Advances in Sample Preparation最新文献

The choice of the extraction material is a critical step in solid-phase microextraction (SPME), especially the extraction of analytes which strongly differ in their polarity is challenging. This study is intended to give first insights into the headspace extraction of analytes with large differences in polarity by using a novel hydrophilic-lipophilic-balanced (HLB) SPME material with different particle sizes (5 µm, 5 + 30 µm, and 30 µm) in classical SPME, as well as SPME arrow format. The obtained results were compared to conventional and already established divinylbenzene carbon wide-range polydimethylsiloxane (DVB-CWR-PDMS) and PDMS SPME arrow fibers. The chosen model analytes toluene, indole, phenol, anisole, o-xylene, naphthalene, 2-heptanone, n-dodecane, and lindane are assigned to different substance classes with K_aw values ranging from -5.0–2.5 and K_ow values from 1.5 to 7.5. The highest amount of the analytes was extracted by the HLB 5 + 30 µm arrow and the HLB 5 µm arrow, whereas the HLB SPME with a six times smaller phase volume compared to an SPME arrow, performed almost as well as the DVB-CWR-PDMS arrow. The 8-point calibration with the 5 + 30 µm HLB SPME arrow in the range of 5–70 µg L⁻¹ of the analytes showed good linearity with R² values ranging from 0.9765 to 0.9982, MDLs from 0.9 to 6.2 µg L⁻¹ and RSDs from 2 to 31 %. For all of the observed analytes, the HLB material performed better than the conventional extraction materials and has great potential to replace the conventional extraction materials in many applications.

Chlorophylls and carotenoids are indicators of water quality. A new method based on in-tube solid-phase microextraction (IT-SPME) coupled on-line to nano-liquid chromatography with diode array detection (NanoLC-DAD) was developed. This paper aims to provide selectivity and sensitivity with a short analysis time of about 10 min and low residues of friendly solvents, 5 µL/run of ethanol:water 95:5 and 250 µL of ethanol for dissolving the pigments retained in a nylon filter (0.45 µm, 13 mm) from 30 mL of water. IT-SPME capillary was a fused silica capillary (10 cm length x 75 µm internal diameter, i.d.) with a coating of tetraethyl orthosilicato (TEOS), triethoximethylsilane (MTEOS) doped with SiO₂ nanoparticles (NPs) and an analytical column Zorbax 300SB-C₁₈ (50 mm x 75 µm i.d., 3.5 µm particle size) was used. The recovery obtained to chlorophyll a, chlorophyll b and β-carotene were 93 ± 8 %, 92 ± 7 % and 94 ± 4 %, respectively. The method shows good linearity in the range up to 300 µg L⁻¹ for chlorophyll a and β-carotene and up to 600 µg L⁻¹ for chlorophyll b. The achieved limits of detection (LODs) in samples were 0.1 µg L⁻¹ to chlorophyll a and β-carotene, and 0.2 µg L⁻¹ to chlorophyll b. Values of relative standard deviations (RSD) expressed in% between 2 and 3 were obtained. Pigments were successfully determined with a short analysis time and minimal residues in real water samples.

An overview of the actual state-of-the-art sample treatment procedures for trace and ultra-trace determination of neonicotinoids (NQs) in environmental, food and biological samples is presented. Analytical procedures for NQs, sometimes together with their metabolites/by-products, and NQ-related new generation pesticides have been considered, focusing on sample preparation, which is essential in most cases due to both the complexity of the matrices and low concentrations of residual analytes. Different strategies have been practised for analytes extraction/preconcentration/cleanup, entailing various techniques as solid-liquid extraction (SLE), liquid-liquid extraction (LLE), offline and online solid-phase extraction (SPE), dispersive SPE (d-SPE), magnetic SPE (MSPE), solid-phase microextraction (SPME) and the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach. New solid phases, including inorganic and carbon-based materials, have been prepared, also starting from “green” precursors, and successfully employed in the sample treatment step before hyphenated liquid chromatography or direct electrochemical detection. As well, new environmentally friendly solvents have been evaluated for LLE. The most recent studies (2022-present), around 50 papers, have been reviewed by matrix type, briefly described and commented concerning extraction efficiency, matrix effect, sensitivity, ease of application and sample throughput. Advantages and drawbacks were highlighted, as well as new achievements paving the way for further improvements.

An analytical method combining fatty acid-emulsification liquid-liquid microextraction (FA-ELLME) with solidification of floating drops (SFD) and droplet digital image colorimetry (DDIC) was developed for the analysis of rhodamine B (RhB) in food and beverage samples. This work applied an emulsified amphiphilic fatty acid as an extracting solvent and a freezing procedure for extracting phase separation. A 7 mL sample volume adjusted to pH 5 was extracted with a drop of 35 μL of octanoic acid (0.5%v/v). The emulsification was initiated by shaking for 10 s followed by centrifugation for 5 min. The floating drops containing RhB were solidified in an ice bath, separated from the solution, defrosted, and dropped on the paper platform for DDIC analysis. The limit of detection (LOD) and limit of quantification (LOQ) were 1.8 μg L⁻¹ and 6.0 μg L⁻¹, respectively. The linear range was 10 - 40 μg L⁻¹ (R² = 0.997). The method was applied to determine RhB in beverage, candy, jelly, and chili sauce samples. The relative recovery percentages (RR%) between 73% and 113% were achieved.

The application of deep eutectic solvents (DESs) as green solvents in analytical chemistry has attracted increasing attention. The present study presents a simple, eco-friendly, and cost-effective approach for the extraction of selenium (Se) in food samples. The extraction method utilised alcohol-based DES and inductively coupled plasma optical emission spectrometry (ICP-OES) to determine total Se. Factors affecting the extraction procedure were optimised using the design of experiments. Using the optimal conditions, the limits of detection (LOD) and quantification (LOQ) and linearity of the developed method were 0.0011 µg Se/g, 0.0037 µg Se/g and 0.004–0.20 µg Se/g, respectively. The precision expressed as relative standard deviations (RSDs) was less than 10 %. The accuracy of the method was investigated using certified reference materials (IRMM 804 Rice Flour and NIST SRM 1567b wheat flour), and the results were in close agreement with the certified values (0.038 µg/g and 1.14 µg/g) with percentage recoveries ranging from 89.5 to 106 %. The interday ( %RSD) and Intraday ( %RSD) were 2.8–5.4 % and 4.3–5.9 %, respectively. The greenness of the method was assessed using NEMI, AES, and AGREE metrics tools. When comparing all these tools, they all qualified the proposed method as green.

Vacuum-assisted headspace high capacity solid-phase microextraction (Vac-HS-HC-SPME) coupled with gas chromatography–mass spectrometry (GC–MS) was used to compare the volatile compounds that make up the volatile and semi-volatile components of five psilocybin mushrooms (Psilocybe cubensis), as well as three non-psilocybin mushroom species. Using an untargeted analysis, common volatiles detected consisted of acids, alcohols, aldehydes, ketones, and hydrocarbons. The initial comparison of Vac-HS-HC-SPME and HS-HC-SPME conditions showed 2 times increase in compound response as well as the detection of 8 additional compounds undetected by HS-HC-SPME. Compounds unique to psilocybin mushrooms were 2-methylbutanal, valeraldehyde, benzaldehyde, 3-octen-2-one, 2-methyl-dodecane, and 2‑butyl‑2-octenal. Compounds unique to non-psilocybin mushrooms were 2-methyl-pyrazine, 2,3-butanediol, butyric acid, butyrolactone, benzyl alcohol, 2-pyrrolidinone, and estragole. The commonly shared compound, 1-octen-3-ol, was shown to have a higher compound response among the psilocybin mushroom species.

In recent years, electromembrane microextraction techniques have been used widely for the analysis of chromium species (trivalent and hexavalent chromium) in different environmental matrices. It is based on the electrokinetic migration across a membrane under the effect of an external electrical field between two aqueous phases. Trace analysis in complex matrices usually requires an effective sample preparation step to isolate, extract, and enrich the target analytes. Due to its distinctive qualities, including a high degree of enrichment factors, clean-up, and conformity with green chemistry principles, electromembrane microextraction techniques are among the methods for extracting chromium that have gained much attention in recent years. These techniques could be classified into two groups; electromembrane extraction (EME) which is based on using hydrophobic compounds (e.g., a few microliters of organic solvents) to separate the two aqueous solutions (donor and acceptor solutions), and gel electromembrane microextraction (G-EME) which is based on using a membrane made of biopolymers. In this review, the most recent advancements in EME and G-EME technologies for the extraction of chromium species in environmental samples in the last five years were summarized. Furthermore, the performance of the systems is evaluated in terms of their precision and accuracy, detection limits, and merits and drawbacks. Finally, future perspectives on these techniques were discussed.

Green Analytical Chemistry (GAC) principles have influenced the development of analytical methods with minimal sample handling and operations, in contrast to conventional techniques, which are often laborious and time-consuming. Since the introduction of microextraction techniques in the 1990s, various approaches, configurations, and sorptive phases have been proposed to replace Solid Phase Extraction (SPE) and Liquid-Liquid Extraction (LLE), covering a wide range of matrices and analytes, focused on chromatography and mass spectrometry instrumentation. The main features of microextraction techniques are simplicity, low solvent consumption, and minimum residue generation. The demand for fast results and the large number of samples, along with advances in analytical instrumentation, have led to the coupling of microextraction techniques with automation and/or the development of technologies for multiple extractions at the same time, known as parallel extractions. As a result of its popularity in medical and pharmaceutical sciences, the 96-well plate has been successfully adapted for Solid Phase Microextraction (SPME) and Liquid Phase Microextraction (LPME), significantly reducing the time required to process a large number of samples. This review presents some of the basic principles of microextraction techniques, and it contextualizes and compares analytical methods published in the period of 2018 to early 2023 in the microextraction context for high-throughput analyses.

Glycosylation, a prevalent post-translational modification, plays a significant role in diverse biological processes and exhibits associations with various diseases, including cancer. Among the different types of glycosylation, N-glycosylation is particularly prominent. Glycosylation analysis also plays a crucial role in understanding the efficacy of protein biopharmaceuticals, as the majority of these drugs are glycoproteins. The precise detection and characterization of N-glycosylation require a series of enrichment steps. On the other hand, peptide fragmentation methods constitute a crucial step in reducing sample complexity. Moreover, enrichment strategies coupled with mass spectrometry are essential for the analysis and identification of N-glycopeptides. This research aims to enhance the detection methods for N-glycopeptides and N-glycoproteins by employing strategies that involve peptide fractionation and glycopeptide enrichment. This study targeted to assess and compare the efficacy of an integration method and a direct enrichment approach in terms of identifying glycopeptides from the glycoproteome of human plasma. The results demonstrate that the integration method detects 212 N-glycopeptides and 88 N-glycoproteins, while Cotton-HILIC direct enrichment detects 88 N-glycopeptides and 41 N-glycoproteins. In conclusion, the employment of Cotton-HILIC enrichment with high pH fractionation exhibits greater qualitative abilities in characterizing the structures and functions of glycopeptides.