Papers by Jan Claereboudt
Bioanalysis, Mar 1, 2015
An ultrasensitive nano UHPLC-ESI-MS/MS method is developed to simultaneously monitor three low-co... more An ultrasensitive nano UHPLC-ESI-MS/MS method is developed to simultaneously monitor three low-concentration neuromedin-like peptides in microdialysates. Peptide preconcentration and sample desalting is performed online on a trap column. A shallow gradient slope at 300 nl/min on the analytical column maintained at 35°C, followed by two saw-tooth column wash cycles, results in the highest sensitivity and the lowest carryover. The validated method allows the accurate and precise quantification of 0.5 pM neurotensin and neuromedin N (2.5 amol on column), and of 3.0 pM neuromedin B (15.0 amol on column) in in vivo microdialysates without the use of internal standards. The assay is an important tool for elucidating the role of these neuromedin-like peptides in the pathophysiology of neurological disorders.
Rapid Communications in Mass Spectrometry, 2001
In this study a new method for the simultaneous confirmation of betamethasone and dexamethasone r... more In this study a new method for the simultaneous confirmation of betamethasone and dexamethasone residues in bovine liver is presented. A Quattro LCZ triple quadrupole mass spectrometer, equipped with an atmospheric pressure ionization (API) source, was coupled to a high performance liquid chromatograph (HPLC) system. Spiked liver samples were first extracted with acetonitrile, and the extracts were purified on C‐18 columns. LC separations were performed on a Hypercarb column, with acetonitrile/water (90:10, v/v, +0.3% formic acid) as the mobile phase. Retention times for dexa‐ and betamethasone were 6.60 and 8.50 min, respectively. Fluorometholone had a retention time of 6.70 min and was used as the internal standard. The detection of the analytes was performed in the multiple reaction monitoring (MRM) mode. The assay was linear over the range of 0.5 to 8 µg/kg for both analytes. The estimated determination limits were 0.2 µg/kg for both beta‐ and dexamethasone and the quantification limits were 0.4 µg/kg for dexamethasone and 0.3 µg/kg for betamethasone. Analysis precision at 1, 2 and 4 µg/kg was lower than 6.1% (relative standard deviation, RSD) and accuracy was at least 97.5%. Recoveries at 1, 2 and 4 µg/kg ranged between 56 and 69%. Copyright © 2001 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry, Feb 29, 2000
A novel, sensitive, high performance liquid chromatography/tandem mass spectrometric (i.e. mass s... more A novel, sensitive, high performance liquid chromatography/tandem mass spectrometric (i.e. mass spectrometry/mass spectrometry) method with on-line extraction and clean-up for the screening and confirmation of residues of tetracyclines in kidney has been developed. After liquid extraction of homogenised kidney with McIlvain buffer, an aliquot of the extract is directly injected on the LC/MS/MS system with further extraction and clean-up of the sample on-line. Detection of the analytes was achieved by positive electrospray ionization followed by multiple reaction monitoring. For each tetracycline the collisional decomposition of the protonated molecule to a unique, abundant fragment ion was monitored. The method has been validated for tetracycline, oxytetracycline, chlortetracycline and doxycycline. Calibration curves resulting from spiked blank kidney samples at the 100-1200 microgram/kg level showed good linear correlation. At the level of 600 microgram/kg both within- and between-day precision, as measured by relative standard deviation (RSD), were less than 7%. The limits of detection (LODs) for tetracycline, oxytetracycline, chlortetracycline and doxycyline were 18, 23, 24 and 21 microgram/kg, respectively. The limits of quantification (LOQs) for tetracycline, oxytetracycline, chlortetracycline and doxycyline were 36, 46, 47 and 42 microgram/kg, respectively. The recoveries ranged from 71 to 91%. The procedure provides a rapid, reliable and sensitive method for the determination of residues of tetracyclines in bovine kidney. The advantage of this method over existing methods is its decreased sample preparation and analysis time, which makes the method more suitable for routine analysis.
Drug Testing and Analysis, May 28, 2015
profiling of Internet-obtained Cerebrolysin using high performance liquid chromatographyelectrosp... more profiling of Internet-obtained Cerebrolysin using high performance liquid chromatographyelectrospray ionization ion trap and ultra high performance liquid chromatography-ion mobility-quadrupole time of flight mass spectrometry.
profiling of Internet-obtained Cerebrolysin using high performance liquid chromatographyelectrosp... more profiling of Internet-obtained Cerebrolysin using high performance liquid chromatographyelectrospray ionization ion trap and ultra high performance liquid chromatography-ion mobility-quadrupole time of flight mass spectrometry.
Analytical Chemistry, Dec 9, 2022
14th International Symposium on Hyphenated Techniques in Chromatography and Separation Technology (HTC-14), 2016
Rising population density and global mobility are among the reasons why pathogens such as SARS-Co... more Rising population density and global mobility are among the reasons why pathogens such as SARS-CoV-2, the virus that causes COVID-19, spread so rapidly across the globe. The policy response to such pandemics will always have to include accurate monitoring of the spread, as this provides one of the few alternatives to total lockdown. However, COVID-19 diagnosis is currently performed almost exclusively by Reverse Transcription Polymerase Chain Reaction (RT-PCR). Although this is efficient, automatable and acceptably cheap, reliance on one type of technology comes with serious caveats, as illustrated by recurring reagent and test shortages. We therefore developed an alternative diagnostic test that detects proteolytically digested SARS-CoV-2 proteins using Mass Spectrometry (MS). We established the Cov-MS consortium, consisting of fifteen academic labs and several industrial partners to increase applicability, accessibility, sensitivity and robustness of this kind of SARS-CoV-2 detect...
Travelling wave ion mobility spectrometry - mass spectrometry (TWIMS-MS) was evaluated as a tool ... more Travelling wave ion mobility spectrometry - mass spectrometry (TWIMS-MS) was evaluated as a tool for structural identification of metabolites of small molecule drugs in cases where the exact position of the biotransformation could not be identified by conventional tandem mass spectrometry. Test sets of compounds containing biotransformations at aromatic positions were analyzed. These present a problem for traditional MS methods since an atomic level localization of the biotransformation cannot normally be determined from MS(n) spectra. In addition to ion mobility measurements of the intact metabolite ions, ion mobility measurements of product ions were also made and the results compared with calculated values. This approach reduces the complexity of the problem, making theoretical calculations easier and more predictable when a modeled collision cross section (CCS) is required. A good relative correspondence between theoretical and measured CCSs was obtained allowing the identification of the exact position of the biotransformation. It was also demonstrated that authentic standards with substructures identical to those in the unknown can be used to assign the exact position of the biotransformation. In this approach the identification was based on the comparison of the drift times or CCSs for product ions of the standard, with those of the same product ions in the unknown.
Rapid Communications in Mass Spectrometry, 2000
A novel, sensitive, high performance liquid chromatography/tandem mass spectrometric (i.e. mass s... more A novel, sensitive, high performance liquid chromatography/tandem mass spectrometric (i.e. mass spectrometry/mass spectrometry) method with on-line extraction and clean-up for the screening and confirmation of residues of tetracyclines in kidney has been developed. After liquid extraction of homogenised kidney with McIlvain buffer, an aliquot of the extract is directly injected on the LC/MS/MS system with further extraction and clean-up of the sample on-line. Detection of the analytes was achieved by positive electrospray ionization followed by multiple reaction monitoring. For each tetracycline the collisional decomposition of the protonated molecule to a unique, abundant fragment ion was monitored. The method has been validated for tetracycline, oxytetracycline, chlortetracycline and doxycycline. Calibration curves resulting from spiked blank kidney samples at the 100-1200 microgram/kg level showed good linear correlation. At the level of 600 microgram/kg both within- and between-...
International Journal of Mass Spectrometry and Ion Processes
... reserved. Fast atom bombardment and tandem mass spectrometry for the characterization of hemo... more ... reserved. Fast atom bombardment and tandem mass spectrometry for the characterization of hemoglobin variants including a new variant. ...
Rising population density and global mobility are among the reasons why pathogens such as SARS-Co... more Rising population density and global mobility are among the reasons why pathogens such as SARS-CoV-2, the virus that causes COVID-19, spread so rapidly across the globe. The policy response to such pandemics will always have to include accurate monitoring of the spread, as this provides one of the few alternatives to total lockdown. However, COVID-19 diagnosis is currently performed almost exclusively by reverse transcription polymerase chain reaction (RT-PCR). Although this is efficient, automatable, and acceptably cheap, reliance on one type of technology comes with serious caveats, as illustrated by recurring reagent and test shortages. We therefore developed an alternative diagnostic test that detects proteolytically digested SARS-CoV-2 proteins using mass spectrometry (MS). We established the Cov-MS consortium, consisting of 15 academic laboratories and several industrial partners to increase applicability, accessibility, sensitivity, and robustness of this kind of SARS-CoV-2 detection. This, in turn, gave rise to the Cov-MS Digital Incubator that allows other laboratories to join the effort, navigate, and share their optimizations and translate the assay into their clinic. As this test relies on viral proteins instead of RNA, it provides an orthogonal and complementary approach to RT-PCR using other reagents that are relatively inexpensive and widely available, as well as orthogonally skilled personnel and different instruments. Data are available via ProteomeXchange with identifier PXD022550.
Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, 2003
Uploads
Papers by Jan Claereboudt