- Journal Details
- Format
- Journal
- eISSN
- 2719-9509
- First Published
- 01 Jan 1992
- Publication timeframe
- 4 times per year
- Languages
- English
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- Open Access
Comparative Investigation on the Measurement of Filter Efficiency: Results of an International Collaborative Investigation Carried out by the Coresta Smoke Technology Group / Vergleichsuntersuchung zur Ermittlung der Wirkung von Cigarettenfiltern: Ergebnisse einer Internationalen Ringuntersuchung durch die Arbeitsgruppe „Rauchanalytik“ der CORESTA
Page range: 1 - 35
Abstract
Various informations can be derived from the investigation on the measurement of filter efficiency which was carried out in cooperation of ten laboratories.
1.Weight of smoke condensates (wet and dry) and smoke alkaloids in mg per cigarette
a)Within each of the laboratories the dispersion of results can best be described by the coefficient of variation "within" the laboratories (standard deviation divided by mean, expressed as a percentage).
For the results obtained by using the CORESTA-standards the averages of this coefficient were as follows: condensate wet: 2.6 %; condensate dry: 2.3 %; alkaloids: 2.7 %.
In six laboratories a simplified method (without selection of cigarettes by weight and draw resistance) was used. Five of these laboratories obtained a wider dispersion of results while in the sixth the weights of total condensate were found to differ less from the mean. The CORESTA-standards are to be preferred for finer comparisons, while the simplified method can be accepted for routine estimation.
b)From the mean values obtained by the different laboratories for the same type of cigarette (comparable as to filter and tobacco) a coefficient of variation "between" laboratories can be calculated. For the measurements carried out according to CORESTA-standards, the averages of this coefficient were as follows: condensate wet: 8.3 %; condensate dry: 6.6 %; alkaloids: 11.0 %.
Approximately 30 % to 50 % of this dispersion between the laboratories can be explained by systematic deviations in details of the analytical procedures. These characteristic deviations are to be observed rather constantly in most of the measurements carried out on different types of cigarettes (differing by filter and tobacco).
2.Filter Efficiency
a)For measurements according to CORESTA-standards the coefficient of variation "within" the laboratories showed the following averages: condensate wet: 9.6 %; condensate dry: 6.7 %; alkaloids: 11.5 %. If the simplified method was applied in five of the laboratories this coefficient was found to be higher, while in the sixth of these laboratories no difference was observed.
b)The coefficient of variation "between" the laboratories (CORESTA-standards) had the following mean values: condensate wet: 15.0 %; condensate dry: 15.9 %; alkaloids: 17.5 %.
Even if due allowance is made for the known systematic deviations between the laboratories this dispersion cannot be reduced.
3.Comparison of two types of tobacco
Total condensates (wet and dry) and total smoke alkaloids per cigarette are found to be higher if tobacco 1 is used. This difference between the two tobaccos is shown in the plain cigarettes as well as in those with filter A or filter B. The average findings (10 laboratories, CORESTA-standards) were as follows: tobacco 1 - condensate wet: 41.1; condensate dry: 36.4; alkaloids: 2.64; tobacco 2 - condensate wet: 39.9; condensate dry: 34.4; alkaloids: 2.00.
4.Comparison of the two filters
Filter B is much more efficient than filter A as measured by the yields of condensates (wet and dry) and of alkaloids. The filter efficiency is practically not influenced by the use of the different tobaccos 1 or 2. The mean efficiency of the two filters (mean from tobaccos 1 and 2) is given below (CORESTA-method): filter A - condensate wet: 0.170; condensate dry: 0.187; alkaloids: 0.189; filter B - condensate wet: 0.338; condensate dry: 0.364; alkaloids: 0.347.
The filter efficiencies do not differ much, regardless whether they are measured by yield of wet or dry condensates or by yield of smoke alkaloids. With regard to draw resistance the two filters differ in the same sense but the difference is much smaller; filter A = 0.291; filter B = 0.350.
With each of the two filters tobacco 1 increases the draw resistance more than does tobacco 2.
5.Factors influencing the variability of results
The statistical analysis of the results obtained by one of the laboratories has shown that the yield of condensates and alkaloids per cigarette can vary considerably and systematically from one channel of the smoking machine to the other. Average amounts of smoke constituents should therefore only be calculated if all of the channels have received the same share of the cigarettes tested.
The estimation of filter efficiency was practically not influenced by the factor ''channel'' of the smoking machine.
It would be interesting to investigate whether the systematic divergencies of results which have been found between the laboratories can be attributed to detectable deviations in details of the analytical procedures.
- Open Access
A Vapour-Distillation Apparatus for Analyses of Nicotine in Tobacco and Tobacco Smoke Condensates as well as for the Determination of Total Nitrogen / Eine Wasserdampf-Destillationsapparatur zur Nikotinbestimmung in Tabaken und Rauchkondensaten sowie zur Gesamtstickstoffbestimmung
Page range: 37 - 38
Abstract
A modern vapour-distillation apparatus of versatile use is described which is suitable for serial analyses of nicotine in tobacco and tobacco smoke condensates as well as for the determination of total nitrogen. The construction allows to work quickly with smaller quantities, the cleaning is done automatically.
- Open Access
Determination of the Water Content of Cigarette Smoke Condensate by Near Infra-red Spectrophotometry / Bestimmung des im Rauchkondensat enthaltenen Wassers durch Spektrophotometrie im nahen Infrarot
Page range: 39 - 50
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.