A5002111877- Vitamin D Research Studies
- Analytical Chemistry and Chromatography
- Mass Spectrometry Techniques and Applications
- Metabolomics and Mass Spectrometry Studies
- Microfluidic and Capillary Electrophoresis Applications
- Effects and risks of endocrine disrupting chemicals
- Vitamin C and Antioxidants Research
- Diet and metabolism studies
- Hormonal Regulation and Hypertension
- Biosensors and Analytical Detection
- Hormonal and reproductive studies
- Stress Responses and Cortisol
- Pharmacological Effects and Toxicity Studies
- Tryptophan and brain disorders
- Alzheimer's disease research and treatments
- Retinoids in leukemia and cellular processes
- Adrenal Hormones and Disorders
- Antioxidant Activity and Oxidative Stress
Humboldt-Universität zu Berlin
2019-2024
Saarland University
2014-2016
RATIONALE Isobaric interferences in human serum can potentially influence the measured concentration levels of 25‐hydroxyvitamin D [25(OH)D], when low resolving power liquid chromatography/tandem mass spectrometry (LC/MS/MS) instruments and non‐specific MS/MS product ions are employed for analysis. In this study, we provide a detailed characterization these technical solution to reduce associated systematic errors. METHODS Detailed electrospray ionization Fourier transform ion cyclotron...
The present study systematically compares the sensitivity and selectivity of analysis multiple vitamin D metabolites after chemical derivatization using different reagents for liquid chromatography-tandem mass spectrometry (LC-MS/MS). Generally, is applied to increase ionization efficiency, which particularly important very low abundant metabolites. Derivatization can also improve LC separation. A wide variety has been reported in recent years, but information on their relative performance...
One of the characteristics Alzheimer´s disease (AD) is an increased amyloid load and enhanced level reactive oxidative species (ROS). Vitamin E has known beneficial neuroprotective effects, previously, some studies suggested that vitamin associated with a reduced risk AD due to its antioxidative properties. However, epidemiological nutritional approaches treatment are controversial. Here, we investigate effect α-tocotrienol, which belongs group E, on AD-relevant processes in neuronal cell...
This study presents a detailed experimental investigation of charge isomers protonated 4-quinolone antibiotics molecules formed during electrospray ionization (ESI) with proposed dissociation mechanisms after collisional activation. Piperazinyl quinolones have been previously shown to exhibit erratic behavior tandem MS analyses biological samples, which originated from varying ratios two isomeric variants ESI. Here, combination ESI-collision-induced (CID), differential ion mobility...
This short application note describes a simple and automated assay for determination of 25-hydroxyvitamin D (25(OH)D) levels in very small volumes human serum. It utilizes commercial 96-well micro-extraction plates with 25(OH)D isotope calibration quality control kits. Separation was achieved using pentafluorophenyl liquid chromatography column followed by multiple reaction monitoring-based quantification on an electrospray triple quadrupole mass spectrometer. Emphasis placed providing that...
Vitamin D compounds are a group of secosteroids derived from cholesterol that vital for maintaining bone health in humans. Recent studies have shown extraskeletal effects vitamin D, involving metabolites such as the dihydroxylated D3 1,25-dihydroxyvitamin and 24,25-dihydroxyvitamin D3. Differentiation characterization these isomers by mass spectrometry can be challenging due to zero-mass difference minor structural differences between them. The usually require separation liquid...
The metabolism of vitamin D3 includes a parallel C-3 epimerization pathway—in addition to the standard metabolic processes for D3—reversing stereochemical configuration −OH group at carbon-3 (β→α). While biological function 3α epimer has not been elucidated yet, additional species cannot be neglected in analytical determination D3, as it potential introduce errors if properly accounted for. Recently, some inconsistent mass spectral behavior was seen 25-hydroxyvitamin (25(OH)D3) epimers...
We used electrospray ionization and ion mobility spectrometry-mass spectrometry to detect characterize the three anticancer drugs palbociclib, copanlisib, olaparib. Ion mobility-mass density functional theory revealed that these compounds generate isomers during (protomers) due presence of multiple protonation sites within their chemical structures. Our work has implications for understanding solution- gas-phase chemistry molecules spray-based processes.
In this study, we extended a previously developed one-pot double derivatization reaction to establish the first routine isotope-coded multiplex for vitamin D and its metabolites application in clinical environments, using commercial reagents, without need specialized reagents advanced synthesis requirements. The original process consisted of both Cookson-type reagent hydroxyl groups. Initially, analytes are derivatized by Diels-Alder 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), followed...