Co-Al bimetallic hydroxide nanocomposites coating for online in-tube solid-phase microextraction

Boron nitride modified reduced graphene oxide as solid-phase microextraction coating material for the extraction of seven polycyclic aromatic hydrocarbons from water and soil samples

A novel hexagonal boron nitride modified reduced graphene oxide material was synthesized and used as the adsorbent for the solid-phase microextraction of seven polycyclic aromatic hydrocarbons from water and soil samples prior to their detection by gas chromatography-flame ionization detector. Under optimal conditions, the linear response range of the analytes for water sample is 0.25-50 ng/mL with the correlation coefficients (r) ranging between 0.9953 and 0.9996. The linear range for soil sample is 1.0-400 ng/g with r ranging from 0.9959 to 0.9999. On the basis of the signal-to-noise ratio of 3, the limits of detections for the analytes ranged from 0.05 to 0.15 ng/mL for water samples, and from 0.3 to 0.5 ng/g for soil samples. The relative recoveries of the seven polycyclic aromatic hydrocarbons for water and soil samples were in the range of 79.55-120.0 and 78.76-120.8%, respectively. The relative standard deviations for the determination of the analytes in water and soil samples were lower than 11 and 10%, respectively. The method is simple and suitable for the determination of polycyclic aromatic hydrocarbon residues in water and soil samples.

Carbon aerogel as a solid-phase microextraction fiber coating for the extraction and detection of trace tetracycline residues in food by coupling with high-performance liquid chromatography

A direct immersion solid-phase microextraction method for determining tetracyclines (TCs) was developed by coupling with high-performance liquid chromatography. A carbon aerogel (CA) was synthesized as a fiber coating with high extractive properties and a low density of 0.1855 g cm-3via ambient pressure drying and carbonization. The as-synthesized CA exhibited a high specific surface area and a cross-linked structure; it was characterized via scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analysis, etc. The extraction performance for six TCs was investigated, and the main experimental parameters were optimized by the Box-Behnken design. Adsorption kinetics, Langmuir and Freundlich models were used to clarify the extraction mechanism. This method showed wide linear ranges of 1-500 μg L-1, low limits of detection of 0.52-1.05 μg L-1, good repeatability of 1.37-12.47%, and satisfactory inter-fiber reproducibility of 8.51-15.81% relative standard deviation for the detection of six TCs. Moreover, this study provided an interesting insight into the detection of TCs residues in food samples.

In-tube solid-phase microextraction: Current trends and future perspectives

In-tube solid-phase microextraction (IT-SPME) was developed about 24 years ago as an effective sample preparation technique using an open tubular capillary column as an extraction device. IT-SPME is useful for micro-concentration, automated sample cleanup, and rapid online analysis, and can be used to determine the analytes in complex matrices simple sample processing methods such as direct sample injection or filtration. IT-SPME is usually performed in combination with high-performance liquid chromatography using an online column switching technology, in which the entire process from sample preparation to separation to data analysis is automated using the autosampler. Furthermore, IT-SPME minimizes the use of harmful organic solvents and is simple and labor-saving, making it a sustainable and environmentally friendly green analytical technique. Various operating systems and new sorbent materials have been developed to improve its extraction efficiency by, for example, enhancing its sorption capacity and selectivity. In addition, IT-SPME methods have been widely applied in environmental analysis, food analysis and bioanalysis. This review describes the present state of IT-SPME technology and summarizes its current trends and future perspectives, including method development and strategies to improve extraction efficiency.

A green analytical method for the analysis of polycyclic aromatic hydrocarbons in oral fluids from crack smokers

Aim: Develop and validate a method of solid-phase microextraction (SPME) and liquid chromatography to investigate three major polycyclic aromatic hydrocarbons (PAHs) in oral fluid. Results/Methodology: The extraction phase was exposed to 1.5 ml of diluted oral fluid under stirring at 1000 rpm for 60 min, at 70°C. Then, it was immersed in 200 μl of acetonitrile for 10 min at 25°C for desorption of the analytes. Linearity, absolute recovery, and inter- and intra-assay relative standard deviations and relative errors were 50-300 ng.ml^-1, ≥24% and ≤15% for all analytes, respectively. A full factorial design was used to SPME optimization. Discussion/Conclusion: The method is suitable for the exploratory analysis of some PAHs in the oral fluid of crack smokers.

Modulating the selectivity of solid-phase microextraction fibers based on morphological, compositional, and size-depended control of bimetallic oxide nanostructures grown on nickel-titanium alloy substrates

Nickel-titanium oxide nanotubes (NiTiONTs), nanoparticles, and nanopores were in situ grown on NiTi fiber substrates by controlling anodization parameters. The adsorption performance of different bimetallic oxide nanostructures was evaluated using typical aromatic compounds including chlorophenols, phthalic acid esters, ultraviolet filters (UVFs), and polycyclic aromatic hydrocarbons (PAHs) coupled to HPLC-UV. The results clearly indicate that these NiTiO nanostructures show good extraction capability for UVFs and PAHs. The extraction performance of UVFs and PAHs greatly depends on the surface morphologies and sizes of the grown NiTiO nanostructures along with their elemental compositions. Compared with NiTiO nanoparticle and nanopore coatings, the longer well-aligned NiTiONT coating exhibits better extraction capability and selectivity for PAHs than for UVFs. Therefore, the extraction parameters of the NiTi@NiTiONT fiber for PAHs were investigated and optimized. Under optimized conditions, the proposed method was linear in the range 0.05-200 μg L^-1 with correlation coefficients above 0.999. Limits of detection were between 0.008 and 0.124 μg L^-1. Relative standard deviations (RSDs) of the intra-day and the inter-day analyses with the single fiber varied from 4.09 to 6.33%. RSDs for fiber-to-fiber reproducibility of the proposed method with five fibers prepared in different batches were between 5.75 and 7.43%. The applicability of the proposed method was investigated by the enrichment and determination of target PAHs in environmental water samples and relative recoveries of 84.5 ± 6.5 - 116 ± 7.8% were achieved. Notably, the prepared fiber was stable up to 250 times. Graphical abstract.

Synthesis of an organic-inorganic hybrid absorbent for in-tube solid-phase microextraction of bisphenol A

This research is an application of fiber-in-tube solid-phase microextraction followed by high-performance liquid chromatography with UV detection for the extraction and determination of trace amounts of bisphenol A. Nanomagnetic Fe₃ O₄ was formed on the surface of polypropylene porous hollow fibers to increase the surface area and then it was coated with polystyrene. The introduction of polystyrene improves the surface hydrophobicity and is an appropriate extractive phase because it is highly stable in aquatic media. The extraction was carried out in a short capillary packed longitudinally with the fine fibers as the extraction medium. Extraction conditions, including extraction and desorption flow rates, extraction time, pH, and ionic strength of the sample solution, were investigated and optimized. Under optimal conditions, the limit of detection was 0.01 µg/L. This method showed good linearity for bisphenol A in the range of 0.033-1000 µg/L, with the coefficient of determination of 0.9984. The inter- and intraday precisions (RSD%, n = 3) were 7.9 and 6.3%, respectively. Finally, the method was applied to analysis of the analyte in thermal papers, disposable plastic cups, and soft drink bottles.

Solid-phase microextraction using a β-ketoenamine-linked covalent organic framework coating for efficient enrichment of synthetic musks in water samples

Covalent organic frameworks with tunable porous crystallinity and outstanding stability have recently exhibited fascinating pretreatment performance as solid-phase microextraction coatings. In this report, a β-ketoenamine-linked covalent organic framework (TpPa-1) was successfully constructed through a Schiff-base-type reaction between 1,3,5-triformylphloroglucinol (Tp) and para-phenylenediamine (Pa-1). A TpPa-1 coating was then fabricated on a stainless-steel fiber for capturing trace synthetic musks. This TpPa-1 coating exhibited strong interaction with synthetic musks because of its hydrophobicity and π-π affinity. This TpPa-1-based solid-phase microextraction methodology, coupled with gas chromatography-tandem mass spectrometry, provided high enrichment factors (1214-12 487), wide linearity (0.5-1000 ng L-1), low limits of detection (0.04-0.31 ng L-1), and acceptable reproducibility (relative standard deviation, <10%) for nine synthetic musks. Recoveries at three spiked levels in three types of water samples were between 76.2% and 118.7%. These results indicated the promising applicability of the TpPa-1 as a solid-phase microextraction fiber coating for reliably detecting trace concentrations of synthetic musks in the environment.

Recent Applications and Newly Developed Strategies of Solid-Phase Microextraction in Contaminant Analysis: Through the Environment to Humans

The present review aims to describe the recent and most impactful applications in pollutant analysis using solid-phase microextraction (SPME) technology in environmental, food, and bio-clinical analysis. The covered papers were published in the last 5 years (2014–2019) thus providing the reader with information about the current state-of-the-art and the future potential directions of the research in pollutant monitoring using SPME. To this end, we revised the studies focused on the investigation of persistent organic pollutants (POPs), pesticides, and emerging pollutants (EPs) including personal care products (PPCPs), in different environmental, food, and bio-clinical matrices. We especially emphasized the role that SPME is having in contaminant surveys following the path that goes from the environment to humans passing through the food web. Besides, this review covers the last technological developments encompassing the use of novel extraction coatings (e.g., metal-organic frameworks, covalent organic frameworks, PDMS-overcoated fiber), geometries (e.g., Arrow-SPME, multiple monolithic fiber-SPME), approaches (e.g., vacuum and cold fiber SPME), and on-site devices. The applications of SPME hyphenated with ambient mass spectrometry have also been described.

Innovative Configurations of Sample Preparation Techniques Applied in Bioanalytical Chemistry: A Review

Background:

Recently, in all fields of analytical chemistry, increased attention has been paid to extraction procedures and instrumental methods, which are easily scalable and are able to automate in order to improve the “high-throughput” capability.

Introduction:

The main goal of these applications relates to an improvement of the precision in the quantitative analysis, reduction of different sources of errors, decrease the analysis time and, in general, improve the analytical performances. Often these points can be in contrast to each other, not allowing to achieve the expected result but forcing a compromise between the objectives of the method and the analytical performance.

Methods:

In this review, following the evolution of the (micro)extraction procedures and instrument configurations, the recent procedures used in bioanalytical chemistry are critically evaluated. The aim of this paper is providing an overview of the approaches available in order to perform on-line coupling of various extraction techniques with chromatographic methods for the analysis of different compounds in various samples. Furthermore, a comparison between off-line and on-line systems, advantages of on-line systems applied on major extractive techniques and future perspectives are described.

Result:

The extraction methods suitable for on-line coupling covered in this review are: liquid-liquid extraction (LLE), solid phase extraction (SPE), solid phase microextraction (SPME), dispersive liquid- liquid microextraction (DLLME), microextraction by packed sorbent (MEPS), supercritical fluid extraction (SFE) and fabric phase sorptive extraction (FPSE).

Conclusion:

An overview of the micro-extraction techniques mentioned above was provided, making a comparison between them and focusing attention on future perspectives.

Current status and future trends on automated multidimensional separation techniques employing sorbent-based extraction columns

Determination of target analytes present in complex matrices requires a suitable sample preparation approach to efficiently remove the analytes of interest from a medium containing several interferers while at the same time preconcentrating them aiming to improve the output signal detection. Online multidimensional solid-phase separation techniques have been widely used for the analysis of different contaminants in complex matrices such as food, environmental, and biological samples, among others. These online techniques usually consist of two steps performed in two different columns (extraction and analytical column), the first being employed to extract the analytes of interest from the original medium and the latter to separate them from the interferers. The extraction column in multidimensional techniques presents a relevant role since their variations as building material (usually a tube), sorbent material, modes of application, and so on can significantly influence the extraction success. The main features of such columns are subject of constant research aiming improvements directly related to the performance of the separation techniques that utilize multidimensional analysis. The present review highlights the main features of extraction columns online coupled to chromatographic techniques, inclusive for in-tube solid-phase microextraction, online solid phase and turbulent flow, aiming the determination of analytes present at very low concentrations in complex matrices. It will critically describe and discuss some of the most common instrumental set up as well as comments on recent applications of these multidimensional techniques. Besides that, the authors have described some properties and enhancements of the extraction columns that are used as first dimension on these systems, such as type of column material (poly (ether ether ketone), fused silica, stainless steel, and other materials) and the way that the extractive phase is accommodated inside the tubing (filled and open tubular). Practical applications of this approach in fields such as environment, food, and bioanalysis are also presented and discussed.