NMR has won its reputation as a powerful tool in qualitative analysis to determine the identity of compounds. Nowadays, however, the successful application of NMR in precise quantification determination of individual analysts and multicomponent analysis has also been explored. Creative Biostructure has developed a quantitative analytical system by NMR to provide services such as metabolites analysis, chemicals concentration determination, plastics processing, and drug impurity analysis.
Figure 1. Outline of the quantitative analysis suite.
Quantitative NMR, also known as qNMR, is an alternative to chromatography techniques for quantitative analysis due to multiple advantages. It is particularly suitable for simultaneous determination of the percentage of active compounds in organic chemicals such as pharmaceuticals, agrochemicals, and natural products. The method depends on the comparison of NMR signal intensities of the compounds of interest with reference signals. In the case of quality control, the signal of the main compound can be used as a reference. Both internal and external references could be applied to quantitative analysis by NMR. For internal calibration, a defined amount of reference materials is added to the sample solution. A calibration curve with different analyte concentrations can be used for external calibration. Hydrogen is highly abundant, especially in biological systems, and it is the most sensitive nucleus to NMR signal. 1H NMR produces narrow chemical shift with sharp signals, which is perfect for fast acquisition of quantitative results. In addition to 1H NMR, 13C, 19F, and 31P NMR are also applied to quantitative analysis.
Advantages of qNMR
The precision of qNMR plays a very important role as a quantitative method. Some physic-chemical properties such as solubility of the analyte, pH of sample, ionic strength between analyte and solvent may affect qNMR analysis, therefore, reference selection, data collection and interpretation for qNMR require experience from NMR specialists. Fell feel to contact us for detailed inquiry.