Abstract: The principles underlying selection of NMR acquisition parameters (i.e., relaxation delay time, pulse width and number of transient etc.) for quantitative analysis of drugs were discussed in detail. Some requirements on selecting appropriate peaks for quantitative analysis were proposed. We showed that the methyl peak is not suitable for quantitative analysis because it often has long relaxation time. With the principles discussed, the content of vitamin C determined by quantitative NMR analysis was found to have relative standard deviation less than 1%.

Key words: nuclear magnetic resonance, quantitative analysis, drug, acquisition parameter, vitamin C