OBJECTIVETo develop a quick identification method for the sun-dried and sulfur-fumigated Angelicae Sinensis Radix used by Fourier transform infrared spectroscopy (FTIR) combined with second derivative infrared spectroscopy.

METHODThe alcoholic and aqueous extracts of sun-dried and sulfur-fumigated Angelicae Sinensis Radix were analyzed by using FTIR, the further analysis was used by second derivative infrared spectroscopy.

RESULTThere existed differences between their infrared spectra either extracted by ethanol or water, while the distinctions were more obvious after analyzing their alcoholic and aqueous extracts through high resolution of second derivative infrared spectroscopy. Infrared spectra showed that the absorption peaks of Angelicae Sinensis Radix were significantly reduced and a new absorption peak appeared after sulfur-fumigated process in alcoholic extracts, while both of them changed markedly in the "fingerprint region" ranging from 1 000 to 400 cm(-1) in aqueous extracts. Second derivative spectra showed that the absorption peaks of sulfur-fumigated Angelicae Sinensis Radix extracted by ethanol weakened and disappeared at about 3 578 cm(-1) and 3 541 cm(-1), while both of them differed significantly from each other ranging from 1 400 to 1 200 cm(-1) as well as 800 cm(-1) to 600 cm(-1), difference also existed between them extracted by water ranging from about 3 900 to 3 850 cm(-1) and 3 800 to 3 750 cm(-1).

CONCLUSIONThe FTIS method combined with second derivative can be utilized to distinguish sun-dried and sulfur-fumigated Angelicae Sinensis Radix efficiently, conveniently and accurately, and provide a basis for identification and quality control of Angelicae Sinensis Radix.