Isotope-labeled compounds are increasingly used in isotope dilution mass spectrometry (IDMS) for the quantitative analysis of pesticides. The major advantage of using this technique is that the isotope-labeled compounds have nearly the same physical properties as their non-labeled counterpart analogs, and thus show identical behavior during the workup and sample preparation process. This helps in overcoming the problems of matrix effects generally encountered in the usual LC-MS/GC-MS analysis, potentially resulting in biased results. By spiking the sample before workup with its isotope labeled analog, the loss of analyte that leads to matrix effects can be determined and compensated.
Paclobutrazol-(phenyl-d4) is an isotope labeled analog of the triazole fungicide paclobutrazol, wherein the C-2, C-3, C-5, and C-6 phenyl protons are replaced by deuterium.