Iizuka, H; Morishita, M; Yajima, T; Katayanagi, M
The determination method of dl-camphor, l-menthol and methyl salicylate in medicated spirits was established by the use of steam carrier gas chromatography with an Ohkura gas chromatograph SSC-1/Model 701 equipped with a hydrogen flame ionization detector. A glass column, 2.2 mm i.d. and 1 m in length, packed with 60â80 mesh Neopack 1B coated with 10% polyethylene glycol 20 M (PEG20 M) was used. The column was used at a constant temperature of 135°C and an injector temperature was kept at 200°C. The carrier flow rate was that obtained by feeding water at a rate of 10 µl/min. Isopropyl carbamate was chosen as an internal standard for the simultaneous determination of the three components. Under the conditions employed, dl-camphor, l-menthol, isopropyl carbamate and methyl salicylate were eluted in this order within 15 min as sharp peaks with satisfactory resolution and reproducibility. Following results were obtained by the regression analyses of the weight ratio (X1, X2, X3) and the peak height ratio (Y1, Y2, Y3) between dl-camphor (X1, Y1), l-menthol (X2, Y2) or methyl salicylate (X3, Y3) and the internal standard: regression equations, Y1 = 4.136X1+0.0155, Y2 = 2.814X2 +0.099 and Y3 = 1.150X3 + 0.155; correlation coefficients, r1 = 0.998, r2 = 0.999 and r3 = 0.991; relative standard deviations after five runs were 0.67, 0.72 and 0.84% for Y1, Y2 and Y3, respectively. Under the chromatographic conditions mentioned above, two medicated spirits prepared as described in JPX and three commercial medicated spirits were successfully analysed quantitatively only with dilution without further pretreatment of samples. © 1986, The Japan Society for Analytical Chemistry. All rights reserved.