Advances in Sample Preparation最新文献

Solid-phase microextraction (SPME) is a simple, efficient, and solvent-free technique. It integrates the steps of traditional liquid-liquid extraction, i.e., sampling, extraction, concentration, derivatization, in a single step. It is easy, combining capability with gas chromatography (GC), liquid chromatography (LC), and mass spectrometry (MS), which makes this method fast, reliable, and sensitive. SPME method is often associated with extraction at elevated temperature, since increasing temperature may positively affect extraction by increasing the analyte volatility, diffusion, and extraction rate. In this work, a dry-herb vaporizer (vaping pen) was used as a sample heating device for direct desorption of volatile analytes into the headspace of the device. The extraction was performed by sorbing analytes from their gas phase in the headspace of the vape onto a SPME fiber followed by desorption in the injection port for GC–MS characterization. Compounds from horseradish, cinnamon, and gasoline-spiked soil samples were analyzed. The samples were also analyzed by conventional headspace SPME-GC–MS. The results from both methods were compared. The methods produce comparable results in terms of extracted compounds and relative area percentages, however, the dry-herb vaporizer had improved sensitivity.

Mr. Bialetti invented Moka in 1933 and it still represents the most common way to prepare coffee at home. The process through which Mokas extract components from the ground coffee is a solid-liquid extraction which occurs at high pressure and temperature. These features are desirable in simple sample treatment strategies, since they allow good extraction efficiencies in a short time. Herein, for the first time, Moka-pot extraction was considered as an alternative processing protocol to extract polar compounds from dietary supplements. The effect of four experimental variables on extraction efficiency was evaluated through a fractional factorial design of experiments applied to a pooled matrix. In particular, solvent pH and its content of organic modifier, heating temperature and sample mass (reflecting the ratio to the amount of solvent which has to be kept fixed due to practical needs) were considered. The performances of the best conditions were then validated by determining recoveries (between 52 and 134 %, except for acetylsalicylic acid) and matrix effects (resulting always negligible or moderate at 100-fold dilution) of a spiked matrix which did not present any of the target analytes. They were finally applied to real samples, allowing to quantify some compounds, including artificial sweeteners, methylxanthines and taurine. Results were then compared with the quantities declared on the labels and those obtained with a Salt-Assisted Liquid-Liquid Extraction (SALLE), previously developed. Interestingly, the two methods were comparable for most compounds, but Moka extraction allowed to quantify taurine, which was not recovered with the SALLE. This promising result encourages further work to extend the use of the simple Moka device to other analytes and further matrices.

Investigating products under stress conditions provides valuable information for assessing stability, biosimilarity, and degradation behaviors during monoclonal antibody (mAb) development. Proper sample preparation is crucial for accurately evaluating the biosimilarity and effects of stress conditions in comparability assessment, where these studies guide biosimilar mAb development steps. Enzymatic and chemical treatments applied during sample preparation of mAbs generally require treatment of samples in temperatures higher than the storage temperatures of antibodies.

In this study, samples of a TNF-α inhibitor IgG1 biosimilar (BIO) and its originator (OR) were treated for 7 days at commonly used temperatures during sample preparation. Alterations in the intact IgG, size variants, charge variants, binding kinetics, and post-translational modifications (PTMs) were investigated with CE-SDS, SE-UPLC, icIEF, SPR, and LC-MS/MS, respectively. Samples treated at 50 °C exhibited significant degradation, while minor differences were observed in samples treated at 37 °C. Monomer and intact IgG levels were decreased to levels below 97 % and 94 %, respectively, after 7 days of thermal treatment at 50 °C for both BIO and OR samples. Similar rates of degradation were observed between the treated biosimilar and originator samples. The percent monomer degradation rate between the biosimilar and the originators was similar at 50 °C (p = 0.32). Thermal treatment increased acidic variant levels in the products of the BIO (23.10 %) and OR (23.16 %). During post-translational modification monitoring, an increase in pyroglutamic acid formation and a decrease in C-terminal lysine were observed after thermal treatments. Acidic variant alterations were associated with asparagine deamidation and N-terminal pyroglutamic acid formation. Post-translational modifications were mainly located at the Fc domain, with methionine oxidation and asparagine deamidation as the main modifications occurring at the Fab domain.

In conclusion, these results revealed that prolonged thermal treatment under elevated temperatures induces molecular alterations, thereby facilitating the degradation of IgG1. In addition, our findings indicate that both BIO and OR lots exhibit similar degradation profiles when subjected to thermal treatments.

Aim of this study stands in the evaluation of a carbon nanotubes-based polymerized high internal phase emulsion composite (CNT/polyHIPE) as sorptive phase in biological sample preparation. A micro-solid-phase extraction procedure (µSPE) was developed for trace fluoroquinolone (FQ) antimicrobials, namely Ciprofloxacin, Levofloxacin, Lomefloxacin, Moxifloxacin, Norfloxacin and Sparfloxacin, in human urine samples. PolyHIPEs modified by incorporation of different concentrations of nanotubes (0.2–0.8 wt %) were one-pot synthesized and applied in the packed-cartridge setting. The sorption affinity for the drugs was investigated in tap water and buffered aqueous solutions, demonstrating the key role of the nanotubes embedded in the polymer. The 0.5 wt % CNT composite was selected to develop a straightforward µSPE procedure directly in raw urine (1 mL sample), followed by HPLC-MS/MS. Targets were retained on the sorbent at near neutral pH and, after an aqueous washing (0.1 % v/v formic acid), eluted in a single-step with 4 % v/v ammonia aqueous solution (15 % v/v acetonitrile), thus combining extraction and clean-up. The method allowed accurate quantification of FQs, as evidenced by the recoveries (74–116 %, n = 3) obtained on blank pooled urine samples spiked with 40, 75, 150 µg L⁻¹, accompanied by good inter-day precision (RSD < 14 %, n = 3). To confirm the applicability of the analytical method, some real-life blind samples were processed as a proof of concept.

Here, we report an optimization of the extraction of crystal violet and congo red dyes from shrimp samples, employing matrix solid phase dispersion and improved multivariate optimization. Three factors were evaluated: (i) adsorbent nature (neutral alumina, silica gel and C₁₈); (ii) eluent strength (dimethylformamide, methanol and acetonitrile); and (iii) sample-adsorbent ratio (1:1; 1:5; and 1:10, m/m). Successful extraction of dyes was achieved using dimethylformamide as eluent, neutral alumina as adsorbent and sample:adsorbent ratio of 1:5 (m/m). Adsorption and kinetic studies suggest strong interaction between dye and adsorbent. Furthermore, employing digital image colorimetric detection, the study observed limit of detection (LOD) ranging between 3.8 to 29.8 µg L ^{− 1} and limit of quantification (LOQ) ranging between 12.3 to 90.3 µg L ^{− 1} with R² > 0.9927 for both dyes, CV and CR, respectively. Notably, recovery was greater than 86 % with a relative standard deviation (RSD) inferior to 7 % (n = 3). These findings indicate the effectiveness of the improved multivariate optimization technique in conjunction with matrix solid-phase dispersion for successful extraction and quantification of dyes from shrimp samples, showing its potential for accurate and sensitive detection in similar analyses. The proposed method was compared with the gold method (UV/Vis spectroscopy) and the statistical treatment showed that the results of both methods are comparable.

Electromembrane extraction (EME) has been developed into an attractive microextraction concept for extraction of pharmaceuticals and related substances from blood and urine. In EME, charged substances are extracted across a liquid membrane (organic) under the influence of an electrical field. Recently, commercial equipment for EME was launched, and this is expected to increase the interest for the technique. EME has also been explored for extraction of peptides, but this is more complicated due to the challenges related to the solvation of peptides in the organic liquid membrane. In this paper, we review the literature on EME of peptides, and we retrospectively look closer into published studies based on our current understanding of the concept. By such, we can explain early observations in more detail, and we can improve our fundamental understanding.

Application of tetramethylammonium hydroxide for the treatment of samples prior to elemental analysis over the last five years is approached in this review article. Characteristics and properties of this reagent are described for a better understanding of the treatment process. Its effect on analyte measurements performed by atomic spectrometry techniques (flame and graphite furnace atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma optical emission spectrometry and, inductively coupled plasma mass spectrometry) is discussed, mainly the possibilities of physical interferences. Ways of using the reagent in sample preparation, such as incubation at room temperature, use of ultrasound energy, microwave energy, among others, will be discussed, in addition to the use of the reagent in speciation and nanoparticles analyses. Tetramethylammonium hydroxide has proven to be a viable alternative in the treatment of samples that can improve the performance of methods based on atomic spectrometry in the determination of elements of great interest to society.

Salt-assisted liquid-liquid extraction (SALLE) and on-column concentration were evaluated to simplify the chromatographic determination of phenolic compounds in beer. Resveratrol, flavonoids (quercetin and kaempferol), and phenolic acids (caffeic, p-coumaric, and trans-ferulic acids) were used as model compounds based on their concentrations reported in craft beers. SALLE with acetonitrile was effective for sample cleanup, with recoveries ranging from 84% to 112%. The on-column concentration was carried out in high performance liquid chromatography by starting the gradient elution with acidified water (sample carrier stream) in a reversed-phase mode. Consequently, the analytes were retained in a narrow band, and highly polar/ionic potentially interfering species were flushed from the column. The effectiveness of the approach was demonstrated by linear correlations between the peak areas and the injected volumes from 10 to 200 µL (r ≥ 0.999), without significant variations in peak width (< 10%) or retention times (< 0.7%), and peak symmetry (tailing factors within the range of 0.8–1.1). For all analytes, a linear response was achieved from 100 to 1000 µg L⁻¹ (r > 0.999), with limits of detection within the range of 9–82 µg L⁻¹. The approach was also effective for on-column concentrations of resveratrol, quercetin, and kaempferol in sequential injection chromatography (SIC), with injected volumes up to 750 µL and linear responses within 100–1000 µg L⁻¹ (r > 0.997). The proposal reduced consumption of organic solvents (with only 770 µL required per determination in SIC) and avoided solid-phase extraction cartridges for analyte preconcentration.

The rising discharge of anthropogenic chemicals into aquatic environments poses a significant threat, necessitating effective monitoring strategies. This study introduces an innovative approach to effect-directed analysis (EDA) by coupling liquid chromatography (LC) with high-performance thin-layer chromatography (HPTLC), utilizing a modified MALDI spotter. The objective is to optimize fractionation parameters for sample application and assess the method's viability in identifying acetylcholinesterase (AChE) inhibitors, specifically malathion, parathion, and chlorfenvinphos.

The optimization process involves controlling sample volume, spot shape, and spot distances on HPTLC plates. Successful application is demonstrated by a miniaturized LC system coupled to the HPTLC plate via spotter, allowing effective separation and identification of AChE inhibitors. The study further explores the method's application to water samples from a river with predominantly agricultural drainage area.

Spiked samples reveal distinct active spots, identified through extraction and subsequent high-resolution mass spectrometry (HRMS) measurements. However, results indicate the absence of AChE inhibitors in non-spiked water samples, affirming the efficacy of the EU ban on most organophosphate pesticides. The usefulness of HPTLC in separation of coeluting substances from HPLC is emphasized, demonstrating its suitability for the effect-directed analysis of complex samples.

This work shows the integration of HPTLC with liquid chromatography for EDA, offering a powerful tool for identifying and monitoring AChE inhibitors in water samples. The approach addresses limitations in current monitoring strategies and provides insights into the presence and impact of chemicals in aquatic ecosystems. The study contributes to ongoing efforts to enhance water quality monitoring, aligning with the principles of the EU Water Framework Directive.