ISO 13276-2020 pdf free.Tobacco and tobacco products—Determination of nicotine purity-Gravimetric method usingtungstosilicic acid.
This document specifies a method for the gravimetric determination of the purity of nicotine usingtungstosilicic acid.
The method is applicable to pure nicotine or nicotine salts used to calibrate analytical methods for thedetermination of nicotine in the field of tobacco, tobacco products and smoke analysis.
Normative references:There are no normative references in this document.
Terms and definitions:No terms and definitions are listed in this document.
Complex formation of nicotine or its salts with tungstosilicic acid to form insoluble nicotinesilicotungstate.Determination of the precipitate mass by filtration using either a sintered glass cruciblein combination with oven-drying or an ashless filter paper in combination with incineration.
Use only reagents of recognized analytical reagent grade and distilled water or water of at leastequivalent purity.
5.1Tungstosilicic acid solution (CAS of tungstosilicic acid: 12027-43-9).
Dissolve 12 g of dodeca-tungstosilicic acid (H4[Si(W3010)4]·xH20) in 100 ml of water.
Avoid the use of the other forms of tungstosilicic acid such as 4H,0-Si0,10WO-3H,0 or4H,O-Si0,12WO,-20H,0 as they do not yield crystalline precipitates with nicotine.Tungstosilicic acidof the CAS 11130-20-4 and 12027-38-2 may be used for this method provided sufficiently crystallineprecipitation occurs.
Dry each glass filter crucible (6.6.1) in the oven (6.6.4) at (120±5)°C to constant mass (±1 mg). Store inthe desiccator (6.5).
Weigh, to the nearest 0,000 1 g, each glass crucible (6.6.1)[m, ) and filter the precipitate directly intothe glass filter using the Buchner flask(6.6.2) and vacuum source (6.6.3).Ensure that the precipitateis removed from the sides of the beaker and the glass stirring rod by washing into the filter withhydrochloric acid solution (5.3) approximately three times using 15 ml each. Discard the washings.Rinse with a further aliquot portion of hydrochloric acid solution (5.3)(up to 400 ml may be required)which should be collected and tested with a few drops of nicotine solution (5.4) to ensure that noopalescence occurs, i.e.all tungstosilicic acid has been removed.
Dry each glass crucible and precipitate in the oven (6.6.4) for 3 h at (120 ±5)°C.Allow to cool in thedesiccator and weigh to the nearest 0,000 1 g(m,).Place the filters back in the oven for 1 h, allow to cooland reweigh.Repeat, if necessary, until a constant mass (±1 mg) is obtained.
Filter the precipitate directly onto an ashless filter paper (6.7.1).Ensure that the precipitate is removedfrom the sides of the beaker and the stirring rod by washing into the filter with hydrochloric acidsolution (5.3) approximately three times using 15 ml each. Discard the washings.
Rinse with a further aliquot portion of hydrochloric acid solution (5.3)(up to 400 ml may be required)which should be collected and tested with a few drops of nicotine solution (5.4) to ensure that noopalescence occurs, i.e.all tungstosilicic acid has been removed.
Dry each crucible (6.7.2) on the Bunsen burner(6.7.3) or in the furnace(6.7.4) at 600 °C until constantmass (1 mg). Store in the desiccator (6.5).
Weigh, to the nearest 0,000 1 g, each crucible(6.7.2)(m ). Transfer the filter paper with the precipitateto the crucible. Place the crucible on a silica triangle resting on a tripod, heat gently at first and thenignite with the Bunsen burner (6.7.3). The crucible contents have to be broken up very carefully toensure complete removal of the carbon. The final residue should be greenish/yellow in colour. ISO 13276 pdf download.