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ISO 21766:2018 pdf free

ISO 21766:2018 pdf free.Tobacco and tobacco products一Determination of tobacco-specific nitrosamines in tobacco products
Prepare seven working standard solutions that cover the concentration range of interest. Table 1 provides an example of calibration standard preparation.
The TSNA calibration standards are prepared in seven separate 100 ml volumetric flasks, each containing 10 ml of 100 mM ammonium acetate solution. Transfer 1,00 ml of the internal standard spiking solution (2 000 ng/ml) to each of the seven volumetric flasks. Next, add the appropriate volume of the mixed TSNA standard solution (I), given in Table 1. Then add the volume of acetonitrile, given in Table 1. Finally, dilute each of the seven flasks to volume with 100 mM ammonium acetate and mix well.
Calculate the exact concentrations for each standard and record.
NOTE Stock solutions of the individual TSNAs and deuterated internal standards in acetonitrile can be purchased at the required levels.
Depending on the TSNA concentration of the tobacco sample, the extract may require dilution in order to obtain a response covered by the calibration range. If no solid phase step is involved, the sample extracts could be diluted with extraction solution containing internal standard with the same concentration as in the sample extraction solution. A dilution factor of 10 is sufficient for most samples.
Alternatively, and always if a solid phase extraction step is involved, a lower sample weight can be used or the volume of extraction solution can be increased. When a larger volume of extraction solution is used, remember to increase the amount of internal standard as well in order to ensure that the response is in the calibration range; for example, if the volume of extraction solution is doubled, double the amount of internal standard as well. Increased extraction volume is preferred when portions of tobacco, e.g. pouches, are analysed. In all cases of dilution, remember to multiply the added dilution factor with the instrument test result.
In 2015, a collaborative study was conducted involving 14 laboratories[6]. This study included the analysis of the four CORESTA reference products. Results were evaluated in basic conformance with ISO 5725-2 and ISO/TR 22971.ISO 21766 pdf free download.

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