इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 9379 (2008): Tobacco and tobacco products -Method for determination of water content - Karl fischer method [FAD 4: Tobacco and Tobacco Products] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 9379:2008 ISO 6488:2004 W-F?7RTW’-6Z5 a-w-l-qm@mnqEp—m—l -q--l-dahmm–Taam– Indian Standard TOBACCO AND TOBACCO PRODUCTS — DETERMINATION OF WATER CONTENT — KARL FISCHER METHOD ( Third Revision) ICS 65.160 @ BIS 2008 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 ~U/j/ 2008 Price Group 4 Tobacco and Tobacco Products Sectional Commktee. FAD 4 NATIONAL FOREWORD This Indian Standard (Third Revision) which is identical with ISO 6488:2004 ‘Tobacco and tobacco products — Determination of water content — Karl Fischer method’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Tobacco and Tobacco Products Sectional Committee and approval of the Food and Agriculture Division Council. This standard was first published in 1977 subsequently revised in 1989 and 1999. The third revision of this standard is being brought about to align it with the latest edition of ISO 6488:2004 under dual numbering. The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following: a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’. b) Comma(,) has been used as adecimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker. Inthis adopted standard, reference appears to certain International Standards for which Indian Standards also exist. The corresponding Indian, Standards which are to be substituted in their respective places are listed below along with their degree of equivalence for the editions indicated: International Standard Corresponding Indian Standard Degree of Equivalence ISO 648 : 1977 Laboratory IS 1117: 1975 Specification for one-mark Technically glassware — One-mark pipettes pipettes (first revision) Equivalent ISO 3696:1987 Water for analytical IS 1070 : 1992 Reagent grade water — .40 laboratory use — Specification and Specification (third revision) test methods ISO 4874 : 2000 Tobacco — IS 8600 : 2007 Tobacco — Sampling of Identical Sampling of batches of raw material batches of raw material — General — General principles principles (second revision) ISO 8243 : 2006 Cigarettes — IS 12942 : 2007 Cigarettes — Sampling do Sampling (second revision) The technical committee responsible for the preparation of this standard has reviewed the provisions of the following International Standards and has decided that they are acceptable for use in conjunction with this standard: International Standard Title ISO 10362-2:1994 Cigarettes — Determination of water in smoke condensates — Part 2: Karl Fischer method ISO 15592-1:2001 Fine-cut tobacco and smoking articles made from it — Methods of sampling, conditioning and analysis — Part 1: Sampling In reporting the result of a test or analysis made in accordance with this standard, if the fins! value, observed or calculated, is to be rounded off, it shall be done in accordance with IS 2:1960 ‘Rules for rounding off numerical values (revised)’. IS 9379:2008 ISO 6488:2004 Indian Standard TOBACCO AND TOBACCO PRODUCTS — DETERMINATION OF WATER CONTENT — KARL FISCHER METHOD ( Third Revision) 1 Scope This International Standard specifies a method for the determination of water content by the Karl Fischer method. It is applicable to raw tobacco as well as tobacco taken from finished products. The method is suitable for water contents ranging from a mass fraction of at least 2 ‘A to 55 ‘A. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 648, Laboratory glassware — One-mark pipettes ISO 3696, Water for analytical laborato~ use— Specification and test methods ISO 4874, Tobacco — Sampling ofbatches ofraw material — General principles ISO 8243, Cigarettes — Sampling ISO 10362-2, Cigarettes — Determination ofwater in smoke condensates — Part 2: Karl Fischer method ISO 15592-1, Fine-cut tobacco and smoking articles made from it— Methods of sampling, conditioning and analysis — Part 1:Sampling 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 high-moisture tobacco any tobacco sample containing volatile matter over 20 Y. as determined by drying at between 100 “C and 105 “c 4 Principle The water content of a sample of tobacco or a tobacco product is determined by extraction of water by shaking the sample with dry methanol, followed by injection of an aliquot portion into the titration vessel, titration with pyridine-free Karl Fischer reagent and calculation of the water content. The method is applicable to any type of tobacco sample provided that the particle size reduction is less than 4 mm. NOTE If a size reduction (grinding or cutting) is applied, it can create a decrease in the original water content. Cryogenic techniques maybe usedto prevent suchmoisture losses. 1 1! IS 9379:2008 ISO 6488:2004 5 Reagents Use only reagents of recognized analytical grade 5.1 Karl Fischer reagent, free from pyridine, having a water equivalent per millilitre of reagent of approximately 2 mg to 5 mg. 5.2 Methanol, with a water content of less than 0,05 g per 100 g, This is hydroscopic so it is recommended to cap the bottle with an automatic delivery pipette equipped with drying tube. WARNING — Methanol is hazardous to human subjects and to the environment. Handle itwith care. 5.3 Desiccant, silica gel, freshly activated. 5.4 Water, complying with grade 2 of ISO 3696, or better 6 Apparatus Usual laboratory apparatus and, in particular, the following items All glassware used in the preparation and in the water determination shall be heated at (105 i 5) ‘C for at least 1h after visible water has evaporated. The glassware shall then be cooled and stored in a desiccator over desiccant (5.3) until used. 6.1 Karl Fischer apparatus for automatic titration, consisting of items 6.1.1 to 6,1.5. 6.1.1 Apparatus for the detection of the titration endpoint, according to the biamperiometrical method, 6.1.2 Double electrode, made of platinum. 6.1.3 Magnetic stirrer. 6.1.4 Titration vessel, 6.1.5 Automatic burettes, for methanol and Karl Fischer reagent. 6.2 Mechanical shaker, rotary platform, adjustable to a shaking frequency of 155 min-~. 6.3 Microsyringe, for the determination of the water equivalent, of capacity 50 p!, 6.4 One-mark pipettes, of capacities 10 ml and 20 ml, complying with Class A of ISO 648 6.5 Conical flasks, of capacities 250 ml and 500 ml, with a conical ground glass joint. 6.6 Hot-air oven, capable of maintaining a temperature of (105+5) ‘C 7 Standardization of the Karl Fischer reagent Add sufficient methanol (5.2) to the titration vessel (6.1.4) to immerse the tips of the electrodes. Titrate any residual solution (see Note) in the titration vessel to its endpoint by addition of Karl Fischer reagent (5.1). 2 IS 9379:2008 ISO 6488:2004 Add 50 PI of water to the titration vessel using the microsyringe (6,3). To ensure that the syringe does not contain air bubbles, fill it to above the 50 PImark, invert it and tap the air bubbles to the top. Then depress the plunger to the 50 PImark and remove excess water quickly from the needle tip with a tissue, As an alternative, fill the syringe with 50 PIof water and weigh the syringe. After dosage, weigh the syringe again and note the exact mass of water, Transfer the 50 PI of water to the titration vessel, taking care to inject the water directly into the solution, not allowing any to fall onto the neck or walls of the vessel. Where the vessel can be fitted with a rubber membrane cap, this shall be used and the needle inserted through the cap. If a water droplet remains on the needle tip, remove it by touching the surface of the solution in the vessel. Titrate with Karl Fischer reagent (5.1) and record the titration value. Repeat the process. If the difference between the values of two determinations is not greater than 0,05 ml, take the mean of two determinations. Otherwise repeat the whole determination. Standardize the Karl Fischer reagent every working day For best results with the Karl Fischer technique, it is important to ensure that all stages of the analysis are carried out in a uniform manner, extract to extract, sample to sample, day to day. NOTE ItiaGommonpradi~e with thedired titration technique toGarryout atitration “on top” of residual solution in the titration vessel, i. e. without removing the residual solution. When the volume in the vessel reaches a certain level, the liquid is run to waste, retaining just enough for the electrode tips to be immersed, In time, however, the methanol concentration in the vessel falls to a level such that the reaction cannot proceed satisfactorily. A precipitate may form and false titration values may be obtained. Only experience will tell when titration ‘(ontop or residual solution has reached this point and then the titration vessel has to be completely emptied to waste, rinsed, and recharged with methanol. Calculate the water equivalent of the Karl Fischer reagent according to the following equation: ~ – nlw (1) I’w where E isthe water equivalent, in milligrams of water per millilitre of reagent; I?lw isthe mass, in milligrams, of the water used for the standardization of the Karl Fischer reagent; [‘w isthe mean volume, in millilitres, of the Karl Fischer reagent used for the titration. Repeat the determination of the water equivalent daily and on each new batch of Karl Fischer reagent, 8 Sampling Sample raw tobacco in accordance with ISO 4874 and cigarettes in accordance with ISO 8243. Sample fine- cut tobacco in accordance with ISO 15592-1. Each time a sample is collected and stored, it should be placed in an airtight container having a size just sufficient to contain the sample. Ifsamples are stored at 4 ‘C, allow the closed container to equilibrate at room temperature before opening. 3 IS 9379:2008 ISO 6488:2004 9 Procedure 9.1 Sample handling Combine and mix enough retail units to constitute at least 100 g for each test subsample, If size reduction is employed, the sample should be cut sufficiently to pass through a 4 mm screen. The sample may be frozen with liquid nitrogen before cutting if the absolute moisture level is of interest. Cut filler from cigarettes need not be reduced further in size. If high-moisture samples (see 3.1) cannot be analysed immediately, they should be stored below 4 “C for no longer than 10 days. 9.2 Test portion 9.2.1 Take a test portion of about 5 g from the sample that has been prepared according to 9,1. Weigh to the nearest 0,001 g and transfer this test portion to a 500 ml conical flask (6.5). Add (250 f 1) ml of methanol to the flask and close the flask immediately, Shake on the mechanical shaker (6.2) for 30 rein, with a shaking frequency of155 rein-l, 9.2.2 If a sufficiently sized sample is not available, the determination may also be carried out with a reduced test porticm. The minimum test portion is 0,5 g. In this case use a 250 ml conical flask and add at least 50 ml of methanol. 9.2.3 For the determination of the water content of tobacco stems and tobacco leaves, an extraction time of 30 min is not sufficient, In this case extract the sample in a 500 ml conical flask with 250 ml of methanol, shake for 30 min and let stand for at least 24 h, The test potions should be gently swirled or mixed mechanically prior to removal of the analysis aliquot. In special cases a longer extraction time may be necessary, In this case extract the sample until constant results are obtained, i.e. the difference between the two calculations at different times is equal to or less than 0,5 g per 100 g, 9.2.4 If the extract is not analysed on the same day, store in a refrigerator. After conditioning to room temperature, the extract should be analysed. 9.3 Preparation oftitration apparatus Prepare the titration apparatus in accordance with the instructions for use. Add sufficient methanol (5.2) to the titration vessel (6.1.4) so that the tips of the platinum double electrode are completely immersed during stirring. Titrate the contents of the titration vessel to the end-point by addition of Karl Fischer reagent. 9,4 Blank test Transfer (250 + 1) ml of the methanol (5.2) to a 500 ml conical flask (6.5), and take it through the same operations as the sample extractions (9.2). Take from the conical flask an aliquot portion of 20,0 ml of the methanol using a one-mark pipette (6.4) and transfer to the titration vessel (6.1.4). Titrate with Karl Fischer reagent and record the value. Repeat the blank test, If the difference between the values of two determinations is less than or equal to 0,05 ml, calculate the mean value. Otherwise repeat the whole determination, The blank value, l?,is given by the equation f+ (2) ‘m where Vb isthe mean volume, in millilitres, of the Karl Fischer reagent used for the blank test; I’m isthe volume of the aliquot portion of methanol, in millilitres. 4 IS 9379:2008 ISO 6488:2004 9.5 Determination Transfer 10ml of the methanolic sample extract into the titration vessel usinga one-mark pipette (6.4) and titrate. After completion of the titration, remove the titrated solution and rinse the titration vessel with methanol. Repeat the determination. Calculate the water content. If the difference between the two calculations is less than or equal to 0,5 g per 100 g, calculate the mean value. Otherwise repeat the whole determination. 10 Expression of results The water content of tobacco, WT,expressed as milligrams per gram, is given by the equation [v~-(B. va)]Ev —— (3) ‘T m.L’a where v~ isthevolume, inmillilitres, of Karl Fischer reagent used for the titration ofthe sample extracc B isthe blank value (9.4); [j isthe volume of the aliquot portion, in millilitres, of the sample extract titrated; E is the water equivalent of the Karl Fischer reagent, in milligrams of water per miliilitre of reagent (Clause 7); v isthe total volume, in millilitres, of the sample extract prepared; m isthe mass, in grams, of the test portion. Express the result to the nearest milligram per gram.