One of the less studied in vitro biological activities in the aquatic environment are thyroid hormone receptor beta (TRβ)-mediated agonistic and antagonistic activities and transthyretin (TTR) binding activity. They were measured mostly using active sampling methods, but rarely found. It is unclear if these activities co-occur, and the drivers of the (anti-)TRβ activity are mostly unknown. Therefore, the main aim of the study was to determine (anti-)TRβ activities as well as transthyretin (TTR) binding activity in passive samplers from Czech surface waters in combination with the search for the effect drivers based on liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis by applying suspect screening. Passive samplers (polar organic chemical integrative samplers, POCIS) were deployed at twenty-one sites (all ends of watersheds and other important sites in Elbe River) in the Czech rivers. The (anti-)TRβ and TTR binding activity were measured using (anti-)TRβ-CALUX and TTR-TRβ-CALUX bioassays. Anti-TRβ activity was found at eight sites, and TTR binding activity co-occurred there at six of these sites. The co-occurrence of TRβ-mediated antagonistic activity and TTR binding indicate that they may have common effect drivers. No sample exhibited TRβ agonistic activity. The extract from the site Bílina River, the most burdened with anti-TRβ activity, was further successfully fractionated, and this activity was revealed in the fraction, where mid-polar compounds prevailed. However, the suspect LC-HRMS analysis did not reveal the chemical effect drivers. Our results showed that anti-TRβ activity can be found in surface waters by employing passive sampling and frequently co-occurs with TTR binding activity. Overall, the fractionation procedure and non-target data acquisition used in this study can serve as a basis for searching the effect drivers in future research.

• Klíčová slova
• Concentration addition, Effect-directed analysis, Fractionation, Thyroid hormone, Transporter protein,
• MeSH
• chemické látky znečišťující vodu analýza   MeSH
• chromatografie kapalinová metody   MeSH
• hmotnostní spektrometrie metody   MeSH
• monitorování životního prostředí * metody   MeSH
• prealbumin * metabolismus   MeSH
• receptory thyreoidních hormonů metabolismus   MeSH
• řeky * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• prealbumin * MeSH
• receptory thyreoidních hormonů MeSH

OBJECTIVE: The laboratory diagnosis of inherited metabolic disorders (IMD) has undergone significant development in recent decades, mainly due to the use of mass spectrometry, which allows rapid multicomponent analysis of a wide range of metabolites. Combined with advanced software tools, the diagnosis becomes more efficient as a benefit for both physicians and patients. METHODS: A hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry assay for determination of urinary purines, pyrimidines, N-acylglycines, N-acetylated amino acids, sugars, sugar alcohols and other diagnostically important biomarkers was developed and validated. Evaluation of the results consisting of utilisation of robust scaling and advanced visualization tools is simple and even suitable for urgent requirements. RESULTS: The developed method, covering 65 biomarkers, provides a comprehensive diagnostic platform for 51 IMD. For most analytes, linearity with R2 > 0.99, intra and inter-day accuracy between 80 and 120 % and precision lower than 20 % were achieved. Diagnostic workflow was evaluated on 47 patients and External Quality Assurance samples involving a total of 24 different IMD. Over seven years, more than 2300 urine samples from patients suspected for IMD have been routinely analysed. CONCLUSIONS: This method offers the advantage of a broad coverage of intermediate metabolites of interest and therefore may be a potential alternative and simplification for clinical laboratories that use multiple methods for screening these markers.

• Klíčová slova
• Diagnosis, Hydrophilic interaction chromatography, Inherited metabolic disorders, Liquid chromatography, Mass spectrometry,
• MeSH
• biologické markery moč   MeSH
• chromatografie kapalinová metody   MeSH
• kapalinová chromatografie-hmotnostní spektrometrie MeSH
• lidé MeSH
• metabolické nemoci * MeSH
• tandemová hmotnostní spektrometrie * metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické markery 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

Current state-of-the-art chiral stationary phases (CSPs) enable chiral resolution of almost any racemic mixture of choice. The exceptions represent ionizable and ionized substances that fail at any attempts to resolve on commercially available CSPs. These compounds, however, can be efficiently separated on chiral ion exchangers. Commercially available Cinchona alkaloids-based chiral weak ion-exchangers are typically used for chiral resolution of organic acids, while zwitterion ion-exchangers are efficient in the resolution of acids, bases, and zwitterions. The latter possess in their structure a cation exchange unit, which alone can serve as a cornerstone of chiral strong cation exchangers facilitating chiral separation of various basic racemic mixtures. Although chiral strong cation exchangers (cSCX) are efficient CSPs, their structural variations have not been thoroughly studied so far. It was assumed that the mechanism of chiral recognition of basic compounds by cSCX is based predominantly on π-π-interactions, hydrogen bonding and steric interactions (CSP I). To verify this assumption, we aimed in our study on the design and synthesis of cSCX first lacking lateral polar substituents on the aromatic unit in the selector's structure (CSP II), and second, to replace the aromatic unit by a cyclohexane ring (CSP III and IV), thereby to omit completely the π-π-interactions. We hypothesized that this structural change should lead to a partial or complete loss of enantiorecognition power of the selectors. Surprisingly, the non-aromatic cSCXs have shown chiral recognition capability comparable to that of previously described chiral cation exchange-type CSPs: from 16 analytes screened, 11 analytes were baseline resolved and 5 partially resolved on CSP I, while non-aromatic CSP III resolved 10 analytes baseline and 6 partially. We discuss the structural motifs of the known cSCX and the novel non-aromatic selectors in a relationship with their chromatographic performance using a set of basic analytes. Moreover, we present a theory of an effective chiral recognition mechanism by two novel non-aromatic cSCXs based on the chromatographic results and quantum mechanical calculations.

• Klíčová slova
• Chiral recognition, Chiral separation, Chiral stationary phases, Chiral strong cation exchangers, Molecular shape of selectors, π−π-interactions,
• MeSH
• chininové alkaloidy * chemie   MeSH
• chromatografie kapalinová metody   MeSH
• kationty MeSH
• kyseliny MeSH
• molekulární struktura MeSH
• stereoizomerie MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chininové alkaloidy * MeSH
• kationty MeSH
• kyseliny MeSH

Liquid chromatography with mass spectrometry (LC-MS)-based metabolomics detects thousands of molecular features (retention time-m/z pairs) in biological samples per analysis, yet the metabolite annotation rate remains low, with 90% of signals classified as unknowns. To enhance the metabolite annotation rates, researchers employ tandem mass spectral libraries and challenging in silico fragmentation software. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) may offer an additional layer of structural information in untargeted metabolomics, especially for identifying specific unidentified metabolites that are revealed to be statistically significant. Here, we investigate the potential of hydrophilic interaction liquid chromatography (HILIC)-HDX-MS in untargeted metabolomics. Specifically, we evaluate the effectiveness of two approaches using hypothetical targets: the post-column addition of deuterium oxide (D2O) and the on-column HILIC-HDX-MS method. To illustrate the practical application of HILIC-HDX-MS, we apply this methodology using the in silico fragmentation software MS-FINDER to an unknown compound detected in various biological samples, including plasma, serum, tissues, and feces during HILIC-MS profiling, subsequently identified as N1-acetylspermidine.

• Klíčová slova
• hydrogen/deuterium exchange, liquid chromatography, mass spectrometry, metabolomics, unknown identification,
• MeSH
• chromatografie kapalinová metody   MeSH
• deuterium MeSH
• hydrofobní a hydrofilní interakce MeSH
• metabolomika * metody   MeSH
• vodík/deuteriová výměna a hmotnostní spektrometrie * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• deuterium 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

BACKGROUND: Systemically administered antibiotics are thought to penetrate the wounds more effectively during negative pressure wound therapy (NPWT).To test this hypothesis total and free antibiotic concentrations were quantified in serum and wound exudate. METHODS: UHPLC-MS/MS methods were developed and validated for the determination of ceftazidime, cefepime, cefotaxime, cefuroxime, cefazolin, meropenem, oxacillin, piperacillin with tazobactam, clindamycin, ciprofloxacin, sulfamethoxazole/trimethoprim (cotrimoxazole), gentamicin, vancomycin, and linezolid. The unbound antibiotic fraction was obtained by ultrafiltration using a Millipore Microcon-30kda Centrifugal Filter Unit. Analysis was performed on a 1.7-µm Acquity UPLC BEH C18 2.1 × 100-mm column with a gradient elution. RESULTS: The validation was performed for serum, exudates and free fractions. For all matrices, requirements were met regarding linearity, precision, accuracy, limit of quantitation, and matrix effect. The coefficient of variation was in the range of 1.2-13.6%.and the recovery 87.6-115.6%, respectively. Among the 29 applications of antibiotics thus far, including vancomycin, clindamycin, ciprofloxacin, oxacillin, cefepime, cefotaxime, cotrimoxazole, and gentamicin, total and free antibiotic concentrations in serum and exudate were correlated. CONCLUSION: This method can accurately quantify the total and free concentrations of 16 antibiotics. Comparison of concentration ratios between serum and exudates allows for monitoring individual antibiotics' penetration capacity in patients receiving NPWT.

• Klíčová slova
• Cardiac surgery, Exudate, Method validation, Negative pressure wound therapy, Serum, Total and free antibiotic concentration,
• MeSH
• antibakteriální látky MeSH
• cefepim MeSH
• cefotaxim MeSH
• chromatografie kapalinová metody   MeSH
• ciprofloxacin MeSH
• exsudáty a transsudáty MeSH
• gentamiciny MeSH
• infekce v ráně * MeSH
• klindamycin MeSH
• kombinace léků trimethoprim a sulfamethoxazol MeSH
• lidé MeSH
• oxacilin MeSH
• sternotomie MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• terapie ran pomocí řízeného podtlaku * MeSH
• vankomycin MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• cefepim MeSH
• cefotaxim MeSH
• ciprofloxacin MeSH
• gentamiciny MeSH
• klindamycin MeSH
• kombinace léků trimethoprim a sulfamethoxazol MeSH
• oxacilin MeSH
• vankomycin MeSH

Unusual glucose-substituted cardiolipins (Glcx-CLs) in three genera of thermophilic bacteria, having more than one glycosidically linked glucose to the hydroxyl of the central glycerol of Glcx-CLs were identified for the first time in thermophilic bacteria of the genera Geobacillus, Meiothermus, and Thermus. The number of glucoses reached up to five units. The structure of glycosidically linked oligosaccharides was determined based on shotgun analysis MS (electrospray high-resolution tandem mass spectrometry), partially methylated alditol acetates were identified by GC-MS, both electron ionization (EI) and positive chemical ionization (PCI), hydrophilic interaction liquid chromatography (HILIC) separation and identification of CLs glycosides by high resolution MS-ESI, and digestion by specific glycosidases.

• Klíčová slova
• Electrospray mass spectrometry, Glucosyl-cardiolipins, Hydrophilic interaction liquid chromatography, Partially methylated alditol acetates, Thermophilic bacteria,
• MeSH
• Bacteria MeSH
• chromatografie kapalinová metody   MeSH
• glukosa MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• kardiolipiny * analýza   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• tandemová hmotnostní spektrometrie * metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa MeSH
• kardiolipiny * MeSH

Determination of the various forms of vitamin K, which are involved in coagulation and other physiological processes in humans, is challenging and no standardized method is yet available. Therefore, a reliable and practical method was developed to quantify vitamin K levels in serum and additionally in lipoprotein fractions to clarify its distribution. The LC-MS/MS method for the determination of vitamin K1 and the three main isoforms of vitamin K2 (MK-4, MK-7, MK-9) was combined with a gradient ultracentrifugation technique to allow the separation of lipoprotein fractions. The chromatographic separation was carried out on a Kinetex™ C18 column using a mobile phase consisting mainly of methanol. The target analytes were detected by electrospray ionization mass spectrometry. The separation of all four substances was achieved after a simple sample preparation technique based on miniaturized liquid-liquid extraction. Our method of only 8.5 min revealed the levels of the major forms of vitamin K in 59 human and 12 rat sera and confirmed our hypothesis that vitamin K is primarily (about 50 %) found in the high-density lipoprotein fraction. The median concentrations of vitamin K1, MK-4, MK-7, and MK-9 were found to be 1.19, 2.98, 0.43, and < 0.71 nmol/L in human serum and 1.74, 6.75, less than 0.2, and less than 0.5 nmol/L in rat serum, respectively.

• Klíčová slova
• Bioanalysis, Menaquinone, Phylloquinone, UHPLC-MS/MS, Ultracentrifugation,
• MeSH
• chromatografie kapalinová metody   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• lipoproteiny MeSH
• tandemová hmotnostní spektrometrie * metody   MeSH
• vitamin K 1 * chemie   MeSH
• vitamin K 2 chemie   MeSH
• vitamin K MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• lipoproteiny MeSH
• vitamin K 1 * MeSH
• vitamin K 2 MeSH
• vitamin K MeSH

Microflow liquid chromatography interfaced with mass spectrometry (μLC-MS/MS) is increasingly applied for high-throughput profiling of biological samples and has been proven to have an acceptable trade-off between sensitivity and reproducibility. However, lipidomics applications are scarce. We optimized a μLC-MS/MS system utilizing a 1 mm inner diameter × 100 mm column coupled to a triple quadrupole mass spectrometer to establish a sensitive, high-throughput, and robust single-shot lipidomics workflow. Compared to conventional lipidomics methods, we achieve a ∼4-fold increase in response, facilitating quantification of 351 lipid species from a single iPSC-derived cerebral organoid during a 15 min LC-MS analysis. Consecutively, we injected 303 samples over ∼75 h to prove the robustness and reproducibility of the microflow separation. As a proof of concept, μLC-MS/MS analysis of Alzheimer's disease patient-derived iPSC cerebral organoid reveals differential lipid metabolism depending on APOE phenotype (E3/3 vs E4/4). Microflow separation proves to be an environmentally friendly and cost-effective method as it reduces the consumption of harmful solvents. Also, the data demonstrate robust, in-depth, high-throughput performance to enable routine clinical or biomedical applications.

• MeSH
• apolipoproteiny E MeSH
• chromatografie kapalinová metody   MeSH
• fenotyp MeSH
• kapalinová chromatografie-hmotnostní spektrometrie * MeSH
• lidé MeSH
• lipidomika MeSH
• reprodukovatelnost výsledků MeSH
• tandemová hmotnostní spektrometrie * metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• apolipoproteiny E MeSH