[Gas chromatographic determination of camphora, mentholum, isoborneol and borneol in Guanxingao].

Guanxingao is a kind of traditional Chinese rubber electuary medicine which is able to either cure or guard against coronary heart disease and angina pectoris. The contents of camphora, mentholum, isoborneol and borneol in Guanxingao are determined by gas chromatography. The purpose of the study is to detect and control the loss of the four volatile components through production and standing and to guarantee the curative effect. Chromatographic analysis was performed on a GC-4004 gas chromatograph(FID). The column was a 3 mm i.d. x 2 m stainless steel tube packed with 7% PEG-1500 on 100-110 mesh 102 non-silanized white support. The column and the FID temperatures were 115 degrees C and 180 degrees C respectively. H2 was the carrier gas, 30 mL/min. Internal standard method was used for the quantitative estimation with naphthalene as the internal standard. The linear ranges were at least within 50-450 mg/L (r = 0.9999, n = 4). The correction factors against naphthalene were 1.262-1.286 and the RSDs were 0.32%-1.5%(n = 12). The recoveries were 98.44%-101.9%. In comparison with the theoretical contents, the average loss percentages are 71.72% (camphora), 65.60% (mentholum) and 66.31% (isoborneol + borneol). The samples were pretreated by means of isothermal (35 degrees C) water-bath extraction with acetone for 6 times with four hours each.