Quantitative 1H-NMR (qNMR) is a
well-established and highly reliable technique
for measuring the purity of reference standards. The core principal of qNMR is
straightforward: the intensity of a proton signal is directly proportional to
the number of resonant nuclei (spins)[1].
This method involves comparing the NMR
peak intensities of a compound to determine its concentration based on the
integral of the proton signals.
A critical step inqNMR experiment is selecting a appropriate internal standard.
Key considerations include:
• The internal standard should not chemically react with the target
substance.
• It should exhibit a suitable single peak width.
• Its signal peak must not overlap with those of the analyte.
For example, Bao-Ming Huang et al. measured the purity of Ginsenoside Rg1[1]
using qNMR for selecting potassium phthalate as the internal standard[2]. This
method is preferable to quantify reference standard when the chemical property
and the detection methods of the reference standard is uncertain.
Figure 1. The mixture of Rg1 reference substance and internal standard recorded
with methanol-d4[2].
MedChemExpress Popular Reference Standards Compounds
At MedChemExpress (MCE), we provide a wide range of high-quality reference
standards, each accompanied by comprehensive analysis documentations to verify
product structure, purity and content. All products are rigorously tested under
the ISO 9001/ ISO 17025 system, ensuring reliability and precision for your
research needs.
