ISO 22980:2020 pdf download Tobacco — Determination of the content of total alkaloids as nicotine — Continuous-flow analysis method using KSCN/DCIC
6.2System wash solution
Add 1 ml of polyoxyethylene lauryl ether (5.1),30 % solution to about 800 ml water and mix. Thendilute to 1 000 ml with water.Do not store the solution longer than a week and use a clean bottle for thefresh solution.
6.35 % acetic acid solution
Add 50 ml of acetic acid to about 800 ml water and mix. Then dilute it to 1 000 ml with water. Do notstore the solution longer than a week and use a clean bottle for the fresh solution.
6.4Sampler wash solution
Use the extraction solution, water or 5 % acetic acid as sampler wash solution.6.5 Potassium thiocyanate solution
Dissolve 2,88 g of potassium thiocyanate (5.7z) in water. Dilute to 250 ml with water and mix well.6.6Sodium dichloroisocyanurate (DCIC) solution
Dissolve 2,20 g of sodium dichloroisocyanurate (5.8) and dilute to 250 ml with water. Prepare a freshsolution each day of measurement.
6.7Neutralisation solution A
Dissolve 1 g of citric acid monohydrate (5.11) and 10 g of ferrous sulfate in about 500 ml of water.Dilute to 1 000 ml with water and mix well.
6.Neutralisation solution B
Dissolve 10 g of sodium carbonate (5.9) in about 500 ml of water. Dilute to 1 000 ml with water andmix well.
6.9 Buffer solution A
Dissolve71,6 g of sodium phosphate dibasic dodecahydrate(5.3) and 11,76g of sodium citrate dihydrate(5.5) in about 500 ml of water. Dilute to 1 000 ml with water, add 1 ml of polyoxyethylene lauryi ether[5.1]).30 % solution mix thoroughly.
6.10 Buffer solution B
Dissolve 71,6 g of sodium phosphate dibasic dodecahydrate (5.3),6,2 g of sodium phosphate monobasicdihydrate (5.4),11,76 g of sodium citrate dihydrate (5.5) and 7,0 g of sulfanilic acid (5.6j in about 800 mlof water. Dilute to 1 000 ml with water, add 1 ml of polyoxyethylene lauryl ether (5.1),30 % solutionmix thoroughly.
7Preparation of standards7.1General
Check the purity of the nicotine ditartrate dihydrate (5.12) according to ISO 13276. The method canalso be standardized by using nicotine or other nicotine salts of known purity. In this case, an amountequivalent to the above used nicotine ditartrate dihydrate should be used.
7.2 Nicotine stock solution Weigh 3,75 g (to the nearest 0,000 1 g) of nicotine ditartrate dihydrate (5.12) in water and dilute to 500 ml in a volumetric flask. The solution contains approximately 2,5 mg nicotine per ml, store in a refrigerator at 0 °C to 4 °C. Before use, the nicotine stock solution stored at low temperature should be equilibrated to the working temperature. Prepare a fresh solution every month.
7.3 Working standards From the nicotine stock solution and extraction solution (water or 5 % acetic acid solution), prepare a series of at least 5 calibration solutions according to the nicotine concentration which is expected to be found in the test samples (e.g. a mass fraction of 0,5 % to 15 %). Calculate the exact concentration for each standard taking into account the purity of the nicotine ditartrate dihydrate (5.12). Store in a refrigerator at 0 °C to 4 °C. Before use, the working standards stored at low temperature should be equilibrated to the working temperature. Prepare fresh solutions every two weeks.
Apparatus
The laboratory needs the usual laboratory apparatus and, in particular, the following items.
8.1 Continuous-flow analyser, consisting of
— autosampler;
— peristaltic pump;
— chemistry manifold with dialyser and delay coils;
— photometric detector equipped with a 460 nm filter;
— data acquisition system or recorder.
See Figures A.1 and A.2 in Annex A for examples of suitable flow diagrams.
9 Procedure
9.1 Preparation of samples for analysis
Prepare the tobacco for analysis by grinding (the sample should totally pass a 1 mm sieve) and etermine the moisture content. If the tobacco is too wet for grinding it can be dried at a temperature not exceeding 40 °C.
9.2 Test portion
Weigh to the nearest 0,1 mg, approximately 250 mg, of the ground tobacco into a 50 ml conical flask.Add 25 ml of the extraction solution (water or 5 % acetic acid solution). Stopper and shake for about 30 min at about 150 r/min.ISO 22980:2020 pdf download