Gravimetric determination following extraction with n-hexane

Low-boiling substances are only recorded in part with this method in addition errors can also arise as a result of the co-extraction of surface-active substances and in some cases natural waxes, humic materials etc. [Pg.519]

Following extraction of the hydrocarbons with 1,1,2-trichlorotri-fluoroethane, measurements are carried out in the wavelength range from 3.2 to 3.6 pm. [Pg.519]

3 Measurement of UV fluorescence following separation by thin-layer chromatography [Pg.519]

The fluorescence spectrum is recorded following extraction with carbon tetrachloride. This method can be considered as augmenting the infrared intensity spectroscopy method. [Pg.519]

In this method of investigation, volatile organic compounds (e.g. fuels, organic solvents), which go over into the gas phase after the vapour pressure has reached equilibrium, are removed in gaseous form and subjected to analysis by gas chromatography. [Pg.519]

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