Application Of GC/MS To Qualitative Analyses Of Some Drugs

Three rapid, sensitive and specific methods with gas chromatography-mass spectrometry were established for the qualitative analyses of some drugs. The methods were applied successfully to monitoring the synthetic process and analysis of natural products. It was attempted to resolve a series of problems involved in pharmaceutical analysis by means of the technique.1. Application to monitoring the synthetic processA mixture of synthetic products of brominated tetramethylpyrazine was analyzed by the gas chromatography-mass spectrometry. The possible fragmentation pathway of 2-bromomethyl-3, 5, 6-trimethylpyrazine, which was used to identify the structure of principal compounds, was proposed. The results showed that there were dibromo- and tribromo-substituted tetramethylpyrazines in the synthetic products besides the target compound 2-bromomethyl-3, 5, 6 -trimethylpyrazine.A mixture of synthetic products of brominated 1,4-bimethylbenzene was analyzed by the gas chromatography-mass spectrometry. The possible fragmentation pathway of 1, 4-bibromomethyl benzene, which was used to identify the structure of principal compounds, was proposed. The peak of l-bromomethyl-4-(1-bromo-1-chloromethyl) benzene indicated the bromine reagent was impurity.Combination of GC and MS could be used in qualitatively andquantitatively monitoring of synthetic process.2. Application to the assay of chemical component of essential oil of curcuma longa L.A GC/MS method was developed for analysis of chemical component of essential oil of curcuma longa L. from two extractions (ultrasonic extraction and steam distillation). It was found that same compounds were extracted by these two methods. A number of sesquiterpene ketone compounds such as ar-turmerone, a-turmerone, curlone, as well as a number of terpene compounds such as ar-curcumene, zingiberene were detected in the essential oil. The possible fragmentation pathways of the main compounds were proposed in this section.3. Application to analyses of chemical compounds of Citrus grandis (L.) OsbeckA GC/MS method was developed for analysis of main chemical component of seven different Citrus species. The results indicated that there was more essential oil in fruits originating from Huazhuo County, while more ergostenone, stigmastenone in fruits originating from Guangxi Province.