a rapid, specific and accurate proton quantitative nuclear magnetic resonance spectroscopic (1h qnmr) and also a reversed phase derivatization hplc method have been developed to quantify a toxic, uv-visible inactive and non-volatile impurity n,n-dimethylamine hydrochloride (dma∙hcl) in metformin hydrochloride (mf∙hcl), an active pharmaceutical ingradient. the method is based on proton quantitat...

The baijiu spirit is often the focus of fraudulent activity due to widely varying prices products. In this work, Solid Phase Microextraction Gas Chromatography (SPME GCMS), Fourier Transform Infrared (FTIR) Spectroscopy and 1H qNMR spectroscopy were evaluated as potential methods authenticate samples. Data collected for 30 samples produced by seven different distilleries. data from SPME GCMS FT...

Quantitative nuclear magnetic resonance is a powerful tool in drug analysis because of its speed, precision, and efficiency. In present study, the application of variable temperature proton quantitative nuclear magnetic resonance (VT-1H-qNMR) for the calibration of three C-glycosylflavones including orientin, isoorientin, and schaftoside as reference substances was reported. Since there was con...

Mogroside V is one of the characteristic and effective components luohanguo extract, a food additive used as sweetener in Japan per Japan’s Standards Specifications for Food Additives (JSFA; 9th ed.). JSFA stipulates that quantitative determination mogroside content extract applies HPLC using analytical standard V. However, no reagents with proven purities are commercially available. Therefore ...

Quantitative nuclear magnetic resonance (qNMR) spectroscopy is employed by an increasing number of analytical and industrial laboratories for the assignment of content and quantitative determination of impurities. Within the last few years, it was demonstrated that (1)H qNMR can be performed with high accuracy leading to measurement uncertainties below 1 % relative. It was even demonstrated tha...

Quantitative NMR spectroscopy (qNMR) is an essential tool in organic chemistry, with applications including reaction monitoring, mechanistic analysis, and purity determination. Establishing the correct acquisition rate for consecutive qNMR scans requires knowledge of longitudinal relaxation time constants (T1) all nuclei being monitored. We report a simple method that about 10-fold faster than ...

Synthetic cathinones are a type of new psychoactive substances (NPS) that have been seriously abused. Owing to the rapid variation in their structures, absence reference standards poses challenge quantitative investigations. In this study, 1H nuclear magnetic resonance (1H qNMR) method was established using maleic acid as internal standard and shared signal (i.e., methylidyne hydrogen) on paren...

Quantitative nuclear magnetic resonance (qNMR) is a powerful tool in measuring drug content because of its high speed, sensitivity, and precision. Most of the reports were based on proton qNMR ((1)H qNMR) and only a few fluorine qNMR ((19)F qNMR) were reported. No research has been conducted to directly compare the advantage and disadvantage between these two methods. In the present study, both...