Analytical Instrument Documents

JEOL Resources


Documentation in support of your JEOL product.

Determination of Phenylalanine Isotope Ratio Enrichment by LC/Time-of-Flight Mass Spectrometry


Time-of-flight mass spectrometry has the advantages of high resolution, high sensitivity, and high mass accuracy but with relatively narrow dynamic range if a TDC (Time-to-Digital Converter) is used as a data acquisition system. This disadvantage of narrow dynamic range hinders the applications for isotope ratio enrichment measurement. Recently, a new LC/TOF-MS system was introduced that achieved a wide dynamic range by using an ADC (Analog-to-Digital Converter) instead of a conventional TDC. We used this system to evaluate the measurement of phenylalanine (Phe) isotope ratio enrichment. The accuracy, reproducibility, and sensitivity for the method were determined. The method is simple, rapid, and accurate and presents an attractive alternative to traditional GC/MS applications.


The system included an Agilent 1100 HPLC and a JEOL AccuTOF™ time-of-flight mass spectrometry system. Complete system control and data evaluation were carried out using a JEOL MassCenter™ workstation.

All solvents used were of HPLC grade. The standard solutions were prepared by mixing unlabelled Phe and 13C6-Phe in 0.1 % formic acid solution to make solutions with isotope ratio enrichments ranging from 0.02 % to 9.2 and a constant total concentration of 100 nmol/mL. The isotope ratio enrichment was expressed as tracer/tracee ratio (TTR).

Attached Files
Showing 0 Comment

Comments are closed.

Other Resources

Walkup NMR
  • See how the Delta NMR software allows users to just "walk up" and start NMR experiments
  • Mass Spec Reference Data
  • View our page of useful molecular references for Mass Spec
  • Tutorials (Mass Spec)
  • Documents on the basics of mass spectrometry
  • Delta NMR software Tutorials
  • Videos on how to use the Delta NMR software
  • No-D NMR
  • Description of No-D NMR and how it can be used to eliminate the need for deuterated solvents
  • Non Uniform Sampling (NUS)
  • Description of how NUS is used to greatly reduce the time needed for running NMR experiments
  • NMR Basics
  • Overview of the Basics of NMR Theory
  • NMR Magnet Destruction
  • See our presentation of the slicing open of a JEOL Delta-GSX 270 MHz NMR Magnet
  • NMR Training
    Basic Operations and System Management for JEOL NMR Users
    Mass Spec Training
    Learn more about spectrometer operation and maintenance, data collection and processing, and advanced MS software operation.
    JEOLink NMR Newsletter
    We publish and send out this NMR newsletter to our customers. They can also be viewed here.
    Mass Media Newsletter
    We publish and send out this Mass Spec newsletter to our customers. They can also be viewed here.
    © Copyright 2024 by JEOL USA, Inc.
    Terms of Use
    Privacy Policy
    Cookie Preferences