Quantification of a volatile deuterated compound by the differential scanning calorimetry combined with quantitative nuclear magnetic resonance and its verification by the mass balance method combined with gas chromatography-mass spectrometry

Differential scanning calorimetry (DSC) technology has been proven to be able to detect the purity of chemical reference substances, but there are few studies on its applicability to volatile organic compounds. In this study, the purity of a volatile deuterated compound (benzene-d 6 ) was successfully assessed by the DSC combined with quantitative nuclear magnetic resonance (qNMR), in which the qNMR determined the content of benzene (as an isotopic impurity). The result was verified by the mass balance method combined with gas chromatography-mass spectrometry (GC-MS), in which the GC-MS determined the content of benzene. The results showed that the purity value of benzene-d 6 was 994.1 mg g −1 ± 4.1 mg g −1 , at the 95% confidence interval, which is equivalent to the value of 994.8 mg g −1 ± 1.2 mg g −1 from the mass balance method combined with GC-MS. It was proved that the DSC combined with qNMR can be used to quantify the purity of volatile deuterated compounds. For volatile compounds without isotopic impurities, they can be directly quantified by DSC. It should be noted that volatile compounds must be fully solidified under low temperature conditions to ensure the reliability of the results. • The effectiveness of DSC combined with qNMR in assessing the purity of volatile deuterated compounds was confirmed. • The purity value of benzene-d 6 was equivalent to the value from the mass balance method combined with GC-MS. • The purity results of DSC for volatile compounds were reproducible at lower heating rates and lower freezing temperatures. • It was proved that DSC cannot distinguish isotopic compounds with the same structure.