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. |
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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. |
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MedChemExpress Products |
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| References: |
[1] Journal of Pharmaceutical & Biomedical Analysis,
2005, 38(5):813-823.
[2] J Pharm Biomed Anal,
2017, 139:193-204. |
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