Capillary Column-Gas Chromatographic Determination of Camphor,Menthol,Borneol and Isoborneol in Plaster of Traditional Chinese Medicines Using a Modified Soxhlet′s Extractor

A modified Soxhlet′s extractor was used in the capillary column gas-chromatographic determination of camphor,menthol,borneol and iso-borneol in plasters of traditional Chinese medicines,for extraction of the above mentioned compounds.It was shown that the efficiency of extraction of the modified Soxhlet′s extractor was raised about 40% as compared with the conventional model.Acetone was used as the extraction solvent.An aliquot of the extract was used for GC determination using naphthalene as internal standard.Data of linearity ranges obtained were as follows: ① for camphor: 21.28-1.915×103mg·L-1;② for menthol: 26.02-2.342×103mg·L-1;③ for borneol 7.9-7.11×102mg·L-1 and ④ for isoborneol: 4.42-397.8 mg·L-1.Tests for recovery and precision of the method using the modified extractor was performed,giving values of recovery in the range of 92.1%-99.5%,and values of RSD′s (n=7) in the range from 1.1% to 3.5%.