A gas chromatographic method for the determination of methamidophos pesticide residues in the Allium Chinense was established by means of micro chemistry and solid phase extraction techniques.

The microanalytical method of elemental sulfur include chemical method and instrumental method such as Electrochemical analysis, Chromatography, XPS et.

GC was applied successfully to isolate and determine the trace ethanol in the lactic acid fermentation broth.