Solid-phase extraction (SPE), solid-phase microextraction (SPME) using carbowax/divinylbenzen fiber, and stir bar sorptive extraction (SBSE) followed by solvent back extraction have been used for the extraction of free fatty acids (caproic, caprylic, pelargonic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, and linolenic acids) from beer. Subsequent gas chromatographic analyses with flame ionization detection were used for the determination of these compounds. Medium-chain fatty acids (caproic-lauric acid) were determined as free acids, and long-chain fatty acids (myristic-linolenic acids) were determined as methyl esters after methylation by BF(3)-methanol 14%. Linearity, recovery, and repeatability of all methods have been determined and compared with the SPE method used as a reference (SPME method was used only for medium-chain fatty acid determination). All three procedures provide similar working parameters characterized by high repeatability (2.3-16.3%) and good linearity (correlation coefficient ranging from 0.9919 to 0.9999). Results of beer analyses obtained by using these three methods were highly correlated. Although all methods provide compatible alternatives, for medium-chain fatty acid analysis SPME may be a more appropriate technique due to its operational simplicity, repeatability, and low cost.

• MeSH
• chromatografie plynová MeSH
• extrakce na pevné fázi přístrojové vybavení   metody   MeSH
• mastné kyseliny analýza   MeSH
• mikroextrakce na pevné fázi přístrojové vybavení   metody   MeSH
• pivo analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• mastné kyseliny MeSH

Solid phase extraction is routinely used in many different areas of analytical chemistry. Some of the main fields are environmental, biological, and food chemistry, where cleaning and pre-concentration of the sample are important steps in the analytical protocol. Molecularly imprinted polymers (MIPs) have attracted attention because they show promise as compound-selective or group-selective media. The application of these synthetic polymers as sorbents allows not only pre-concentration and cleaning of the sample but also selective extraction of the target analyte, which is important, particularly when the sample is complex and impurities can interfere with quantification. This review surveys the selectivity of MIPs in solid phase extraction of various kinds of analytes.

• MeSH
• extrakce na pevné fázi metody   MeSH
• molekulový imprinting * MeSH
• polymery chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• polymery MeSH

The sample preparation including labeling and clean-up represents a key analytical step in the analysis of oligosaccharides and glycans by either chromatographic or electrophoretic separation methods. Although the majority of labeling has been performed by neutral and/or negatively charged tags, the introduction of a positive charge into the saccharide molecule can significantly improve the analysis, especially with mass spectrometry detection. In this work, we present the evaluation of five solid-phase extraction sorbents differing in extraction chemistry for the clean-up and concentration of positively labeled maltooligosaccharides from the reaction mixtures. Maltooligosaccharides containing four to seven glucose units were labeled by cationic tags (2-aminoethyl)trimethylammonium chloride and (carboxymethyl)trimethylammonium chloride hydrazide and the extraction conditions were optimized followed by electrophoretic analysis with conductivity detection. The effects of the solid-phase extraction sorbent chemistry, extraction conditions, and sample composition are discussed. All tested sorbents were capable of cleaning up maltooligosaccharides from the reaction mixtures to some extent after optimization of the solid-phase extraction procedure (51.9%-98.9% recovery). The best-rated amide-based sorbent was used to process the sample of N-linked glycans enzymatically released from ribonuclease B.

• Klíčová slova
• capillary electrophoresis, cationic labeling, glycans, oligosaccharides, solid-phase extraction,
• MeSH
• elektroforéza kapilární metody   MeSH
• extrakce na pevné fázi MeSH
• hmotnostní spektrometrie MeSH
• oligosacharidy * analýza   MeSH
• polysacharidy * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• oligosacharidy * MeSH
• polysacharidy * MeSH

Glycopeptide enrichment is a crucial step in glycoproteomic analysis, often achieved through solid-phase extraction (SPE) on polar stationary phases in hydrophilic interaction liquid chromatography (HILIC). This study explores the potential of polyaniline (PANI)-coated silica gel for enriching human immunoglobulin G (IgG). Experimental conditions were varied to assess their impact on glycopeptide enrichment efficiency, comparing PANI-cotton wool SPE with conventional cotton wool as SPE sorbents. Two formic acid concentrations (0.1% and 1%) in elution solvent were tested, revealing that higher concentrations led to earlier elution of studied glycopeptides, especially for sialylated glycopeptides. Substituting formic acid with acetic acid increased the interaction of neutral glycopeptides with the PANI-modified sorbent, while sialylated glycopeptides showed no significant change in enrichment efficiency. Acetonitrile concentration in the elution solvent (5%, 10%, and 20%) affected the enrichment efficiency with most glycopeptides eluting at the lowest acetonitrile concentration. The acetonitrile concentration in conditioning and washing solutions (65%, 75%, and 85%) played a crucial role; at 65% acetonitrile, glycopeptides were least retained on the stationary phase, and neutral glycopeptides were even detected in the flow-through fraction. This study shows the potential of in-house-prepared PANI-modified sorbents for SPE-HILIC glycopeptide enrichment, highlighting the crucial role of tuning experimental conditions in sample preparation to enhance enrichment efficiency and selectivity.

• Klíčová slova
• Glycopeptide enrichment, HILIC, Immunoglobulin G, Polyaniline, Solid-phase extraction,
• MeSH
• acetonitrily MeSH
• aniliny * MeSH
• chromatografie kapalinová metody   MeSH
• extrakce na pevné fázi * metody   MeSH
• formiáty * MeSH
• glykopeptidy * chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• lidé MeSH
• rozpouštědla MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetonitrily MeSH
• aniliny * MeSH
• formiáty * MeSH
• formic acid MeSH Prohlížeč
• glykopeptidy * MeSH
• polyaniline MeSH Prohlížeč
• rozpouštědla MeSH

The aim of the work was to synthesize a molecularly imprinted material for the selective solid-phase extraction (SPE) of β-N-methylamino-L-alanine (L-2-amino-3-methylpropionic acid; BMAA) from cyanobacterial extracts. BMAA and its structural analogs that can be used as template are small, polar and hydrophilic molecules. These molecules are poorly soluble in organic solvents that are commonly used for the synthesis of acrylic-based polymers. Therefore, a sol gel approach was chosen to carry out the synthesis and the resulting sorbents were evaluated with different extraction procedures in order to determine their ability to selectively retain BMAA. The presence of imprinted cavities in the sorbent was demonstrated by comparing elution profiles obtained by using molecularly imprinted silica (MIS) and non-imprinted silica (NIS) as a control. The molecularly imprinted solid-phase extraction (MISPE) procedure was first developed in a pure medium (acetonitrile) and further optimized for the treatment of cyanobacterial samples. It was characterized by high elution recoveries (89% and 77% respectively in pure and in real media).The repeatability of the extraction procedure in pure medium, in real medium and the reproducibility of MIS synthesis all expressed as RSD values of extraction recovery of BMAA were equal to 3%, 12% and 5%, respectively. A MIS capacity of 0.34 µmol/g was measured. The matrix effects, which affected the quantification of BMAA when employing a mixed mode sorbent, were completely removed by adding a clean-up step of the mixed-mode sorbent extract on the MIS.

• Klíčová slova
• Molecularly imprinted silica, Solid phase extraction, Sol–gel, β-N-methylamino-l-alanine,
• MeSH
• adsorpce MeSH
• aminokyseliny diaminové analýza   chemie   MeSH
• extrakce na pevné fázi MeSH
• molekulový imprinting MeSH
• Oscillatoria chemie   MeSH
• oxid křemičitý chemie   MeSH
• toxiny kmene Cyanobacteria MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminokyseliny diaminové MeSH
• beta-N-methylamino-L-alanine MeSH Prohlížeč
• oxid křemičitý MeSH
• toxiny kmene Cyanobacteria MeSH

Porous polymer monoliths have been used to develop an online solid-phase extraction with liquid chromatography method for determination of dopamine in urine as well as for a continuous monitoring of dopamine in flowing system. A polymerization mixture containing 4-vinylphenylboronic acid monomer has been used to prepare a trapping column based on specific ring formation reaction with dopamine cis-diol functionality. Additionally, a monolithic stationary phase with zwitterion functionality has been used to prepare capillary column for the separation of dopamine. Experimental conditions including molarity, pH, and flow rate of the loading buffer together with a valve switching time have been optimized to provide the highest recovery for dopamine. Experimental setup has been used to determine dopamine in a urine. By using both calibration curve and standard addition method, the dopamine level was determined to be 1.19 and 1.28 mg/L, respectively. Further, we have used experimental design to optimize coupling of two extraction monolithic loops to separation capillary column with monolithic phase for a comprehensive monitoring of dopamine. After multivariate analysis, sample loading flow-rate and a flow-rate of flushing buffer were selected as the most significant variables. Optimized experimental setup was applied to continuously monitor dopamine degradation.

• Klíčová slova
• Design of experiments, Dopamine, Monomers, Polymer monoliths, Solid-phase extraction,
• MeSH
• dopamin moč   MeSH
• extrakce na pevné fázi * MeSH
• lidé MeSH
• polymerizace MeSH
• polymery MeSH
• vysokoúčinná kapalinová chromatografie * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dopamin MeSH
• polymery MeSH

UV-benzotriazoles have been identified as water micropollutants that cause serious problems for human health and the environment. Their low concentration in water bodies complicates their detection by direct water analysis, slowing the corrective actions to avoid bioaccumulation. In this regard, the use of graphene-based materials with a high affinity for non-polar molecules has been demonstrated to be a potential tool for the optimal separation and concentration of this type of molecules in solid phase extraction (SPE) processes. This work evaluates the potential of novel reduced graphene oxide aerogels (rGO) as extractants of mixtures of three UV-benzotriazoles in water at low concentrations. These rGO aerogels incorporate graphenic domains into a tough structure of polymeric chains by adding graphene oxide during the synthesis of resorcinol-formaldehyde gels. Aerogels with a different content and ordering of graphenic domains were obtained and characterized using Raman, XRD, SEM and nitrogen adsorption isotherms (-196 °C). The rGO aerogels that performed better as solid phase extractants were those containing 60% rGO. Aerogels with lower rGO contents (40%) required a high-temperature (2000 °C) treatment to render competitive results. The SPE methodology using selected rGO aerogels was optimized by varying the elution solvent, elution time and volume. The best performances, i.e., recoveries of 80-100% and enrichment factors of 12.5-50, were accomplished when using 0.8 mL of tetrahydrofuran (THF) as an elution solvent. As a result, a fast (10 min) and simple extraction method of UV-benzotriazoles in water was attained, achieving a detection limit of 1 ng mL-1. Selected aerogels were finally tested for the SPE of spiked samples of river waters, showing a similar performance to that observed with synthetic mixtures.

• Klíčová slova
• SPE, UV-benzotriazoles, reduced graphene oxide aerogels, solid phase extraction,
• Publikační typ
• časopisecké články MeSH

The efficiency of solid phase extraction (SPE) of DNA on polymer particles is limited by the features of the applied solid support, such as size, hydrophilicity, and functionality and their application in SPE also requires additional steps and compounds to finally obtain sufficient amount of high-quality DNA. The present study describes a preparation of sub-micrometer monodisperse poly(methacrylic acid-co-ethylene dimethacrylate) (PME) particles by precipitation polymerization. The effect of the ethylene dimethacrylate (EDMA) crosslinker concentration on morphology and particle size, which varied from 730 to 900 nm, was investigated. The particles with 5 and 15 wt% EDMA were selected for a study of SPE of plasmid DNA under various adsorption and elution conditions, followed by the enzymatic restriction of isolated DNA to verify a quality the nucleic acid. The particles with 15 wt% EDMA were suitable for the SPE because they retained better colloidal stability during the adsorption without additional induction of DNA conformational change. The quality of isolated DNA was finally verified by enzymatic restriction by restriction endonuclease EcoRI. Moreover, the developed method using PME particles was successfully utilized for DNA isolation from Escherichia coli lysate.

• Klíčová slova
• DNA, EcoRI, Enzymatic restriction, Microparticles, Poly(methacrylic acid-co-ethylene dimethacrylate), Solid phase extraction,
• MeSH
• DNA bakterií chemie   izolace a purifikace   MeSH
• DNA chemie   izolace a purifikace   MeSH
• extrakce na pevné fázi * metody   MeSH
• hydrofobní a hydrofilní interakce MeSH
• koncentrace vodíkových iontů MeSH
• polymery chemie   MeSH
• polymethylmethakrylát chemie   MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA bakterií MeSH
• DNA MeSH
• poly(MAA-co-EDMA) MeSH Prohlížeč
• polymery MeSH
• polymethylmethakrylát MeSH

Reaching trace amounts of mycotoxin contamination requires sensitive and selective analytical tools for their determination. Improving the selectivity of sample pretreatment steps covering new and modern extraction techniques is one way to achieve it. Molecularly imprinted polymers as selective sorbent for extraction undoubtedly meet these criteria. The presented work is focused on the hyphenation of on-line molecularly imprinted solid-phase extraction with a chromatography system using a column-switching approach. Making a critical comparison with a simultaneously developed off-line extraction procedure, evaluation of pros and cons of each method, and determining the reliability of both methods on a real sample analysis were carried out. Both high-performance liquid chromatography methods, using off-line extraction on molecularly imprinted polymer and an on-line column-switching approach, were validated, and the validation results were compared against each other. Although automation leads to significant time savings, fewer human errors, and required no handling of toxic solvents, it reached worse detection limits (15 versus 6 μg/L), worse recovery values (68.3-123.5 versus 81.2-109.9%), and worse efficiency throughout the entire clean-up process in comparison with the off-line extraction method. The difficulties encountered, the compromises made during the optimization of on-line coupling and their critical evaluation are presented in detail.

• Klíčová slova
• column-switching chromatography, molecularly imprinted polymers, mycotoxin, on-line solid-phase extraction, patulin,
• MeSH
• extrakce na pevné fázi * MeSH
• molekulový imprinting * MeSH
• patulin izolace a purifikace   MeSH
• polymery MeSH
• reprodukovatelnost výsledků MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• patulin MeSH
• polymery MeSH

The sample preparation step is pivotal in glycoproteomic analysis. An effective approach in glycoprotein sample preparation involves enriching glycopeptides by solid-phase extraction (SPE) using polar stationary phases in hydrophilic interaction liquid chromatography (HILIC) mode. The aim of this work is to show how different experimental conditions influence the enrichment efficiency of glycopeptides from human immunoglobulin G (IgG) on an aminopropyl-modified SPE column. Different compositions of the elution solvent (acetonitrile, methanol, and isopropanol), along with varying concentrations of elution solvent acidifiers (formic and acetic acid), and different concentrations of acetonitrile for the conditioning and washing solvents (65%, 75%, and 85% acetonitrile) were tested to observe their effects on the glycopeptide enrichment process. Isopropanol proved less effective in enriching glycopeptides, while acetonitrile was the most efficient, with methanol in between. Higher formic acid concentrations in the elution solvent weakened the ionic interactions, particularly with sialylated glycopeptides. Substituting formic acid with acetic acid led to earlier elution of more glycopeptides. The acetonitrile concentration in conditioning and washing solutions played a key role; at 65% acetonitrile, glycopeptides were not retained on the SPE column and were detected in the flow-through fraction. Ultimately, it was proven that the enrichment method was applicable to human plasma samples, resulting in a significant decrease in the abundances of non-glycosylated peptides. To the best of our knowledge, this study represents the first systematic investigation into the impact of the mobile phase on glycopeptide enrichment using an aminopropyl-modified SPE column in HILIC mode. This study demonstrates the substantial impact of even minor variations in experimental conditions, which have not yet been considered in the literature, on SPE-HILIC glycopeptide enrichment. Consequently, meticulous optimization of these conditions is imperative to enhance the specificity and selectivity of glycoproteomic analysis, ensuring accurate and reliable quantification.

• Klíčová slova
• Glycopeptide enrichment, Glycoproteomics, Hydrophilic interaction liquid chromatography, Immunoglobulin G, Solid-phase extraction,
• MeSH
• 2-propanol MeSH
• acetáty MeSH
• acetonitrily MeSH
• chromatografie kapalinová metody   MeSH
• extrakce na pevné fázi metody   MeSH
• formiáty * MeSH
• glykopeptidy * chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• imunoglobulin G chemie   MeSH
• lidé MeSH
• methanol * MeSH
• rozpouštědla MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2-propanol MeSH
• acetáty MeSH
• acetonitrily MeSH
• formiáty * MeSH
• formic acid MeSH Prohlížeč
• glykopeptidy * MeSH
• imunoglobulin G MeSH
• methanol * MeSH
• rozpouštědla MeSH