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 6092-2-6 (2004): Methods of Sampling and Test for Fertilizers, Part 2: Determination of Nitrogen, Section 6: Ammoniacal Nitrogen Content in the Presence of Other Osbstances which Release Ammonia When Treated with Sodium Hydroxide - Titrimetric Method [FAD 7: Soil Quality and Gertilizers] “!ा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 6092 (Part 2/See 6): 2004 ISO 7408:1983 Indian Standard METHODS OF SAMPLING AND TEST FOR FERTILIZERS PART 2 DETERMINATION OF NITROGEN Section 6 Ammoniacal Nitrogen Content in the Presence of Other Substances which Release Ammonia when Treated with Sodium Hydroxide — Titrimetric Method ICS 65.080 C)BIS 2004 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 February 2004 Price Group 3 Fertilizers Sectional Committee, PCD 20 NATIONAL FOREWORD This Indian Standard (Part 2/See 6)which isidentical with ISO 7408:1983 ‘Fertilizers — Determination of ammonical nitrogen content in the presence of other substances which release ammonia when treated with sodium hydroxide — Titrimetric method’ issued bythe International Organization for Standardization (ISO) was adopted bythe Bureau of Indian Standards, on the recommendations ofthe Fertilizers Sectional Committee and approval of the Petroleum, Coal and Related Products Division Council. The text of ISO Standard has been proposed to be 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 tothis 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. IS 6092 (Part 2/See 6) :2004 ISO 7408:1983 lndan Standard METHODS OF SAMPLING AND TEST FOR FERTILIZERS PART 2 DETERMINATION OF NITROGEN Section 6 Ammoniacal Nitrogen Content in the Presence of Other Substances which Release Ammonia when Treated with Sodium Hydroxide - Titrimetric Method 1 Scope and field of application 3.9 Mixed indicator solution: screened ethanolic mathyl red solution, This International Standard specifies a method for the deter- mination ofthe ammoniacal nitrogen content offertilizers con- Mix 50mlofa2g/1ethanolic methyl redsolutionwith 50 mlof taining other substances, such as urea or urea-aldehyde con- a 1g/l ethanolic methylene blue solution. densates, which release ammonia in the presence of sodium hydroxide. The colourof thisindicator changes from lilacinacidmedium, viagrey at pH 5,4, to green inalkaline medium. 2 Principle 3.1O Ammonium sulfate, dried to constant mass at Entrainment, by means of a strong current of air, of the am- Im “c. monia from a moderately alkaline test mixture at ambient temperature into standard volumetric sulfuric acid solution. 3.11 Urea. Back-titration of the excess sulfuric acid with standard volumetric sodium hydroxide solution. 4 Apparatus 3 Reagents Ordinary laboratory apparatus and During the analysis, useonly reagents of recognized analytical grade, and only distilled water orwater of equivalent purity. 4.1 Entrainment apparatus. 3.1 Nonyl alcohol (nonanol). The components oftheapparatus maybe connected bymeans ofrubber bungsandtubingorbytheuseofground glassjoints. 3.2 Potassium carbonate, saturated s olution at room temperature. Ground glassjoints should be heldbyspring clamps toensure that they are leak-tight. Rubber bungs and tubing should be replaced when they begin to perish or show signsof wear. 3.3 Sulfuric acid, approximately 590 g/1 solution. A suitable apparatus isillustrated infigures 1and 2 and com- 3.4 Sulfuric acid, standard volumetric solution, prisesthe following components: c(H$30.J = 0,25 mol/l.l J 4.1.1 Double-necked bottle, of capacity 350 to400 ml. 3.5 Sulfuric acid, standard volumetric solution, C(H2SOJ = 0,05 mol/1.2) 4.1.2 Inlet tube, fitted with a mushroom-ahaped air distributor. 3.6 Sodium hydroxide, approximately 120g/1 solution. This distributor hasanexternal diameter of20 mm and hassix 3.7 Sodium hydroxide, standard volumetric solution, openings inthe rim, each 1 * 0,2 mm indiameter. c(NaOH) = 0,5) mol/l.l J NOTE– Theshapeofthedistributorandthenumberofholesand 3.8 Sodium hydroxide, standard volumetric solution, theirdiametersareimportantinensuringadequatedistributionofair c(NaOH) = 0,10 mol/1.z} bubblesdespitethastrongflowofair. 1) Hithertoexpressedas“0,50Nstandardvolumetricsolution”. 2) Hithertoexpressadas“O,10Nstandardvolumetricsolution”, 1 IS 6092 (Part 2/See 6) :2004 ISO 7408:1983 4.1.3 Outlet tube, with asingle bulb splashhead. b) thaother bottfe(4.2.1)inwhich hasbeanplaced250ml of the sulfuric acidsolution (3.3); If ground glassjoints are used, the inlet tube (4.1.2) and the outlet tube with its splash head (4.1.3) form one rigid glass c) the empty bottle (4.2.2). assembly. If a rubber bung isused, the inlet and outlet tubas shallbeseparate andtheinlettubeshallbestraightandshallbe Connect the flowmeter (4.7) to the empty bottle (4.2.2). of uniform diameter at the top end. If compressed air isuaad, connect the compressed air source 4.1.4 Inlet tube, similarto that described in4.1.2. (4.5) totheflowmetar (4.7). Ifsuctionisused,connect thesuc- tiondevice (4.6), viatheflask(4.1.6)totheconicalflask(4.1.5), 4.1.5 Conical flask, of capacity 500 ml. aashown infigure 2. NOTE– Theflask(4.1.6)preventswaterenteringtheapparatusintha 4.1.6 Thraa-necked flask (or conical flask of capacity eventofpraeeureflactuations. MOml), fitted with aninlettube, anoutlattube andastopcock (onlyrequiredwhen suction isusedinsteadofcompressed air). Ensurethat allthe connections are airtight. 4.2 Washing bottles. 5.3 Determination 4.2,1 Two waahing bottles, of capacity 500 ml, with the 5.3.1 Fertilizers of known composition usual inlet and outlet tubas of diameter 6 mm without bulb sDlashhead. Depending on the expected ammoniacal nitrogen content of the sample, measure into the flask (4.1.5), by means of a 4.2.2 Washing bottle, similartothosedescribed in4.2.1, but pipette, the appropriate volume oftheappropriate sulfuricacid with a shorter inlettube. solution (3.4 or3.5) specified inthe table. Add water untilthe levelof the liquidisabout 50mm above the orifice of the inlet tuba (4.1.4) andthen add5dropaof the mixed indicator aoiu- 4.3 Four pipettes, of capacities 50 – 25 – 20 and 10ml. tion(3.9). 4.4 Three burattea, of capacities 50 – 25 and 10ml. Add, through the side-neck of the double-necked bottle (4.1.1), 50 ml ofwater, afew drops of the nonyl aicohol (3.11 4.5 Compressed air source, fitted with aregulator capable and render the soiution alkaline by adding 50 ml of the of controlling the airflow rate at about 3000 ml/min, or saturated potassium carbonate solution (3.2). NOTE– Thaadditionofnonylalcoholpreventsfoamingwhanthaair 4.6 Suction devica, for example awater jet pump, capable ispassed. of maintaining anairflow rate through the apparatus at about 3IXO ml/min. immadiateiy closethe side-neck of the bottle and, usingcom- pressionorsuctionasappropriate, starttheairflow. Adjust the 4.7 Flowmeter, to measure the flow o f air. airflow ratetoabout3000 ml/rhin andpassairthrough theap paratus for 2 h. 5 Procedure Lowartheconicalflasksothat ita~paupportatheendofthein- lettuba (4.1.4). Rinsethe outaide ofthe tube with water, col- 5.1 Test portion lecting the rinsingsinthe flaak, and stop the airflow. Weigh, to the nearest 0,001 g, approximately 1 g of the Titrate theresidualacidintheconicalflaskwith theappropriate laboratory sample.1) sodium hydroxide solution (seathe tabie) tothe neutral coiour (grey) of the mixed indicator solution (3.9). Transfer the test portion to the double-necked flask (4.1.1). Table – Reagetis ‘required for titration 5.2 Assembly of the apparatus Sodium Expected Sulfuric acidsolution hydroxide Assemble the entrainment apparatus (4.1). amnmitroongiaecnal addedtot(h4e.1c.5oinical flask fosroltuhteiotnftruastieodn content, Connect inserieswith the doubla-necked bottle (4.1.1), inthe % (m/m) Identity Volume, Identity ml (concantrationl following order {seefigure 1): > 3,5 3.4 40,0 3.7(0,5mol/1) > 1,0and< 3,5 3.5 40,0- 3.8(0,1mol/1) a) one of the bottles (4.2.1) in which has been placed < 1,0 3.5 10,0 3.8(0,1mol/1) 250 mlof the sodium hydroxide solution (3.6); 1) The preparation ofsamples offertilizera willform the subject ofafuture Intamational Standard. 2 IS 6092 (Part 2/See 6) :2004 ISO 7408:1983 5.3.2 Fertilizers of unknown composition Cz isthe concentration, in moles per Iitre, of the sodium hydroxide solution usad for the determination and for the Carry out the procedure specified in5.3.1 for samples having blank test; ammoniacal nitrogen contents greater than 3,5 % (m/m) and then continue asfollows. k’, isthe volume, inmillilitres, ofthe sulfuric acidsolution usadfor the determination and for the blank test: After removing the conical flask (4.1.5), substitute another similar flask containing 10,0 ml of the standard volumetric Vz is the volume, in millilitres, of the sodium hydroxide sulfuricacidsolution (3.4), 5dropsofthe mixed indicator solu- solution usedfor the determination; tion (3.9) and sufficient water for the level of liquid to be 50mm above the orifice of the inlettube. Restan the airflow, V3 is the volume, in millilitres, of the sodium hydroxide adjustitto about 3000 ml/min and passthe airfor 1h. Lower solution usadfor the blank test; theconicalflasksothat itslipsupportstheendoftheinlettube (4.1.4). Rinsethe outside ofthetube with water, collecting the m. isthe mass, ingrams, of the test portion (5.1). rinsingsinthe flask and stop the airflow. Titrate the residual acid in the conical flask with the sodium 7 Precision hydroxide solution (3.7) to the neutral colour (grey) of the mixed indicator solution (3.9). Combine the results of each determination. Precision data have bean analysed statistically from an inter- Iaboratory study in which 16 laboratories (6 countries) par- ticipated with 7 levels. No statistical relationship between 5.4 Blank test repeatability (r)orreproducibility (1?)andthemean valuaofthe .— At the same time asthe determination, carry out a blank test ammoniacal nitrogen content of the samples was found. usingthesamereagents butomitting thetestportionandusing the sulfuric acidsolution (3.5) and the sodium hydroxide solu- 7.1 Repeatability, r tion (3.8). The difference between two individual test results, obtained 5.5 Check test Simultaneously or in rapid succe=”on by the same analyst, usingthe same apparatus, onidentical test material, underthe Periodically, carry out acheck test onthe efficiency ofthe ap- same operating conditions, should not exceed 0,16 % (m/m), paratus and the accuracy of the test method, asfollows. expressedasnitrogen (N)content, ataconfidence levelof95%. Weigh 4,716 gofthe ammonium sulfate (3.10) and25gofthe urea(3.11)intoa250 mlone-mark volumetric flask. Dissolvein 7.2 Reproducibility, R 200 mlof water and dilute to the mark with water. The difference between two individual and independent test Use asthe test portion 25,0 ml of this solution, equivalent to results, obtainad bydifferent analysts indifferent laboratories, 1(KImg of ammoniacal nitrogen, and usethe same conditions onidenticalteatmaterial, shouldnotexceed 0,71 % (m/m), ex- asfor the determination andthe blank test and with the same pressedasnitrogen (N) content, ataconfidence levelof95 %. indicator. 8 Test report 6 Expression of results Theammoniacal nitrogencontent, expressedasnitrogen(N) as The teat report shall include the following information: apercentage by mass, isgiven bythe formula a) areference tothisInternational Standard, i.e. ISO7408; lm 1 [(2 V,c, - v~c~)– (2 V,c, - VSCJ x 14,006 x m. x 103 b) the resultsand the method of expression used; where c) details of any unusual features noted during the deter- mination; c1 isthe concentration, in moles per Iitre, of the sulfuric acid solution usedfor the determination and for the blank d) details of any operations not included in this interna- test; tional Standard, or regarded asoptional. 3 Outlet tube (4.1.3) —— A Inlet tube fu (4.1.2) o 0 7 * .— /’,———=— T ./ h Ground glass\ x“ joint, in accordance + Wasn,m..g.L.rmmu,-e1 with ISO 383 Flowmeter (4.2.1) (4.7) Washing bottles (4.2.2) L [\L ConicalflaskJ (4.1.5) Figure 1– Typicalapparatus for the determination of ammoniacal nitrogen content using compressed air —--~ Todouble-necked bottle (4.1.1) uction P Coniil Fksk(4.,1.6) (4.1.5) ) Figure2 – Typicalapparatua for the determination of ammoniacal nitrogen content using auction a