IS 5182 Pt.17-1979

标准号：IS 5182 Pt.17-1979
发布日期：1980/2/1 12:00:00
实施日期：1999/12/31 12:00:00
适用范围：1.1 This standard prescribes the method of measurement of the concentration of individual C1 to C5 hydrocarbons in the atmosphere. The lower limit of measurement is 0·01 parts per million ( ppm ) by volume ( that is, 0·01υl/l.). For analysis without concentration of the sample, the elution of the 17 hydrocarbons as given in Table 1 is accomplished within approximately 16 minutes. Hydrocarbons of higher molecular mass than C5 may bemeasured by concentration of the air sample.1.2 The lower limit of measurement of the C3 to C5 hydrocarbons may be extended to 0·1 parts per billion ( ppb ) by concentrating 100 ml of gas sample in a freeze trap. Methane is not collected quantitatively in the freeze-trap and the resolution of ethane and ethylene chromatographic peaks is reduced in the concentrated sample.