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1.
World J Urol ; 42(1): 353, 2024 May 25.
Article in English | MEDLINE | ID: mdl-38795133

ABSTRACT

PURPOSE: Despite many efforts, no reliable urinary marker system has so far shown the potential to substitute cystoscopy. Measuring volatile organic compounds (VOCs) from urine is a promising alternative. VOCs are metabolic products which can be measured from the headspace of urine samples. Previous studies confirmed that the urine of bladder tumor patients has a different VOC profile than healthy controls. In this pilot study, the feasibility of discriminating VOCs from urine of bladder cancer patients from that of healthy control subjects was investigated. Aim of this study was to investigate whether VOC-based diagnosis of bladder cancer from urine samples is feasible using multicapillary column ion mobility spectrometry (MCC/IMS) and to identify potential molecular correlates to the relevant analytes. METHODS: Headspace measurements of urine samples of 30 patients with confirmed transitional cell carcinoma (TCC) and 30 healthy controls were performed using MCC/IMS. In the results of the measurements, peaks showing significant differences between both groups were identified and implemented into a decision tree with respect to achieve group separation. Molecular correlates were predicted using a pre-defined dataset. RESULTS: Eight peaks with significantly differing intensity were identified, 5 of which were highly significant. Using a six-step decision tree, MCC/IMS showed a sensitivity of 90% and specificity of 100% in group separation. CONCLUSION: VOC-based detection of bladder cancer is feasible. MCC/IMS is a suitable method for urine-based diagnosis and should be further validated. The molecular characteristics and metabolic background of the analytes require further workup.


Subject(s)
Carcinoma, Transitional Cell , Ion Mobility Spectrometry , Urinary Bladder Neoplasms , Volatile Organic Compounds , Humans , Urinary Bladder Neoplasms/urine , Urinary Bladder Neoplasms/diagnosis , Volatile Organic Compounds/urine , Pilot Projects , Ion Mobility Spectrometry/methods , Male , Female , Aged , Middle Aged , Carcinoma, Transitional Cell/urine , Carcinoma, Transitional Cell/diagnosis , Feasibility Studies , Aged, 80 and over , Biomarkers, Tumor/urine
2.
J Mass Spectrom ; 59(6): e5039, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38747242

ABSTRACT

Utilizing a data-driven approach, this study investigates modifier effects on compensation voltage in differential mobility spectrometry-mass spectrometry (DMS-MS) for metabolites and peptides. Our analysis uncovers specific factors causing signal suppression in small molecules and pinpoints both signal suppression mechanisms and the analytes involved. In peptides, machine learning models discern a relationship between molecular weight, topological polar surface area, peptide charge, and proton transfer-induced signal suppression. The models exhibit robust performance, offering valuable insights for the application of DMS to metabolites and tryptic peptides analysis by DMS-MS.


Subject(s)
Ion Mobility Spectrometry , Metabolomics , Peptides , Metabolomics/methods , Peptides/chemistry , Peptides/analysis , Ion Mobility Spectrometry/methods , Mass Spectrometry/methods , Machine Learning , Proteomics/methods , Molecular Weight
3.
Anal Chem ; 96(19): 7380-7385, 2024 May 14.
Article in English | MEDLINE | ID: mdl-38693701

ABSTRACT

Ion mobility-mass spectrometry (IM-MS) offers benefits for lipidomics by obtaining IM-derived collision cross sections (CCS), a conditional property of an ion that can enhance lipid identification. While drift tube (DT) IM-MS retains a direct link to the primary experimental method to derive CCS values, other IM technologies rely solely on external CCS calibration, posing challenges due to dissimilar chemical properties between lipids and calibrants. To address this, we introduce MobiLipid, a novel tool facilitating the CCS quality control of IM-MS lipidomics workflows by internal standardization. MobiLipid utilizes a newly established DTCCSN2 library for uniformly (U)13C-labeled lipids, derived from a U13C-labeled yeast extract, containing 377 DTCCSN2 values. This automated open-source R Markdown tool enables internal monitoring and straightforward compensation for CCSN2 biases. It supports lipid class- and adduct-specific CCS corrections, requiring only three U13C-labeled lipids per lipid class-adduct combination across 10 lipid classes without requiring additional external measurements. The applicability of MobiLipid is demonstrated for trapped IM (TIM)-MS measurements of an unlabeled yeast extract spiked with U13C-labeled lipids. Monitoring the CCSN2 biases of TIMCCSN2 values compared to DTCCSN2 library entries utilizing MobiLipid resulted in mean absolute biases of 0.78% and 0.33% in positive and negative ionization mode, respectively. By applying the CCS correction integrated into the tool for the exemplary data set, the mean absolute CCSN2 biases of 10 lipid classes could be reduced to approximately 0%.


Subject(s)
Lipidomics , Lipids , Mass Spectrometry , Lipidomics/methods , Lipids/chemistry , Lipids/analysis , Ion Mobility Spectrometry/methods , Quality Control , Reference Standards , Saccharomyces cerevisiae/chemistry , Saccharomyces cerevisiae/metabolism
4.
Sensors (Basel) ; 24(9)2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38732837

ABSTRACT

The gut microbiota and its related metabolites differ between inflammatory bowel disease (IBD) patients and healthy controls. In this study, we compared faecal volatile organic compound (VOC) patterns of paediatric IBD patients and controls with gastrointestinal symptoms (CGIs). Additionally, we aimed to assess if baseline VOC profiles could predict treatment response in paediatric IBD patients. We collected faecal samples from a cohort of de novo therapy-naïve paediatric IBD patients and CGIs. VOCs were analysed using gas chromatography-ion mobility spectrometry (GC-IMS). Response was defined as a combination of clinical response based on disease activity scores, without requiring treatment escalation. We included 109 paediatric IBD patients and 75 CGIs, aged 4 to 17 years. Faecal VOC profiles of paediatric IBD patients were distinguishable from those of CGIs (AUC ± 95% CI, p-values: 0.71 (0.64-0.79), <0.001). This discrimination was observed in both Crohn's disease (CD) (0.75 (0.67-0.84), <0.001) and ulcerative colitis (UC) (0.67 (0.56-0.78), 0.01) patients. VOC profiles between CD and UC patients were not distinguishable (0.57 (0.45-0.69), 0.87). Baseline VOC profiles of responders did not differ from non-responders (0.70 (0.58-0.83), 0.1). In conclusion, faecal VOC profiles of paediatric IBD patients differ significantly from those of CGIs.


Subject(s)
Feces , Inflammatory Bowel Diseases , Ion Mobility Spectrometry , Volatile Organic Compounds , Humans , Volatile Organic Compounds/analysis , Child , Feces/chemistry , Adolescent , Female , Male , Case-Control Studies , Child, Preschool , Ion Mobility Spectrometry/methods , Inflammatory Bowel Diseases/metabolism , Crohn Disease/metabolism , Colitis, Ulcerative/metabolism , Gas Chromatography-Mass Spectrometry/methods , Gastrointestinal Microbiome/physiology
5.
J Physiol Pharmacol ; 75(2): 215-222, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38736268

ABSTRACT

The analysis of volatile organic compounds (VOCs) present in various biological samples holds immense potential for non-invasive disease diagnostics and metabolic profiling. One of the biological fluids that are suitable for use in clinical practice is urine. Given the limited quantity of VOCs in the urine headspace, it's imperative to enhance their extraction into the gaseous phase and prevent any degradation of VOCs during the thawing process. The study aimed to test several key parameters (incubation time, temperature, and thawing) that can influence urine volatilome and monitor selected VOCs for their stability. The analysis in this study was performed using a BreathSpec® (G.A.S., Dortmund, Germany) device consisting of a gas chromatograph (GC) coupled with an ion mobility spectrometer (IMS). Testing three different temperatures and incubation times yielded a low number of VOCs (9 out of 34) that exhibited statistically significant differences. However, examining three thawing conditions revealed no VOCs with statistically significant changes. Thus, we conclude that urine composition remains relatively stable despite exposure to various thermal stresses.


Subject(s)
Ion Mobility Spectrometry , Volatile Organic Compounds , Volatile Organic Compounds/urine , Volatile Organic Compounds/analysis , Humans , Pilot Projects , Ion Mobility Spectrometry/methods , Male , Adult , Gas Chromatography-Mass Spectrometry/methods , Female , Temperature , Young Adult , Middle Aged
6.
J Chromatogr A ; 1725: 464931, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38703457

ABSTRACT

Atractylodis rhizoma is a common bulk medicinal material with multiple species. Although different varieties of atractylodis rhizoma exhibit variations in their chemical constituents and pharmacological activities, they have not been adequately distinguished due to their similar morphological features. Hence, the purpose of this research is to analyze and characterize the volatile organic compounds (VOCs) in samples of atractylodis rhizoma using multiple techniques and to identify the key differential VOCs among different varieties of atractylodis rhizoma for effective discrimination. The identification of VOCs was carried out using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), resulting in the identification of 60 and 53 VOCs, respectively. The orthogonal partial least squares discriminant analysis (OPLS-DA) model was employed to screen potential biomarkers and based on the variable importance in projection (VIP ≥ 1.2), 24 VOCs were identified as critical differential compounds. Random forest (RF), K-nearest neighbor (KNN) and back propagation neural network based on genetic algorithm (GA-BPNN) models based on potential volatile markers realized the greater than 90 % discriminant accuracies, which indicates that the obtained key differential VOCs are reliable. At the same time, the aroma characteristics of atractylodis rhizoma were also analyzed by ultra-fast gas chromatography electronic nose (Ultra-fast GC E-nose). This study indicated that the integration of HS-SPME-GC-MS, HS-GC-IMS and ultra-fast GC E-nose with chemometrics can comprehensively reflect the differences of VOCs in atractylodis rhizoma samples from different varieties, which will be a prospective tool for variety discrimination of atractylodis rhizoma.


Subject(s)
Atractylodes , Electronic Nose , Gas Chromatography-Mass Spectrometry , Solid Phase Microextraction , Volatile Organic Compounds , Volatile Organic Compounds/analysis , Gas Chromatography-Mass Spectrometry/methods , Solid Phase Microextraction/methods , Atractylodes/chemistry , Ion Mobility Spectrometry/methods , Rhizome/chemistry , Discriminant Analysis
7.
Rapid Commun Mass Spectrom ; 38(15): e9775, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-38807480

ABSTRACT

RATIONALE: Spironolactone is a steroidal drug prescribed for a variety of medical conditions and is extensively metabolized quickly after administration. Measurement of spironolactone and its metabolites remains challenging using mass spectrometry (MS) due to in-source fragmentation and relatively poor ionization using electrospray ionization. Therefore, improved methods of measurements are needed, particularly in the case of small sample volumes. METHODS: Girard's reagent P (GP) derivatization of spironolactone was employed to improve response and provide an MS-based solution to the measurement of spironolactone and its metabolites. We performed ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) and ion mobility spectrometry (IMS)-high-resolution mass spectrometry (HRMS) to fully characterize the GP derivatization products. Analytes were studied in positive ionization mode, and MS/MS was performed using nonresonance and resonance excitation collision-induced dissociation. RESULTS: We observed the successful GP derivatization of spironolactone and its metabolites using authentic chemical standards. A signal enhancement of 1-2 orders of magnitude was observed for GP-derivatized versions of spironolactone and its metabolites. Further, GP derivatization eliminated in-source fragmentation. Finally, we performed GP derivatization and ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) in a small volume of murine serum (20 µL) from spironolactone-treated and control animals and observed multiple spironolactone metabolites only in the spironolactone-treated group. CONCLUSIONS: GP derivatization was proven to have advantageous mass spectral performance (e.g., limiting in-source fragmentation, enhancing signals, and eliminating isobaric analytes) for spironolactone and its metabolites. This work and the detailed characterization using ultra-high-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) and IMS serve as the foundation for future developments in reaction optimization and/or quantitative assay development.


Subject(s)
Ion Mobility Spectrometry , Spectrometry, Mass, Electrospray Ionization , Spironolactone , Tandem Mass Spectrometry , Spironolactone/chemistry , Spironolactone/blood , Spironolactone/metabolism , Chromatography, High Pressure Liquid/methods , Animals , Tandem Mass Spectrometry/methods , Mice , Spectrometry, Mass, Electrospray Ionization/methods , Ion Mobility Spectrometry/methods , Male
8.
J Breath Res ; 18(3)2024 May 17.
Article in English | MEDLINE | ID: mdl-38701772

ABSTRACT

The analysis of volatile organic compounds (VOCs) in exhaled air has attracted the interest of the scientific community because it provides the possibility of monitoring physiological and metabolic processes and non-invasive diagnostics of various diseases. However, this method remains underused in clinical practice as well as in research because of the lack of standardized procedures for the collection, storage and transport of breath samples, which would guarantee good reproducibility and comparability of results. The method of sampling, as well as the storage time of the breath samples in the polymer bags used for sample storage and transport, affect the composition and concentration of VOCs present in the breath samples. The aim of our study was to compare breath samples obtained using two methods with fully disposable equipment: a Haldane sampling tube intended for direct breath collection and breath samples exhaled into a transparent Tedlar bag. The second task was to monitor the stability of selected compounds of real breath samples stored in a Tedlar bag for 6 h. Gas chromatography coupled with ion mobility spectrometry (GC-IMS) implemented in the BreathSpec®device was used to analyse exhaled breath. Our results showed a significant difference in the signal intensity of some volatiles when taking a breath sample with a Haldane tube and a Tedlar bag. Due to its endogenous origin, acetone levels were significantly higher when the Haldane tube sampler was used while elevated levels of 2-propanol and unidentified VOC (designated as VOC 3) in the Tedlar bag samples likely originated from contamination of the Tedlar bags. The VOC stability study revealed compound-specific signal intensity changes of the selected VOCs with storage time in the Tedlar bags, with some volatiles showing increasing signal intensity during storage in Tedlar bags. This limits the use of Tedlar bags only for very limited time and carefully selected purpose. Our results highlight the importance of careful design and implementation of experiments and clinical protocols to obtain relevant and reliable results.


Subject(s)
Breath Tests , Specimen Handling , Volatile Organic Compounds , Humans , Breath Tests/instrumentation , Breath Tests/methods , Volatile Organic Compounds/analysis , Specimen Handling/instrumentation , Specimen Handling/methods , Ion Mobility Spectrometry/methods , Ion Mobility Spectrometry/instrumentation , Male , Female , Reproducibility of Results , Adult , Gas Chromatography-Mass Spectrometry/methods , Gas Chromatography-Mass Spectrometry/instrumentation , Exhalation , Middle Aged , Time Factors
9.
J Am Chem Soc ; 146(21): 14468-14478, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38757172

ABSTRACT

Many biological mechanisms rely on the precise control of conformational changes in proteins. Understanding such dynamic processes requires methods for determining structures and their temporal evolution. In this study, we introduce a novel approach to time-resolved ion mobility mass spectrometry. We validated the method on a simple photoreceptor model and applied it to a more complex system, the animal-like cryptochrome from Chlamydomonas reinhardtii (CraCRY), to determine the role of specific amino acids affecting the conformational dynamics as reaction to blue light activation. In our setup, using a high-power LED mounted in the source region of an ion mobility mass spectrometer, we allow a time-resolved evaluation of mass and ion mobility spectra. Cryptochromes like CraCRY are a widespread type of blue light photoreceptors and mediate various light-triggered biological functions upon excitation of their inbuilt flavin chromophore. Another hallmark of cryptochromes is their flexible carboxy-terminal extension (CTE), whose structure and function as well as the details of its interaction with the photolyase homology region are not yet fully understood and differ among different cryptochromes types. Here, we addressed the highly conserved C-terminal domain of CraCRY, to study the effects of single mutations on the structural transition of the C-terminal helix α22 and the attached CTE upon lit-state formation. We show that D321, the putative proton acceptor of the terminal proton-coupled electron transfer event from Y373, is essential for triggering the large-scale conformational changes of helix α22 and the CTE in the lit state, while D323 influences the timing.


Subject(s)
Chlamydomonas reinhardtii , Cryptochromes , Protein Conformation , Cryptochromes/chemistry , Cryptochromes/metabolism , Chlamydomonas reinhardtii/chemistry , Chlamydomonas reinhardtii/metabolism , Mass Spectrometry/methods , Ion Mobility Spectrometry/methods , Models, Molecular
10.
Protein Sci ; 33(6): e5008, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38723181

ABSTRACT

One of the most important attributes of anti-amyloid antibodies is their selective binding to oligomeric and amyloid aggregates. However, current methods of examining the binding specificities of anti-amyloid ß (Aß) antibodies have limited ability to differentiate between complexes that form between antibodies and monomeric or oligomeric Aß species during the dynamic Aß aggregation process. Here, we present a high-resolution native ion-mobility mass spectrometry (nIM-MS) method to investigate complexes formed between a variety of Aß oligomers and three Aß-specific IgGs, namely two antibodies with relatively high conformational specificity (aducanumab and A34) and one antibody with low conformational specificity (crenezumab). We found that crenezumab primarily binds Aß monomers, while aducanumab preferentially binds Aß monomers and dimers and A34 preferentially binds Aß dimers, trimers, and tetrameters. Through collision induced unfolding (CIU) analysis, our data indicate that antibody stability is increased upon Aß binding and, surprisingly, this stabilization involves the Fc region. Together, we conclude that nIM-MS and CIU enable the identification of Aß antibody binding stoichiometries and provide important details regarding antibody binding mechanisms.


Subject(s)
Amyloid beta-Peptides , Antibodies, Monoclonal, Humanized , Ion Mobility Spectrometry , Amyloid beta-Peptides/chemistry , Amyloid beta-Peptides/immunology , Amyloid beta-Peptides/metabolism , Antibodies, Monoclonal, Humanized/chemistry , Antibodies, Monoclonal, Humanized/immunology , Antibodies, Monoclonal, Humanized/metabolism , Ion Mobility Spectrometry/methods , Humans , Mass Spectrometry/methods , Protein Binding , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Protein Multimerization
11.
J Chromatogr A ; 1722: 464903, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38615559

ABSTRACT

High-Field Asymmetric Ion Mobility Spectrometry (FAIMS) is a technique for ion separation and detection based on ion mobility variation under high electronic field. While compensation voltage scanning speed is a fundamental parameter in FAIMS, its impact on spectra remains unclear. In this work, a function referred to as F-EMG is introduced to describe the impact of compensation voltage scanning speed on FAIMS spectra, and the properties of the function are studied. Theoretical analysis emphasizes the impact of the scanning speed on peak height, position, and symmetry, as well as the capability of the F-EMG function to progressively approach Gaussian function at lower scanning speeds. Furthermore, the function indicates that spectra obtained in positive and negative scanning modes exhibits symmetry. An experimental validation, conducted with a custom FAIMS setup and analyzing hydrogen sulfide, ethylbenzene, toluene, styrene, benzene and ammonia, confirms the model's influence on peak features, fitting accuracy, and exhibits a closer alignment with the Gaussian function at lower scanning speeds. Additionally, the experimental data indicate that the spectra show symmetry in positive and negative scanning models. This work not only improves understanding of FAIMS spectral analysis but also introduces a robust method for enhancing data accuracy across varying scanning speeds.


Subject(s)
Ion Mobility Spectrometry , Ion Mobility Spectrometry/methods , Models, Theoretical , Ions/chemistry , Ions/analysis
12.
J Am Soc Mass Spectrom ; 35(5): 1012-1020, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38634722

ABSTRACT

To understand the mode of action of bioactive oligosaccharides, such as prebiotics, in-depth knowledge about all structural features, including monosaccharide composition, linkage type, and anomeric configuration, is necessary. Current analytical techniques provide limited information about structural features within complex mixtures unless preceded by extensive purification. In this study, we propose an approach employing cyclic ion mobility spectrometry (cIMS) for the in-depth characterization of oligosaccharides, here demonstrated for disaccharides. We were able to separate galactose and glucose anomers by exploiting the high ion mobility resolution of cIMS. Using the obtained monosaccharide mobilograms as references, we determined the composition and anomeric configuration of 4ß-galactobiose by studying the monosaccharide fragments generated by collision-induced dissociation (CID) before the ion mobility separation. Drift times and individual MS2 spectra of partially resolved reducing-end anomers of 4ß-galactobiose, 4ß-galactosylglucose (lactose), and 4ß-glucosylglucose (cellobiose) were obtained by deconvolution using CID fragmentation induced in the transfer region between the cIMS cell and TOF analyzer. The composition and anomeric configuration of the reducing end anomers of these disaccharides were identified using cIMS2 approaches, where first each anomer was isolated using cIMS and individually fragmented, and the monosaccharide fragments were again separated by cIMS for comparison with monosaccharide standards. With these results we demonstrate the promising application of cIMS for the structural characterization of isomeric oligosaccharides.


Subject(s)
Disaccharides , Ion Mobility Spectrometry , Monosaccharides , Ion Mobility Spectrometry/methods , Disaccharides/chemistry , Monosaccharides/chemistry , Carbohydrate Conformation
13.
J Am Soc Mass Spectrom ; 35(5): 982-991, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38597281

ABSTRACT

The structural characterization and differentiation of four types of oligoubiquitin conjugates [linear (Met1)-, Lys11-, Lys48-, Lys63-linked di-, tri-, and tetraubiquitin chains] using ion mobility mass spectrometry are reported. A comparison of collision cross sections for the same linkage of di-, tri-, and tetraubiquitin chains shows differences in conformational elongation for higher charge states due to the interplay of linkage-derived structure and Coulombic repulsion. For di- and triubiquitin chains, this elongation results in a single narrow feature representing an elongated conformation type for multiple higher charge state species. In contrast, higher charge state tetraubiquitin species do not form a single conformer type as readily. A comparison of different linkages in tetraubiquitin chains reveals greater similarity in conformation type at lower charge states; with increasing charge state, the four linkage types diverge in the relative proportions of elongated conformer types with Met1- ≥ Lys11- > Lys63- > Lys48-linkage. These differences in conformational trends could be discussed with respect to biological functions of linkage-specific polyubiquitinated proteins.


Subject(s)
Ion Mobility Spectrometry , Ubiquitin , Ion Mobility Spectrometry/methods , Ubiquitin/chemistry , Protein Conformation , Mass Spectrometry/methods , Models, Molecular , Lysine/chemistry
14.
Sci Total Environ ; 929: 172483, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38631629

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) remain controversial due to their high persistency and potential human toxicity. Although occupational exposure to PFAS has been widely investigated, the implications of PFAS occurrence in the general population remain to be unraveled. Considering that serum from most people contains PFAS, the aim of this study was to characterize the lipidomic profile in human serum from a general cohort (n = 40) with residual PFAS levels. The geometric means of ∑PFAS (11.8 and 4.4 ng/mL) showed significant differences (p < 0.05) for the samples with the highest (n = 20) and lowest (n = 20) concentrations from the general population respectively. Reverse-phase liquid chromatography coupled to drift tube ion mobility and high-resolution mass spectrometry using dual polarity ionization was used to characterize the lipid profile in both groups. The structural elucidation involved the integration of various parameters, such as retention time, mass-to-charge ratio, tandem mass spectra and collision cross section values. This approach yielded a total of 20 potential biomarkers linked to the perturbed glycerophospholipid metabolism, energy metabolism and sphingolipid metabolism. Among these alterations, most lipids were down-regulated and some specific lipids (PC 36:5, PC 37:4 and PI O-34:2) exhibited a relatively strong Spearman correlation and predictive capacity for PFAS contamination. This study could support further toxicological assessments and mechanistic investigations into the effects of PFAS exposure on the lipidome.


Subject(s)
Environmental Pollutants , Fluorocarbons , Lipidomics , Humans , Fluorocarbons/blood , Environmental Pollutants/blood , Chromatography, Liquid , China , Mass Spectrometry , Cohort Studies , Adult , Male , Environmental Exposure/statistics & numerical data , Female , Middle Aged , Ion Mobility Spectrometry/methods , Lipids/blood , Environmental Monitoring/methods , East Asian People
15.
Anal Chem ; 96(18): 7111-7119, 2024 May 07.
Article in English | MEDLINE | ID: mdl-38648270

ABSTRACT

Unsaturated lipids constitute a significant portion of the lipidome, serving as players of multifaceted functions involving cellular signaling, membrane structure, and bioenergetics. While derivatization-assisted liquid chromatography tandem mass spectrometry (LC-MS/MS) remains the gold standard technique in lipidome, it mainly faces challenges in efficiently labeling the carbon-carbon double bond (C═C) and differentiating isomeric lipids in full dimension. This presents a need for new orthogonal methodologies. Herein, a metal- and additive-free aza-Prilezhaev aziridination (APA)-enabled ion mobility mass spectrometric method is developed for probing multiple levels of unsaturated lipid isomerization with high sensitivity. Both unsaturated polar and nonpolar lipids can be efficiently labeled in the form of N-H aziridine without significant side reactions. The signal intensity can be increased by up to 3 orders of magnitude, achieving the nM detection limit. Abundant site-specific fragmentation ions indicate C═C location and sn-position in MS/MS spectra. Better yet, a stable monoaziridination product is dominant, simplifying the spectrum for lipids with multiple double bonds. Coupled with a U-shaped mobility analyzer, identification of geometric isomers and separation of different lipid classes can be achieved. Additionally, a unique pseudo MS3 mode with UMA-QTOF MS boosts the sensitivity for generating diagnostic fragments. Overall, the current method provides a comprehensive solution for deep-profiling lipidomics, which is valuable for lipid marker discovery in disease monitoring and diagnosis.


Subject(s)
Aziridines , Lipids , Aziridines/chemistry , Lipids/chemistry , Lipids/analysis , Isomerism , Tandem Mass Spectrometry/methods , Ion Mobility Spectrometry/methods
16.
J Mass Spectrom ; 59(5): e5013, 2024 May.
Article in English | MEDLINE | ID: mdl-38605450

ABSTRACT

Ion mobility spectrometry coupled to mass spectrometry (IMS/MS) is a widely used tool for biomolecular separations and structural elucidation. The application of IMS/MS has resulted in exciting developments in structural proteomics and genomics. This perspective gives a brief background of the field, addresses some of the important issues in making structural measurements, and introduces complementary techniques.


Subject(s)
Proteins , Proteomics , Proteins/analysis , Mass Spectrometry/methods , Ion Mobility Spectrometry/methods
17.
J Mass Spectrom ; 59(5): e5021, 2024 May.
Article in English | MEDLINE | ID: mdl-38605451

ABSTRACT

Trapped ion mobility spectrometry-time-of-flight mass spectrometry (TIMS-TOFMS) has emerged as a tool to study protein conformational states. In TIMS, gas-phase ions are guided across the IM stages by applying direct current (DC) potentials (D1-6), which, however, might induce changes in protein structures through collisional activation. To define conditions for native protein analysis, we evaluated the influence of these DC potentials using the metalloenzyme bovine carbonic anhydrase (BCA) as primary test compound. The variation of DC potentials did not change BCA-ion charge and heme content but affected (relative) charge-state intensities and adduct retention. Constructed extracted-ion mobilograms and corresponding collisional cross-section (CCS) profiles gave useful insights in (alterations of) protein conformational state. For BCA, the D3 and D6 potential (which are applied between the deflection transfer and funnel 1 [F1] and the accumulation exit and the start of the ramp, respectively) had most profound effects, showing multimodal CCS distributions at higher potentials indicating gradual unfolding. The other DC potentials only marginally altered the CCS profiles of BCA. To allow for more general conclusions, five additional proteins of diverse molecular weight and conformational stability were analyzed, and for the main protein charge states, CCS profiles were constructed. Principal component analysis (PCA) of the obtained data showed that D1 and D3 exhibit the highest degree of correlation with the ratio of folded and unfolded protein (F/U) as extracted from the mobilograms obtained per set D potential. The correlation of D6 with F/U and protein charge were similar, and D2, D4, and D5 showed an inverse correlation with F/U but were correlated with protein charge. Although DC boundary values for induced conformational changes appeared protein dependent, a set of DC values could be determined, which assured native analysis of most proteins.


Subject(s)
Ion Mobility Spectrometry , Proteins , Animals , Cattle , Ion Mobility Spectrometry/methods , Mass Spectrometry/methods , Protein Conformation , Proteins/chemistry , Ions
18.
J Mass Spectrom ; 59(5): e5026, 2024 May.
Article in English | MEDLINE | ID: mdl-38656572

ABSTRACT

Identification and specific quantification of isomers in a complex biological matrix by mass spectrometry alone is not an easy task due to their identical chemical formula and therefore their same mass-to-charge ratio (m/z). Here, the potential of direct introduction combined with ion mobility-mass spectrometry (DI-IM-MS) for rapid quantification of isomers as human milk oligosaccharides (HMOs) was investigated. Differences in HMO profiles between various analyzed breast milk samples were highlighted using the single ion mobility monitoring (SIM2) acquisition for high ion mobility resolution detection. Furthermore, the Se+ (secretor) or Se- (non-secretor) phenotype could be assigned to breast milk samples studied based on their HMO contents, especially on the response of 2'-fucosyllactose (2'-FL) and lacto-N-fucopentaose I (LNFP I). The possibility of quantifying a specific isomer in breast milk by DI-IM-MS was also investigated. The standard addition method allowed the determination of the 2'-FL despite the presence of other oligosaccharides, including 3-fucosyllactose (3-FL) isomer in breast milk. This proof-of-concept study demonstrated the high potential of such an approach for the rapid and convenient quantification of isomers in complex mixtures.


Subject(s)
Ion Mobility Spectrometry , Milk, Human , Oligosaccharides , Trisaccharides , Milk, Human/chemistry , Humans , Trisaccharides/analysis , Trisaccharides/chemistry , Oligosaccharides/analysis , Oligosaccharides/chemistry , Isomerism , Female , Ion Mobility Spectrometry/methods , Mass Spectrometry/methods
19.
Molecules ; 29(8)2024 Apr 19.
Article in English | MEDLINE | ID: mdl-38675693

ABSTRACT

Further assessment of ultraviolet C light-emitting diode (UVC-LED) irradiation for influencing shiitake mushrooms' (Lentinus edodes) volatile and sensory properties is needed. In this study, a comparison of UVC-LED irradiation treatment on the flavor profiles in various parts of shiitake mushrooms was conducted using gas chromatography-ion mobility spectrometry (GC-IMS) and sensory analysis. Sixty-three volatile compounds were identified in shiitake mushrooms. The fresh shiitake mushrooms were characterized by the highest values of raw mushroom odors. After UVC-LED treatment, the content of C8 alcohols decreased, especially that of 1-octen-3-ol, while the content of aldehydes increased, especially the content of nonanal and decanal. The score of fatty and green odors was enhanced. For fresh samples, the mushroom odors decreased and the mushroom-like odors weakened more sharply when treated in ethanol suspension than when treated with direct irradiation. The fruit odors were enhanced using direct UVC-LED irradiation for fresh mushroom samples and the onion flavor decreased. As for shiitake mushroom powder in ethanol suspension treated with UVC-LED, the sweaty and almond odor scores decreased and the vitamin D2 content in mushroom caps and stems reached 668.79 µg/g (dw) and 399.45 µg/g (dw), respectively. The results obtained from this study demonstrate that UVC-LED treatment produced rich-flavored, quality mushroom products.


Subject(s)
Odorants , Shiitake Mushrooms , Ultraviolet Rays , Volatile Organic Compounds , Shiitake Mushrooms/chemistry , Volatile Organic Compounds/analysis , Odorants/analysis , Ion Mobility Spectrometry/methods , Gas Chromatography-Mass Spectrometry/methods
20.
J Am Soc Mass Spectrom ; 35(4): 793-803, 2024 Apr 03.
Article in English | MEDLINE | ID: mdl-38469802

ABSTRACT

The opioid crisis in the United States is being fueled by the rapid emergence of new fentanyl analogs and precursors that can elude traditional library-based screening methods, which require data from known reference compounds. Since reference compounds are unavailable for new fentanyl analogs, we examined if fentanyls (fentanyl + fentanyl analogs) could be identified in a reference-free manner using a combination of electrospray ionization (ESI), high-resolution ion mobility (IM) spectrometry, high-resolution mass spectrometry (MS), and higher-energy collision-induced dissociation (MS/MS). We analyzed a mixture containing nine fentanyls and W-15 (a structurally similar molecule) and found that the protonated forms of all fentanyls exhibited two baseline-separated IM distributions that produced different MS/MS patterns. Upon fragmentation, both IM distributions of all fentanyls produced two high intensity fragments, resulting from amine site cleavages. The higher mobility distributions of all fentanyls also produced several low intensity fragments, but surprisingly, these same fragments exhibited much greater intensities in the lower mobility distributions. This observation demonstrates that many fragments of fentanyls predominantly originate from one of two different gas-phase structures (suggestive of protomers). Furthermore, increasing the water concentration in the ESI solution increased the intensity of the lower mobility distribution relative to the higher mobility distribution, which further supports that fentanyls exist as two gas-phase protomers. Our observations on the IM and MS/MS properties of fentanyls can be exploited to positively differentiate fentanyls from other compounds without requiring reference libraries and will hopefully assist first responders and law enforcement in combating new and emerging fentanyls.


Subject(s)
Fentanyl , Tandem Mass Spectrometry , Humans , Tandem Mass Spectrometry/methods , Protein Subunits , Ion Mobility Spectrometry/methods
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