Abstract:We report on modifications made to a Paul-type quadrupole ion trap mass spectrometer and discuss its application in infrared ion spectroscopy experiments. Main modifications involve optical access to the trapped ions and hardware and software coupling to a variety of infrared laser sources at the FELIX infrared free electron laser laboratory. In comparison to previously described infrared ion spectroscopy experiments at the FELIX laboratory, we find significant improvements in efficiency and sensitivity. Effec… Show more
“…Details of
the hardware modifications and of software operation have been previously
reported. 8,20 Collected HPLC fractions were directly electrosprayed
(+ESI) to produce IR/mass spectra. All reference measurements were
generated by +ESI from solutions of 10 –7 M in 50:50
MeOH/H 2 O.…”
Section: Methodsmentioning
confidence: 99%
“…4−7 Using the combination of state-of-the-art commercial ion trap mass
spectrometry platforms 8−10 with intense and tunable infrared lasers, such as
user facility-based free electron lasers (FELs) 11,12 and table top optical parametric oscillators, 13−15 an infrared
spectrum can be generated for ions at any m / z peak in a mass spectrum.…”
mentioning
confidence: 99%
“…8 This sensitivity thus enables the measurement
of IR spectra of ions that are components of collected HPLC fractions
by direct infusion electrospray ionization (ESI). Here, we demonstrate
the combination of HPLC and IR-IS and apply it for the identification
of molecular structures in the field of drug metabolism.…”
High-performance liquid chromatography
was used in combination
with infrared ion spectroscopy for the identification of positional
isomers of hydroxy-atorvastatins, the primary metabolites of the drug
atorvastatin. The results demonstrate the direct applicability of
infrared ion spectroscopy in the field of drug metabolism and, more
generally, its promising role in state-of-the-art analytical laboratories
for the identification of small molecules buried in complex mixtures.
In combination with chromatographic separation, infrared spectroscopy
of mass-selected ions provides a promising new route for the identification
of the molecular structures of unknown m/z peaks in a mass spectrum. We demonstrate that currently
existing experimental protocols allow the measurement of an IR spectrum
from less than 10 ng of sample obtained in a collected HPLC fraction.
“…Details of
the hardware modifications and of software operation have been previously
reported. 8,20 Collected HPLC fractions were directly electrosprayed
(+ESI) to produce IR/mass spectra. All reference measurements were
generated by +ESI from solutions of 10 –7 M in 50:50
MeOH/H 2 O.…”
Section: Methodsmentioning
confidence: 99%
“…4−7 Using the combination of state-of-the-art commercial ion trap mass
spectrometry platforms 8−10 with intense and tunable infrared lasers, such as
user facility-based free electron lasers (FELs) 11,12 and table top optical parametric oscillators, 13−15 an infrared
spectrum can be generated for ions at any m / z peak in a mass spectrum.…”
mentioning
confidence: 99%
“…8 This sensitivity thus enables the measurement
of IR spectra of ions that are components of collected HPLC fractions
by direct infusion electrospray ionization (ESI). Here, we demonstrate
the combination of HPLC and IR-IS and apply it for the identification
of molecular structures in the field of drug metabolism.…”
High-performance liquid chromatography
was used in combination
with infrared ion spectroscopy for the identification of positional
isomers of hydroxy-atorvastatins, the primary metabolites of the drug
atorvastatin. The results demonstrate the direct applicability of
infrared ion spectroscopy in the field of drug metabolism and, more
generally, its promising role in state-of-the-art analytical laboratories
for the identification of small molecules buried in complex mixtures.
In combination with chromatographic separation, infrared spectroscopy
of mass-selected ions provides a promising new route for the identification
of the molecular structures of unknown m/z peaks in a mass spectrum. We demonstrate that currently
existing experimental protocols allow the measurement of an IR spectrum
from less than 10 ng of sample obtained in a collected HPLC fraction.
“…Using a tuneable infrared laser such as the FELIX IR free electron laser 19, 23 , an IR spectrum can be generated for any m/z peak isolated from the mass spectrum. Here, we demonstrate the use of IR-IS to distinguish three N-acetylhexosamines directly from urine and cerebrospinal fluid (CSF) without any sample preparation (aside from dilution) or chromatographic separation.…”
Section: Introductionmentioning
confidence: 99%
“…1. This approach is largely enabled by recent advances in experimental sensitivity and efficiency that allow us to measure IR spectra for ions at concentrations down to the low nanomolar range, consuming less than <50 μL of solution per IR spectrum 23 . Although the N-acetylhexosamines discussed here cannot be separated by the standard HPLC protocols in our laboratory, this sensitivity and efficiency generally allows us to measure an IR spectrum of ions generated from a collected HPLC fraction.Figure 1Experimental approach of IR-IS, combining mass spectrometry with infrared spectroscopy for metabolite identification.…”
Small molecule identification is a continually expanding field of research and represents the core challenge in various areas of (bio)analytical science, including metabolomics. Here, we unequivocally differentiate enantiomeric N-acetylhexosamines in body fluids using infrared ion spectroscopy, providing orthogonal identification of molecular structure unavailable by standard liquid chromatography/high-resolution tandem mass spectrometry. These results illustrate the potential of infrared ion spectroscopy for the identification of small molecules from complex mixtures.
Uronic acids are important constituents of polysaccharides found on the cell membranes of different organisms. To prepare uronic-acid-containing oligosaccharides,u ronic acid 6,3-lactones can be employed as they displayaf ixed conformation and au nique reactivity and stereoselectivity. Herein, we report ah ighly b-selective and efficient mannosyl donor based on C-4 acetyl mannuronic acid 6,3-lactone donors.T he mechanism of glycosylation is established using ac ombination of techniques,i ncluding infrared ion spectroscopyc ombined with quantum-chemical calculations and variable-temperature nuclear magnetic resonance (VT NMR) spectroscopy. The role of these intermediates in glycosylation is assayed by varying the activation protocol and acceptor nucleophilicity.T he observed trends are analogous to the well-studied 4,6-benzylidene glycosides and mayb eu sed to guide the development of next-generation stereoselective glycosyl donors.
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