentration efficiency, analytical selectivity and method reliability. The aim of this chapter is to provide an updated and critical review of the most important features and applications of nanomaterials (metallic, silica and carbon-based) for solid-phase extraction and microextraction techniques. Emphasis will be placed on description of work that has provided interesting results for use in this analytical field.

Solid-phase microextraction (SPME) is a sample preparation technique which utilizes small amounts of an extraction phase for the extraction of target analytes from investigated sample matrices. Its simplicity of use, relatively short sample processing time, and fiber reusability have made SPME an attractive choice for many analytical applications. SPME has been widely applied to the sampling and analysis of environmental, food, aromatic, metallic, forensic, and pharmaceutical samples. Solid phase microextraction is used in horticultural crops, for example, to determine water and soil contaminants (pesticides, alcohols, phenols, amines, herbicides, etc.). SPME is also used in the food industry to separate biologically active substances in food products for various purposes, for example, disease prevention, determining the smell of food products, and analyzing tastes. SPME has been applied to forensic analysis to determine the alcohol concentration in blood and that of sugar in urine. This method has also been widely used in pharmaceutical analysis. It is a solvent-free sample preparation technique that integrates sampling, isolation, and concentration. This review focuses on recent work on the use of SPME techniques in the analysis of food and horticultural crops.

A headspace solid-phase microextraction (SPME) method was developed for the determination of secondary compounds from Brazilian sugar cane spirits, or cachaça, by GC-FID. An SPME holder with an 85 microm polyacrylate coating was utilized. The novel method is compared with an optimized method: liquid-liquid extraction (LLE). Both methods showed good linearity, but the repeatability for analyses done with the SPME technique (%RSD = 1.8-3.9) was better than for those done with LLE (%RSD = 10.3-11.7). The concentrations of the analytes obtained in the analysis of 12 cachaça samples with the SPME technique were higher than those obtained with LLE. In the SPME method the extraction wastes are smaller. Cachaça samples were qualitatively analyzed for GC-MS.

Analysis of phenolic acids as chloroformate derivatives using solid phase microextraction–gas chromatography

Devido a complexidade dos efeitos fisiológicos nos estádios de maturação de frutas, caracterizar os compostos voláteis auxilia decifrar as alterações de cor, aroma, firmeza, sabor e textura. A microextração em fase sólida (SPME) pode evitar o aquecimento e impedir a degradação de compostos aromáticos, e, portanto, tem sido amplamente utilizada para a extração e enriquecimento de componentes aromáticos, incluindo os de frutas. Neste contexto, o objetivo deste trabalho foi verificar os compostos voláteis durante o processo de amadurecimento da carambola (Averrhoa carambola) e da seriguela (Spondias purpúrea L.) utilizando a técnica de microextração em fase sólida (SPME) acoplada à cromatografia gasosa-espectrometria de massa (GC-MS). Foi possível, por meio da técnica SPME/CG-MS, identificar a composição volátil da carambola e da seriguela em diferentes estádios de maturidade. Em ambos os frutos foram observados compostos que podem ser utilizados como marcadores do estádio de maturação. O aroma da carambola foi constituído, principalmente, por ésteres e o da seriguela, majoritariamente por aldeídos e ésteres.