Abstract
The possibility of determining the water content of cigarette smoke condensate by the absorption in the near infra-red is already known. The most promising of the methods hitherto published has been improved in an essential step. The smoke condensate is dissolved in tetrachloromethane containing 10 percent by volume of methanol. The differential absorbance of the smoke solution between the wave lengths 1.850 and 1.875 micron is proportional to its water content. The method has a precision of ± 0.5 mg of water (95 percent confidence limits) for a total amount of 10 to 50 mg of water per 25 ml of solution. The accuracy and specifity of the method are assured. The experimental variables are not critical - except the composition of the solvent which must be maintained accurately - and the analytical procedure is, therefore, rapid, reproducible and simple.