KENYA STANDARD       DKS 2470 :2013  
           
 
          
 
HEXANE  FOR INDUSTRIAL USE  - SPECIFICATION  
 
 
             
 
© KEBS 2012              
 
  
TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were represented on the Technical Committee:  
 
Unive rsity of Nairobi  
Agrochemical and Food Company  
Kenyatta University  
KIRDI  
Government Chemist  
MOR  – Materials Dept.  
Consumer Information Network   
Spectre International  
Marshal l Fowler  
Kel Chemicals  
Associated Battery Manufacturers  
Unilever (K) Ltd  
Pan Afric an Chemicals  
Athi River Mining  
Ministry of Medical Services  
Galaxy Paints and Coatings  
Agricultural Association of Kenya  
Betachem Chemicals  
TATA Chemicals Magadi  
Kenya Bureau of Standards   Secretariat  
 
     
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
© Kenya Bureau of Standards , 2013 
 
 Copyright. Users are reminded that by virtue of section of the Copyright Act, Cap. 12 of 2001 of the Laws of Kenya, copyright subsists 
in all Kenya Standards and except as provided under section 26 of this Act, no Kenya Standard produced by Kenya Bureau of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing 
from the Managing Director.  
 
 
 
 
 
 
 
 
 
  
 KENYA STANDARD                  DKS 2470:  2013  
                  
 
           
HEXANE FOR INDUS TRIAL USE - 
SPECIFICATION 
 
 
                    
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region     Lake R egion          Rift Valley Region  
P.O. Box 99376, Mombasa- 80100   P.O. Box 2949, Kisumu- 40100        P.O. Box 2138, Nakuru-20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814  
  DKS 2470: 2013           ©KEBS  
 
 2  
Preface  
 
This Kenya Standard was prepared by the Technical Committee on Industrial solvents and chemicals under 
the authority of Kenya Bureau of Standards.  
 
Hexane is a hydrocarbon which is  a colourless liquid at room temperature.  
 
It is mainly used as a non- polar solvent. Other uses include preparation of adhesives, coatings, printing inks, 
as raw materials in chemical synthesis operations and as solvent in various kinds of extraction operations.  
 
This Kenya Standard addresses the requirements of industrial hexane, test methods and packaging and 
marking requirements  
 During the preparation of this standard, reference was made to the following publications and 
acknowledgement is made for its  assistance with thanks:  
 
• D 1836- 07: - Standard Specification for Commercial Hexanes  
• D611- 12:- Standard Test Methods for Aniline Point and Mixed Aniline Point of Petroleum 
Products and Hydrocarbon Solvents . 
• D2710- 09: Standard Test Method for Bromine Index of Petroleum Hydrocarbons by 
Electrometric  Titration . 
• D3120- 08: Standard Test Method for Trace Quantities of Sulfur in Light Liquid Petroleum  
 Hydrocarbons by Oxidative Microcoulometry . 
• D1133- 10: Standard Test Method for Kauri -Butanol Value of Hydrocarbon Solvents1  
• D4367- 02 Standard Test Method for  Benzene in Hydrocarbon Solvents by Gas  
Chromatography  
• IS 3470:2002 Hexane, Food Grade -  Specification  
 
 
 
 
 
  
 
 
 
 
 
 
 
 
  
 
 
 
 
 
 
  
 
 
 
  
 ©KEBS    DKS 2470:2013  
 
 3  
 
  
 
 
 
 
 
  
 
 
KENYA STANDARD  
 
HEXANE  FOR INDUSTRIAL USE  - SPECIFICATION  
 
 
 
1. SCOPE  
 
This Kenya Standard specifies requ irements and methods of test for hexane  for  industrial use.  
It has a chemical formula of C6H14. 
Nb This standard does not cover food grade hexane  
 
 2. REQUIREMENTS  
 
 Hexane shall satisfy the requirements specified in the Table below:  
   
  Table 1: Require ments for Hexane  
 
SL.NO  Characteristics  Requirements  Method of test  
1 Appearance  Clear and free 
from suspended 
matter  Visual  
2 Colour, Lovibond scale, Hazen Units  10 maximum   Annex A   
3 Specific Gravity, at 20oC 0.6594  KS 666  
4 Distillation range at 1013 mbar, ºC  
 
IBP 
D.P  
 
63 
71 KS 666  
5 Refractive Index  at 20oC 1.375 -1.384  KS 666  
6 Residue on evaporation ,mg/100ml,  1 max  KS 914  
7 Odor  Non-residual  KS 914  
8 Aniline point  570C min  Annex B  
 Benzene content, weight%,  0.1 Annex C  
 Bromine index,  100 max  Annex D  
9 Kauri -butanol value,  33 max  Annex E  
 Sulfur, ppm,  5 Annex F  
10 Reaction of non volatile residue 
(Neutrality test)  Neutral to methyl 
orange  Annex  G 
 
 
4. MARKING AND PACKING  
 
Hexane  shall be packaged in suitable and serviceable container s and marked indelibly with the 
following information:  
 DKS 2470: 2013           ©KEBS  
 
 4 (a) Name of the product  
(b) Manufacturer’s name and/or registered trade mark;  and address  
(c) Country of origin  
(d) Net weight;  
(e) Batch Number  
(f) The words ‘inflammable’ and its Standard S ymbol;  
(g) Precautionary measures i.e . may cause irritation to the eyes, respiratory system  and skin.  
 
 
  
  
 
ANNEX   A 
 
DETERMINATION OF COLOUR IN HAZEN UNITS  
(LOVIBOND SCALE)  
 
A.1 PRINCIPLE  
 
Visual comparison of the colour of a sample with that colour of standards, and expression of  the 
result in term s of hazen  
 
Note: For routine control purposes an instrument such as a comparator, colorimeter or 
spectrophotometer may be used, provided that it has first been established that the results so 
obtained are identical with those obtained by visual comparison.  
 
A.2 REAGENTS   
 
Distilled water, or water of equivalent purity, shall be used in the test.  
 
A.3 APPARATUS   
 
Ordinary laboratory apparatus and the Lovibond comparator  
 A.3.1 Two colorimetric tubes, flat based if possible, with a graduation mark at least 100 mm above the 
base and matched especially with respect to colour of glass and height of graduation mark above the 
base.   Suitable tubes are available commercially as 50 mL or 100 mL Nessler Cylinders.  
 
For the measurement of low colorations (l ess than 50 Hazen Units), the height of the graduation 
mark above the base must be greater than for the measurement of deeper colours and must be 
sufficient that, on looking through this greater depth of liquid, clear distinction between the standard 
Hazen  matching solutions can be observed.  
 
 
 
NOTE: 1. For routine control purposes, a colorimetric or spectrophotometer may be used, the 
instrument being standardized by means of the standard colorimetric solutions 
provided that it has been confirmed that the use of that instrument gives the same 
results as does visual comparison.  
 
A.4 Expression of Results  
 
Express the colour of the sample as the number of Hazen colour units  
 A.5 TEST REPORT  
 
The test report shall include the following particulars:  ©KEBS    DKS 2470:2013  
 
 5  
(a) the refer ence of the method used  
 
(b) the result, expressed in Hazen colour units  
 
(c) any unusual features noted during the determination  
 
(d) any operation not included in this standard or regarded as optional.  
 
  
Annex B  
Determination of Aniline  Point  
 
B.1 The test method covers the determination of  aniline point.  Aniline point is  the minimum equilibrium 
solution temperature for equal volumes of aniline and sample.  
The aniline point is useful as an aid in the characterization of pure hydrocarbons and in the analysis of 
hydrocarbon mixtures.  In homologous series the aniline points increase with increasing molecular weight.  
 
B.2 Apparatus  
 
B.2.1   Heating and Cooling Bath —A suitable air bath, a nonvolatile, transparent liquid bath, or an infrared 
lamp (250 to 375 W), provided with means for controlling the rate of  heating.  
Water should not be used as either a heating or cooling medium since aniline is hygroscopic and moist 
aniline will give erroneous  test results.  
 
B.2.2  Thermometers,  or other temperature sensing devices,  such as thermocouples or platinum resistance 
thermometers  that cover the temperamental range of interest and can provide equivalent or better accuracy 
and precision.  
B.2.3  Pipette , or equivalent volume dispensing devices, capable of delivering volumes with c apacities of 
10 ± 0.04 mL and 5 ± 0.02 mL, for use in the test.  
 
B.2.4   Balance —A laboratory balance sensitive to 0.01 g,  suitable for weighing the tube and sample when 
the sample cannot be pipetted conveniently.  
 
B.2.5   Safety Goggles.  
 
B.2.6   Plastic Glo ves, impervious to aniline.  
 B.3 Reagents  
B.3.1   Aniline  (Warning —Aniline should not be pipetted directly  by mouth because of its extreme toxicity. 
Aniline is also  toxic by absorption through the skin even in very small  quantities , and should be handled wi th 
great caution.) The aniline shall be sufficiently pure . 
 
B.3.2  Calcium Sulfate, anhydrous.  
 B.3.3  The apparatus shown in Fig. B -1 shall consist of the following  
B.3.3.1 Test Tube, approximately 25 mm in diameter and 150 mm in length, made of heat -resist ant glass.  
B.3.3.2  Jacket, approximately 37 to 42 mm in diameter  and 175 mm in length, made of heat -resistant glass.  
B.3.3.3 Stirrer, manually operated, metal, approximately 2 mm in diameter metal wire as shown in Fig. B-1 
B.3.3.4 A concentric ring shall be at the bottom, having a diameter of approximately 19 mm. The length of 
the stirrer to a right -angle bend shall be approximately 200 mm. The right-angle bend shall be approximately 
55 mm long. A glass  sleeve approximately 65 mm in length of 3- mm inside di ameter  shall be used as a 
guide for the stirrer or a ny suitable mechanical  device for operating the stirrer  
 B.4  Procedure  
 
B.4.1  Specified volumes of aniline and sample, are placed in a tube and mixed 
mechanically. The mixture is heated at a controlled r ate until  DKS 2470: 2013           ©KEBS  
 
 6 the two phases become miscible. The mixture is then cooled at  
a controlled rate and the temperature at which two phases  
separate is recorded as the aniline point or mixed aniline point.  
 
B.4.2  Dry the sample by shaking vigorously for 3 to 5 min with about 10 volume % of a suitable drying 
agent such as  anhydrous calcium sulfate ( or anhydrous sodium sulfate) . 
Remove any  suspended drying agent by use of a centrifuge or by filtration.  
Clean and dry the apparatus. Deliver 10 mL of  aniline and 10 mL of the dried sample into the test tube fitted 
with stirrer and thermometer. If the material is too viscous for volumetric transfer, weigh to the  
 
 
 
 
Fig. B -1 Aniline Point Apparatus  
   
 
 
 
 
 
 
 
 
 
nearest 0.01 g a quantity of the sample corresponding to 10 mL at room temperature. Center the 
thermometer in the test tube so that the immersion mark is at the liquid level, making sure that  the 
thermometer bulb does not touch the side of the tube.  Center the test tube in the jacket tube. Stir the mixture 
rapidly  using a 50- mm stroke, avoiding the introduction of air  
bubbles.  
 
B.4.3  If the aniline- sample mixture is not miscible at room  temperature, apply heat directly to the jacket 
tube so that the temperature rises at a rate of 1 to 3°C min by  removing or reducing the  heat source until 
complete miscibility  is obtained. Continue stirring and allow the mixture to cool at  a rate of 0.5 to 1.0°C min. 
Continue cooling to a temperature of 1 to 2°C below the first  appearance of turbidity, and record as the 
aniline point the temperature at which the mixture suddenly becomes cloudy  throughout. This temperature, ©KEBS    DKS 2470:2013  
 
 7 and not the temperature of separation of small amounts of material, is the  minimum equilibrium solution 
temperature.  
 
The true aniline point is characterized by a turbidi ty that  is so cloudy as to obscure the thermometer bulb in 
reflected light.  
 B.4.4  If the aniline- sample mixture is completely miscible  at room temperature, substitute a non- aqueous 
cooling bath for  the heating source, allow to cool at the rate specified i n B.4.3  
and determine the aniline point as described.  
B.4.5   Repeat the observation of aniline point temperature by heating and cooling repeatedly until a report 
as directed in Section B.5 can be made.  
 
B.5 Report  
If the range of three successive observati ons of the aniline point temperature is not greater than 0.1°C  
report the average temperature of these observations, corrected for  thermometer calibration errors, to the 
nearest 0.05°C as  the aniline point.  
 
Annex C  
Determination of Benzene  
 
C.1  Summary  
This method is for determination by gas  chromatography of benzene at levels from 0.01 to 1 volume %  in hydrocarbon 
solvents.  
An internal standard, methyl ethyl ketone (MEK), is  added to the material and then introduced into a gas chromatograph  
equipped wit h two columns connected in series. The specimen passes first through a column packed with the nonpolar 
phase, methyl silicone, which separates the components  by boiling point. After octane has eluted, the flow  through the 
nonpolar column is reversed, flush ing out the  components heavier than octane. The octane and lighter  components then 
pass through a column with the highly polar  phase, 1,2,3 -tris(2 -cyanoethoxy)propane, that separates the aromatic and 
nonaromatic compounds. The eluted components  are detecte d by a conventional detector and recorded on a strip  chart. 
The peak areas are measured and the concentration of  each component is calculated by reference to the internal  
standard.  
C.2  Significance and Use  
C.2.1  Benzene is classed as a toxic and carcinoge nic material.  A knowledge of the concentration of this compound may 
be an  aid in evaluating the possible health hazards to persons  handling and using hydrocarbon solvents, but this test 
method  is not intended to evaluate such hazards.  
C.3  Apparatus  
C.3.1  Chromatograph— Any gas chromatographic instrument  that has a backflush system and flame ionization 
detector and  that can be operated at the conditions given in Table 2. The  detector -recorder combination must produce a 
4-mm deflection  for a 1 -μL specimen con taining 0.05 volume % MEK when operated at maximum sensitivity.  
 
C.3.2   Columns , one 0.8- m (2.5 -ft) length of 3.2 -mm ( 1⁄8-in.) outside diameter stainless steel tubing and one 4.6 -m 
(15-ft) length of 3.2- mm ( 1⁄8-in.) outsider diameter stainless steel tubing . 
 C.3.2  Recorder, Strip Chart —Potentiometer with  with a full -scale deflection of 1 mV, a full- scale response time of 2 s 
or less, and  a maximum noise level of 6 0.3 % of full scale.  
 
C.3.3   Microsyringe,  5-μL capacity.  
 C.3.4 Pipets, measuring 1 and 2 mL, graduated in 0.01 mL; 5,  10, and 20- mL capacity.  
C.3.5  Flasks, volumetric, 25 and 100- mL capacity.  
C.3.6  Vibrator, electric.  
C.3.7 Vacuum Source.  
C.3.8 Evaporator, vacuum, rotary.  
C.3.9 Flask, boiling, round -bottom, short -neck, joint, 500 -mL capacity. Su itable for use with the evaporator  
C.3.10 Lamp, infrared.  
C.3.11 Burets, automatic, with integral reservoir, 25 -mL capacity.  
 
 
 
 DKS 2470: 2013           ©KEBS  
 
 8  
 
 
 
 
 
TABLE 2 Instrument Conditions Found Satisfactory for  
Measuring Low Concentrations of Benzene in  
Hydrocarbon Solvents  
 
 
 
 
 C.4 . Reagents and Materials  
 
C.4.1   Purity of Reagents —Reagent grade chemicals shall be  used in all tests. Other grades may be used, 
provided it is first ascertained that the reagent is of  sufficiently high purity to permit its use without lessening 
the accuracy of the determination.  
C.4.2   Acetone.  
C.4.3   Chloroform.  
C.4.4   Diatomaceous Earth4 —Acid -washed, 60 to 80 mesh and 80 to 100 mesh.  
C.4.5   Helium, 99.99 % pure.  
C.4.6   Methanol.  
C.4.7   Methylene Chloride.  
C.4.8   Methyl Ethyl Ketone (MEK), 99.9 mol  %. 
C.4.9   Methyl Silicone. 4 
C.4.10 , 1,2,3-Tris(2 -Cyanoethoxy) Propane (TCEP). 4 
C.4.11  Calibration Standards.  
C.4.11.1 Benzene, 99
+ mol %.  
C.4.11.2. Isooctane, 99+ mol %.  
C.4.11.3. n-Nonane, 99+ mol %.  
 
C.5  Preparation of Columns  
 
C.5.1  Column Packing Preparation —Prepare the two packing materials, one containing 10 % methyl 
silicone and the other  25 % TCEP, as follows:  
Weigh 45 g of the acid- washed calcined diatomite support 60 to 80 mesh, into a 500- mL flask . Dissolve  5 g 
of the methyl silicone in approxi mately 50 mL of  chloroform. ( Warning —Chloroform is a toxic material and  ©KEBS    DKS 2470:2013  
 
 9 inhalation must be avoided.) Pour the methyl silicone– chloroform  solution into the flask containing the 
support. Attach the flask to the evaporator connect the vacuum, and start  the motor. Turn on the infrared 
lamp and allow the packing to  
mix thoroughly until dry.  
Weigh 75 g of acid- washed pink diatomaceous earth,  80 to 100 mesh, into a 500- mL flask . Dissolve 25 g of 
TCEP in 200 mL of methanol and pour into the flask  containing the sup port. Attach the flask to the 
evaporator , connect the vacuum, and start the motor. Turn on the infrared lamp and allow the packing to mix 
thoroughly until  dry, but do not heat the packing above 180°C.  
 
C.5.2   Column Preparation  
Clean the stainless steel tu bing as follows: Attach a metal funnel to one end of the steel tubing. Hold or 
mount the stainless steel tubing in an upright position and place a beaker  under the outlet end of the tubing. 
Pour about 50 mL of  methylene chloride into the funnel and allow i t to drain through the steel tubing into the 
beaker. Repeat the washing with 50 mL of acetone. Remove the funnel and connect the steel tubing to an air 
line, by means of vinyl tubing. Remove all solvent from  the steel tubing by blowing filtered, oil -free air through 
or applying a vacuum.  
 
 Pack the 0.8- m (2.5- ft) tubing (Column A) with the methyl silicone packing and the 4.6- m (15- ft) tubing  
(Column B) with the TCEP packing as follows:  
Preform Columns A and B separately to fit the chromatographic  instrument . Close one end of each tubing 
with a small,  glass wool plug and connect this end to a vacuum source by  means of a glass -wool packed 
tube. To the other end connect a small polyethylene funnel by means of a short length of vinyl  tubing. Start 
the vacuum and pour the appropriate packing into the funnel until the column is full. While filling each 
column,  vibrate the column with the electric vibrator to settle the packing. Remove the funnel and shut off the 
vacuum source.  Remove the top 6 mm (1⁄4 in.) of packing and insert a glass  wool plug in this end of the 
column.  
 
C.6 . Preparation of Chromatographic Apparatus and  
Establishment of Conditions  
 C.6.1   Column Conditioning—Join Columns A and B as  shown in Fig. C-1. Connect the inlet of Column A t o 
the injection port of the chromatograph. Pass helium gas through the column at approximately 40 mL/min. 
Condition the columns in accordance with the following time- temperature schedule.  
 
 
Connect the outlet of Column B to the detector port.  Adjust the operating conditions to those listed in Table 
2, but do not turn on the detector circuits. Check the system for leaks.   Adjust the flow rate as follows:  
Set the value in the forward flow mode ( Fig. C-2(a)) and adjust Flow Controller A to give the required f low 
rate (Table 2). Measure the flow rate at the detector vent, specimen side.  Set the valve in the backflush 
position (Fig. C-2(b)) and measure the flow rate at the detector vent, specimen side. If the rate has changed, 
adjust Flow Controller B to obtain the required flow rate to within ± 1 mL/min.  
 
Turn on the detector circuit. Change the valve from  forward flow to the backflush position several times and 
observe the baseline. There should be no baseline shift or drift  after the initial peak resulting from  the 
pressure surge with the valve change. If there is a baseline shift, slightly increase or  decrease flow with 
Controller B to balance the baseline. (A  persistent drift indicates leaks somewhere in the system.)  
Determine time before backflushing, which v aries for  each column system and must be determined 
experimentally as  follows:  
Prepare a mixture of 5 volume % iso octane in n-nonane. Using the injection technique described in 11.3 and 
with the system in the forward flow mode, inject 1 μL of the isooctane– n-nonane mixture. Allow the 
chromatogram to run until the n -nonane has eluted and the recorder pen has returned to baseline. Measure 
the time in seconds from the injection until the recorder pen returns to baseline between the iso octane and n-
nonane peaks. At this point all of the isooctane but  essentially none of the n -nonane should have eluted. 
One half  of the measured time approximates the time to backflush and should be from 30 to 120 s.  DKS 2470: 2013           ©KEBS  
 
 10  
Repeat the run, including the injection, but switching  the system to the backflush mode at the determined 
backflush time. This should result in a chromatogram of iso octane with  little or no n-nonane evident.   If 
necessary, make additional runs, adjusting the time to backflush until a c hromatogram of all the iso octane 
and little  or none of the n -nonane is obtained. This established backflush time, including the actual valve 
operations, must be used in all  subsequent calibrations and analyses.  
 
 
 
 
FIG. C -1 Tubing Assembly and Instrumenta tion    FIG. C -2 Flow Switching System  
 
C.7  Calibration and Standardization  
 C.7.1   Standard Solutions —Prepare seven standard solutions  covering the range of 0 to 1 volume % 
benzene as follows: For  each standard, measure the volume of benzene listed below  into a 100- mL 
volumetric flask. Dilute to volume with  isooctane, with all components and glassware at normal room  
temperature, and mix thoroughly.  
 
 
 
C.7.2   Calibration Solutions —Accurately measure 0.5 mL of  MEK into a 100- mL volumetric flask, fill to th e 
mark with the first standard solution and mix thoroughly. Repeat  with each of the other standard solutions.  
 
C.7.3   Chromatographic Analysis —Using the conditions established  
in C.6.1 chromatograph each of the calibration solutions after injecting them as  follows: Flush the 5- μL 
microsyringe at least three times with the calibration solution and then fill with about 3 μL, avoiding inclusion 
of air bubbles  in the syringe. Slowly eject the material until 1.0 μL remains in the syringe. Wipe the needle 
with a tissue and draw back the plunger to admit 1 μL of air into the syringe. Insert the needle of the syringe 
into the septum cap of the chromatograph and push through the septum until the barrel of the syringe is  
resting against the septum cap; then rapidly push the plunger to the hilt and immediately withdraw the needle 
from the injection port. This injection technique is necessary to obtain sharp symmetrical  peaks.  
 ©KEBS    DKS 2470:2013  
 
 11 C.7.4  Calibration —Measure the areas of the benzene and of  MEK peaks by conventional means . Calculate 
the ratio of the benzene peak area to the MEK peak area. Plot the concentration of benzene versus the ratio 
as in Fig. C-3. The calibration must be done to ensure that the entire chromatographic  system is operating 
properly and that the concentrati on of any one component has not exceeded the linear response range of 
any part of the system —column, detector, integrator,  and other components. The calibration plot should be 
linear  . Determine the retention times for each component for  future identificat ion. 
 
 
 
 
NOTE —Determine for each analytical system.  
FIG. C-3 Typical Calibration Curve for Benzene  
 
C.8 Procedure  
C.8.1  Test Solution —Accurately measure 0.5 mL of MEK  into a 100- mL volumetric flask. Fill to the mark with 
the material under test and mix well.  Chromatograph a specimen from the test solution using the conditions 
established in C.6.1  and the injection technique.  
Note that t he valves must be turned to the backflush mode at the established backflush time so that 
undesirable components do not ent er Column B.  Identify on the chromatogram the benzene and the  internal 
standard MEK peaks from the retention times of the standards.The order of elution is nonaromatic 
hydrocarbons, benzene,  MEK, and toluene when using the specified columns, as shown in Fi g. C-4.  
Measure the areas under the benzene peak and under  
the MEK peak by conventional methods.  
 DKS 2470: 2013           ©KEBS  
 
 12 C.9 Calculation  
 
Calculate the ratio of peak area of benzene to the peak  area of MEK. Read from the calibration curve the 
volume % of  benzene corresponding t o the calculated peak ratio.  If the results are desired on a weight basis, 
convert to weight % as follows:  
 
Benzene, weight% (V/D) 0.8844  
 
where:  
V = benzene, volume %, and 
D = relative density of sample at 15.6/15.6°C (60/60°F).  
 
 Report the following information: benzene content in  volume or weight % to the nearest 0.005 %.  
Two results, each the mean of  duplicates, obtained by the same operator on different days  should be 
considered suspect if they differ by more than 0.027 % absolute.  
 
FIG. C -4 Typical  Chromatogram  
 
Annex D  
Test Method for Bromine Index  
 
D.1 Summary and Application 
 
This test method covers the determination of the amount of bromine- reactive material in petroleum 
hydrocarbons and is  
thus a measure of trace amounts of unsaturates in these materials. bromine index is the number of 
milligrams of bromine that will react with 100 g of sample under the conditions of the test.  
 
A known mass of the sample dissolved in a specified solvent is titrated with standard bromide- bromate 
solution. The end point is indicated by a dead stop electrometric titration apparatus when the presence of 
free bromine causes a sudden change in the electrical conductivity of the system.  
D.2 Apparatus  
D.2.1  Electrometric End Point Titration Apparatus —Any apparatus  designed to perform titrations to pre- set 
end points  may be used in conjunction with a high- resistance polarizing current supply capable of ©KEBS    DKS 2470:2013  
 
 13 maintaining approximately  0.8 V across two platinum electrodes and with a sensitivity such that a voltage 
change of appr oximately 50 mV  at these electrodes is sufficient to indicate the end point. Other  types of 
commercially available electric titrimeters, including certain pH meters, have also been found to be suitable.   
D.2.2  Titration Vessel —A jacketed glass vessel of approximately150- mL capacity of such a form that can 
be conveniently  maintained at 0 to 5°C (32 to 41°F). A pair of platinum  electrodes spaced not more than 5 
mm apart shall be mounted  to extend well below the liquid level. Stirring shall be by a mechanical or 
electromagnetic stirrer and shall be rapid, but  not so vigorous as to draw air bubbles down to the electrodes.  
 
D.2.3   Burets, 10 and 50- mL capacity.  
 D.2.4   Iodine Number Flasks, glass -stoppered, 500- mL capacity.  
 D.3 Reagents  
 
Only analytical grade reagents and distilled water  shall be used  
D.3.1  Preparation and Standardization :  
D.3.2  Bromide -Bromate Standard Solution ( 0.05 N )—Dissolve 5.1 g of potassium bromide (KBr) and 1.4 g 
potassium  bromate (KBrO3) in water and dilute to 1 L. Standardize to four  significant figures as follows: 
Place 50 mL of glacial  acetic acid ( Warning —Poison. Combustible. May be fatal if  swallowed. Causes 
severe burns. Harmful if inhaled) and 1 mL of concentrated hydrochloric acid (HCl, sp gr 1.19)  (Warning —
Poison. Corrosive. May be fatal if swallowed.  Liquid and vapor cause severe burns. Harmful if inhaled.) in a 
500-mL iodine number flask. Chill the solution in an ice bath for approximately 10 min, and with constant 
swirling of the flask, add from a 50- mL buret 40 to 45 mL of  bromide- bromate solution, estimated to the 
nearest 0.01 mL, at a rate such that  the addition takes between 90 and 120 s. Stopper the flask  immediately, 
shake the contents, place it again in the ice bath,  and add 5 mL of potassium iodide (KI) solution in t he lip of 
the flask. After 5 min, remove the flask from the ice bath and allow  the KI solution to flow into the flask by 
slowly removing the stopper. Shake vigorously, add 100 mL of water in such a manner as to rinse the 
stopper, lip, and walls of the flas k, and titrate promptly with the standard sodium thiosulfate (Na2S2O3) 
solution. Near the end of the titration, add 1 mL of  starch indicator solution and titrate slowly to the 
disappearance of the blue color. Calculate the normality of the bromidebromate solution as follows:  
 
N1 = A2N2/A1  
where:  
N1 = normality of the bromide- bromate solution,  
A1 = millilitres of the bromide- bromate solution,  
N2 = normality of the Na2S2O3 solution, and  
A2 = millilitres of the Na2S2O3 solution required for titration  of the bromide- bromate solution.  
 
D.3.3  Potassium Iodide Solution (150 g/L) —Dissolve 150 g of KI in water and dilute to 1 L.  
D.3.4  Sodium Thiosulfate, Standard Solution (0.05N) — Dissolve 12.5 g of sodium thiosulfate pentahydrate 
(Na2S2O3·5H2O) in water and add 0.0 1 g of sodium carbonate (Na2CO3)  to stabilize the solution. Dilute to 
1 L and mix thoroughly by  shaking. Standardize by any accepted procedure that determines  the normality 
with an error not greater than ±0.0002.  Restandardize at intervals frequent enough to detect changes of  
0.0005 in normality.  
 
D.3.5  Starch Indicator Solution —Mix 5 g of soluble starch with approximately 3 to 5 mL of water. If desired, 
add about  0.65 g salicylic acid as preservative. Add the slurry to 500 mL of boiling water and continue boiling 
for 5 to 10 min. Allow to cool and decant the supernatant liquid into glass bottles and seal well. Starch 
solutions (some preserved with salicylic acid)  are also commercially available and may be substituted.  
 
D.3.6  Sulfuric Acid ( 1+5)—Carefully add 1 volume of  concentrated sulfuric acid (H2SO4, sp gr 1.84) to 5 
volumes of  water and thoroughly mix. ( Warning —Poison. Corrosive.  Strong oxidizer. Contact with organic 
material may cause fire.  May be fatal if swallowed.)  
 
D.3.7  Titration Solvent —Prepare 1 L of titration solvent by  mixing the following volumes of materials: 714 mL 
of glacial  acetic acid, 134 mL of 1,1,1- trichloroethane or dichloromethane,  134 mL of methanol, and 18 mL of 
H2SO4 (1+5)  
D.3.8  Solvents:  DKS 2470: 2013           ©KEBS  
 
 14 - Acetic Acid, glacial. ( Warning —Poiso n. Combustible.  May be fatal if swallowed. Causes severe burns. 
Harmful  if inhaled.)  
- Methanol (Warning —Flammable. Vapor harmful.  May be fatal if swallowed. Causes severe burns. Harmful 
if inhaled.)  
- 1,1,1- Trichloroethane (Warning —Harmful if inhaled.  High concentrations may cause unconsciousness or 
death.  Contact may cause skin irritation and dermatitis.)  
- Dichloromethane (Warning —Harmful if inhaled.  High concentrations may cause unconsciousness or 
death.  Contact may cause skin irritation and dermatitis. ) 
D.4 Procedure  
D.4.1  Switch on the titrimeter and allow the electrical circuits  to stabilize in accordance with the 
manufacturer’s instructions.  Cool the titration vessel to 0 to 5°C by  circulating a suitable coolant through the 
jacketed titration vessel.  Introduce 110 mL of titration solvent into the titration  vessel and pipet in a quantity 
of sample as indicated in Table D-1. Switch on the stirrer and adjust to a rapid stirring rate, but  avoid any 
tendency for air bubbles to be drawn down into the soluti on. Allow the contents to cool to 0 to 5°C and 
maintain at this temperature throughout the titration.  
(Warning —Hydrocarbon samples, particularly those boiling below 205°C are flammable.)  
 
 Frequently the order of magnitude of the bromine index of a sample is unknown. In this case, a trial test is  
recommended using an 8 to 10- g sample in order to obtain the approximate magnitude of the bromine index. 
This exploratory  test should be followed with another determination using the appropriate sample size as 
indicated in Table D-1. The sample mass can be determined by obtaining the density of the sample and 
calculating the mass of a measured volume.   Set the end point potential. With each instrument, the 
manufacturer’s instructions should be followed for end point  setting and to achieve the sensitivity in the 
platinum electrode circuit . Depending on the titrator apparatus, add the bromidebromate solution manually or 
by microprocessor control in small increments from the buret. The end point of the titration is achi eved when 
the potential reaches the pre- set value and persists for more than 30 s.  
 
D.4.2    Blanks —Make duplicate blank titrations on each batch  of titration solvent and reagents. Less than 1.0 
mL of bromidebromate solution should be required.  
 
D.5 . Calcu lation  
Calculate the bromine index as follows:  
 
 
where:  
A = millilitres of bromide -bromate solution required for  titration of the sample,  
B = millilitres of bromide -bromate solution required for  titration of the blank,  
N = normality of bromide- bromate sol ution, and  
W = grams of sample.  
 
The difference between successive test results obtained by the same operator with the same apparatus 
under constant operating conditions on identical test  material would, in the long run, in the normal and 
correct  operation  of the test method, exceed 14 in only one case in twenty. 
 
 
 
Annex E  
Determination of Kauri -Butanol value  
 
E.1 Summary:   
kauri -butanol value, n— of a solvent , the volume in millilitres at 25°C of the solvent, corrected to a defined 
standard, required to pr oduce a defined degree of turbidity when added to 20 g of a standard solution of 
kauri resin innormal butyl alcohol.  
The kauri resin solution is standardized against toluene, which has an assigned value of 105, and a mixture 
of 75 % n -heptane and 25 % toluene on a volume basis, which has an assigned value of 40. The kauri -
butanol value is used as a measure of solvent power of hydrocarbon solvents. High kauri -butanol values 
indicate relatively strong solvency.  
 
 ©KEBS    DKS 2470:2013  
 
 15  
 
E.2 Apparatus  
E.2.1  Water Bath, capable of being maintained at 25 6 5°C. Alternatively, a temperature controlled 
environment maintained at 25 6 5°C may be used.  
 
E.2.2 Volumetric Flask, 200 -mL capacity.  
 
E.2.3 Erlenmeyer Flask, 250- mL capacity.  
 E.2.4 Sample Dispensing Device, Buret, of at least 50- mL capacity, or equivalent, that is capable of 
accurately determining the volume dispensed to the nearest 0.1 mL.  
 E.2.5 Print Specimen— A sheet of white paper having on it black 10 or 12 point print, No. 31 Bruce old style 
type.  
 
E.3  Reagents  
 
E.3.1 Kauri -Butanol Solution4 —Place in a 3- L flask 400 g of  clean, pale, bold kauri resin of Grade XXXX, 
XXX, or XX ground to pea- size or smaller. Add, while agitating vigorously,  2000 g of n -butyl alcohol,  Shake 
on a mechanical shaker until the resin goes into solut ion, warming to about 55°C, if necessary to aid 
solution. If a mechanical shaker is not available, fit the flask with a reflux  condenser and heat on a steam 
bath until all of the kauri resin is dissolved. Permit the solution to stand 48 h and then clarify  by filtering 
through a Büchner funnel with suction, using double filter paper and changing as frequently as necessary.  
 
E.3.2  Standard Toluene  
 
E.3.3  Heptane- Toluene Blend consisting of 25 ±  0.1 % toluene and 75 ±  0.1 % n -heptane on a volume 
basis, for use as a low-solvency standard. The heptane shall be spectroscopic,  HPLC, or knock test grade.  
 
E.4 Standardization  
 
E.4..1  Weigh out 20 ±  0.10 g of kauri -butanol solution in a 250-mL Erlenmeyer flask. Check that the 
temperature of the KB solution in the flask is 25 ±  5°C. If not, place the Erlenmeyer flask and its contents in a 
water bath or temperature controlled environment maintained at 25 ±  5°C and allow  to equilibrate for at least 
30 min. If the flask was placed in a water bath, remove the flask from the water bath. Titrate the  contents of 
the flask with the standard toluene. Swirl the contents of the flask during titration, periodically stopping to 
observe the clarity of the print beneath the flask. Gradually  reduce the successive amounts of toluene add ed 
as the end point is approached. The end point is reached when the sharp outlines of 10- point print placed 
directly beneath the Erlenmeyer  flask and observed through the liquid are first perceived to be obscured or 
blurred. The point where the print becomes  illegible is past the end point. Check the temperature in the flask 
immediately after the end point has been reached, and if  over 30°C or under 20°C, repeat the titration.  
 E.4..2 The volume of toluene used, in millilitres, represents the actual titer for the particular kauri -butanol 
solution at hand.  This value should lie reasonably close to 105 mL, but not over  110 nor under 100 mL. If 
these limits are exceeded,  adjust the  concentration of the kauri -butanol solution to bring the total  volume of 
tolue ne within them. Designate the final value using toluene as A. 
 
E.4.3 Weigh out 20 ±  0.10 g of the kauri -butanol solution  in a 250- mL Erlenmeyer flask  and place in the 
water bath. Titrate with the heptane- toluene  blend in the same manner . Designate the  volume, in millilitres, 
of the blend used in this titration as B. 
 
NB Freshly prepared kauri -butanol solution may change in  standardization from day to day. It is, therefore, 
desirable to permit the solution to age before initial standardization and, in any case, the standardization 
should be rechecked on successive days until the toluene  
factor and blend factor remain constant.  
 
 DKS 2470: 2013           ©KEBS  
 
 16  
E.5 Procedure  
 
E.5.1  Weigh 20 ± 0.10 g of the adjusted kauri -butanol  solution into a 250- mL Erlenmeyer flask. Check that 
the temperature of the KB solution in the flask is 25 ± 5°C. If not,  place the Erlenmeyer flask and its contents 
in a water bath or  temperature controlled environment maintained at 25 ±  5°C and allow to equilibrate for at 
least 30 min. If the flask was  placed in a water bath, remove the flask from the water bath.  
Fill the sample dispensing device with the solvent being tested.  Titrate the contents of the flask with the 
solvent. Swirl the contents of the flask during the titration, periodically stopping to observe the clarity of the 
print beneath the flask. Gradually  reduce the successive amounts of solvent added as the end point is 
approached. The end point is reached when the sharp outlines of 10- point print (see E.2.5 ) placed directly 
beneath the Erlenmeyer flask and observed through the liquid are first  perceived to be obscured or blurred. 
The point where the print  becomes illegible is past the end point. Check the temperature in the flask 
immediately after the end point has been reached and if over 30°C or under 2 0°C, repeat the titration. 
Designate the volume of solvent, in millilitres, to produce turbidity as C . 
 
E.6 . Calculation  
E.6..1 Calculate the kauri -butanol value, V, as follows:  
 
where:  
A = toluene required to titrate 20 g of kauri -butanol solution mL, 
 
B = heptane- toluene blend required to titrate 20 g of kauributanol  solution mL, and  
 C = solvent under test required to titrate 20 g of kauributanol  solution  mL. 
 
Report the calculated kauri -butanol value to the nearest  0.5 KB unit.  
 
 
Annex F  
Determinatio n of Sulphur  
 
F.1 Summary of Test Method 
F.1.1  A liquid sample is introduced into a pyrolysis tube  maintained at a temperature between 900-
1200°C, having a flowing stream of gas containing 50- 80% oxygen and 20- 50% inert gas (for example, 
argon, helium, et c.) Oxidative pyrolysis  converts the sulfur to sulfur dioxide, which then flows into a titration 
cell where it reacts with triiodide ion present in the electrolyte. The triiodide ion consumed is coulometrically  
replaced and the total current (I × t) requir ed to replace it is a measure of the sulfur present in the sample.  
The reaction occurring in the titration cell as sulfur  dioxide enters is:  
 
The triiodide ion consumed in the above reaction is generated coulometrically thus:  
 
These microequivalents of t riiodide ion (iodine) are equal to the number of microequivalents of titratable SO2 
ionentering the titration cell.  
 
F.2 Apparatus  
F.2.1 The configuration of the pyrolysis tube and furnace may  be constructed as is desirable as long as the 
operating paramet ers are met. Fig. F-1 is typical of apparatus currently in use.  
 
F.2.2 A typical assembly and oxidative gas flow through a coulometric apparatus for the determination of 
trace sulfur is  shown in Fig. F-2. 
 
F.2.3 Furnace— Maintained at a temperature sufficient to  completely pyrolyze the organic matrix, 900-
1200°C, and completely oxidize the organically bound sulfur to SO2.  Independently controlled inlet and outlet 
temperature zones are  optional. An electrical furnace has been found suitable to use.  ©KEBS    DKS 2470:2013  
 
 17  
F.2.4 Pyrolysis Tube — Fabricated from quartz and constructed so the sample is vaporized in a heated zone 
before the furnace and swept into the oxidation zone by an inert carrier  gas, where the vaporized sample 
mixes with oxygen and is  pyrolyzed. The inlet shall be constructed large enough to accommodate a sample 
boat completely into the oxidation zone of the pyrolysis tube or allow the direct injection of the sample into 
the heated zone before the furnace. The pyrolysis tube  shall have side arms for the introduction  of oxygen 
and inert  carrier gas.  
 
F.2.5 Titration Cell — Consisting of a sensor/reference pair of  electrodes to detect changes in triiodide ion 
concentration, a generator anode- cathode pair of electrodes to maintain a constant triiodide ion 
concentration, an inlet for gaseous  sample from the pyrolysis tube, and an outlet to vent the exit  gases from 
the titration cell. The reference electrode can be either an Ag/AgCl double junction reference electrode or a 
platinum wire in a saturated triiodide half -cell. T he sensor  electrode and both the anode and cathode 
electrodes of the generator are made of platinum. The titration cell shall require  mixing, which can be 
accomplished with a magnetic stir bar,  stream of gas, or other suitable means. Other sensor and reference 
electrodes may be used if they meet the performance criteria of this test method.  
 NOTE —Take care not to use excessive stirring and possibly damage the electrodes with the stir bar. The 
creation of a slight vortex is adequate.  
 F.2.6 Microcoulometer — The apparatus’ microcoulometer,  with variable attenuation and gain control, shall 
be capable ofmeasuring the potential of the sensing- reference electrode pair  and compare this potential to a 
bias potential. By amplifying this potential difference and appl ying the difference to a working- auxiliary pair of 
electrodes (the generator), a titrant is  generated. The microcoulometer integrates the amount of  current 
used, calculates the equivalent mass of sulfur titrated and calculates the concentration of sulfur i n the 
sample.  
 F.2.7 Strip Chart Recorder (Optional) —To monitor and plot  the mV potential of the titration cell during the 
analysis.  
F.2.8 Flow Control —The apparatus shall be equipped with  flow controllers capable of maintaining a constant 
supply of  
oxyge n and inert carrier gas.  
 F.2.9 Dryer Tube —The oxidation of samples produces water  vapor which, if allowed to condense between 
the exit of the  
pyrolysis tube and the titration cell, will absorb the SO2 formed and result in low recovery. Steps shall be 
taken to prevent such an occurrence. This is easily accomplished by placing a  phosphoric acid dehydration 
tube between the titration cell and exit of the pyrolysis tube. Other approaches, such as heating tape or 
permeation tubes, can be used if precision and accuracy  are not degraded.  
 F.2.10 Sampling Syringes —Microlitre syringes able to accurately  deliver 5 to 80 mL of sample are required. 
The volume  
injected should not exceed 80% of a syringe’s capacity.   
 
F.2.11 Sample Inlet System—Either type of sample inlet  system described can be used.  
 
F.2.11.1 Boat Inlet System —The inlet of the pyrolysis tube is  sealed to the boat inlet system. The system 
provides a cooled area before the furnace for the sample boat prior to quantitative introduction of sample into 
the b oat and is purged with the inert  carrier gas. The boat driving mechanism then fully inserts the boat into 
the oxidation zone of the furnace. The drive mechanism  shall advance and retract the sample boat into and 
out of  the oxidation zone of the furnace at a controlled and repeatable rate 
 
 DKS 2470: 2013           ©KEBS  
 
 18 
 
FIG. F -1 Typical Pyrolysis Tube  
 
 
 
FIG. F -2 Flow Diagram for Typical Coulometric Apparatus for Trace Sulfur Determination  
 
F.2.11.2 Boat Inlet Cooler (Optional) —Sample volatility  and injection volume may require an apparatus 
capable of  cooling the sample boat prior to sample introduction. Thermoelectric  coolers (peltier) or 
recirculating refrigerated liquid devices are strongly recommended. Switching sample boats  between each 
analysis may prove effective, provided sampl e size is not too large.  
 
F.2.11.3 Sample Boats —Quartz or other suitable material  which will not react with the sample or sulfur 
compounds  being analyzed and able to withstand the temperatures extremes  of the test method.  
 
F.2.11.4 Syringe Inlet System—The system shall deliver a quantitative amount of sample from a microlitre 
syringe into a heated area before the oxidation zone of the pyrolysis tube at  a controlled and repeatable rate. 
There the sample is volatilized  and the inert carrier gas stream purging the heated area transports the 
volatilized sample into the oxidation zone of the pyrolysis furnace. An adjustable drive mechanism capable of  
injecting the sample from a microlitre syringe at a constant rate between 0.5 to 1.0 mL/s is required  
 
NOTE: T ake care not to introduce the sample too fast into the oxidation zone of the furnace and overload the 
combustion capacity of the pyrolysis tube. Program the sample inlet system to deliver the sample at  a 
sufficiently controlled and repeatable rate to prevent any incomplete combustion by -products (coke or soot) 
from forming at the exit of the pyrolysis tube.  
 
F.2.12  Balance —With a weighing precision of 60.01 mg.  
 F.3  Reagents and Materials  
 
F.3.1 Quartz Wool —Grade fine.  
 
F.3.2  Acetic Acid (CH3COOH) —Glacial a cetic acid with  specific gravity = 1.05. ( Warning — Poison. 
Corrosive. Combustible.  May be fatal   if swallowed. Causes severe burns.  Harmful if inhaled.)  ©KEBS    DKS 2470:2013  
 
 19 F.3.3   Phosphoric Acid (85 % w/w) —Orthophosphoric acid  (H3PO4). ( Warning —Poison. Corrosive. May 
be fatal if swallowed.  Causes severe burns.)  
 
F.3.4   Inert Gas —Argon or helium, high purity grade (HP),5  used as carrier gas. ( Warning —Compressed 
gas under high  
pressure. Gas reduces oxygen available for breathing.)  
 F.3.5   Oxygen—High purity grade (HP),5 used as  the reactant  gas. ( Warning —Oxygen vigorously 
accelerates combustion.)  
 
F.3.6   Gas Regulators —Two -stage gas regulators shall be used for the oxygen and inert carrier gas.  
 
F.3.7   Cell Electrolyte Solution— Dissolve 0.5 g of potassium  iodide (KI) and 0.6 g of sodium azide (NaN3) 
in approximately  500 mL of high- purity water, add 6 mL of glacial acetic acid (CH3COOH), and dilute to 1000 
mL or follow the manufacturer’s  specifications.  
Take care to store bulk quantities of the electrolyte in a dark  place. It is r ecommended to prepare fresh 
electrolyte at least every three months.  
 F.3.8    Sodium Azide (NaN3), fine granular. ( Warning — Toxic. Causes eye and skin irritation. Explosive.)  
 
F.3.9   Potassium Iodide (KI), fine granular.   
 
F.3.10  Potassium Nitrate (KNO3) , fine granular. Used for the 1M Ag/AgCl double junction reference 
electrode.  
F.3.11   Iodine (I), 20 mesh or less, for saturated reference electrode.  
 
F.3.12  Toluene, Xylenes, Isooctane —Reagent grade. (Other  solvents similar to those occurring in the 
samp les being  analyzed are acceptable.)Asolvent blank correction is required  due to the inherent sulfur 
present in the solvents used for  standard preparation and sample dilution. ( Warning — Flammable solvents. 
Harmful if inhaled. Vapors may cause flash fire.)  
 F.3.13   Dibenzothiophene—FW 184.26, 17.399 % (mass/  mass) S  
 F.3.14    n-Butyl Sulfide —FW 146.29, 21.92 % (mass/mass) S   
 
F.3.15 Thionaphthene (Benzothiophene) —FW 134.20,  23.90% (mass/mass) S  
 F.3.16   Sulfur, Standard Solution (approximately 1000 mg- S/ mL)—Prepare a stock solution by accurately 
weighing approximately  0.5748 g of dibenzothiophene or 0.4652 g of n- butyl  sulfide or 0.4184 g of 
thionaphathene into a tared 100 mL, type A volumetric flask. Dilute to volume with a selected solvent.  This 
stock can  then be further diluted to prepare sulfur working and calibration standards as outlined in  
Tables F-1 to F -3  
 
F.3.17.  Potassium Chloride (KCl), fine granular. Used for the 1M Ag/AgCl double junction reference 
electrode.  
 
 
 
 
 
where:  
 
A = grams of standard.  
B = weight of fraction sulfur (S) in standard.  
C = weight of fraction standard purity.  
 DKS 2470: 2013           ©KEBS  
 
 20 F.3.18   Sulfur, Standard Working Solution —Prepare the working standards using standard type A 
volumetric pipet as  outlined in Table F-1. 
 
Working and calibration standards prepared on a regular basis  recommended, depending upon frequency of 
use and age. Stock solutions  typically have a useful life of about 3 months.Calibration standards can be 
prepared and diluted on a mass/mass basis, when calculation results are adjusted to accommodate them.  
Stock, working and calibration standards from commercial  sources can be used if checked for accuracy and 
can meet the performance criteria of this test method.  
 F.4 Hazards  
 
F.4.1  High temperature is employed in this test method. Extra care shall be exercised when using flammable 
materials near  the furnace.To preserve volatile components which are in some samples, do not uncover 
samples any longer than necessary. Samples should be analyzed as soon as possible after collection f rom 
bulk supplies to prevent loss of sulfur, or  contamination due to exposure or contact with sample container.  
 
F.5 Preparation of Apparatus  
F.5.1   Carefully insert the quartz pyrolysis tube into the furnace, and connect the oxygen and inert carrier 
gas l ines. Connect the boat drive system or syringe drive system  to the pyrolysis tube. Perform a leak check 
according to the manufacturer’s  instructions.   Assemble the titration cell, and add all required solutions,  
including cell electrolyte, according to the manufacturer’s  instructions.   Connect the titration cell to the 
apparatus according to the manufacturer’s instructions.   Adjust the flow of gases and set the furnace 
temperatures  and instrumental parameters according to the manufacturer’s  instructions.  
 
TABLE F-1 Recommended Preparation of Working Standards  
 
 
 
 
TABLE F-2 Recommended Calibration Standards versus Desired Calibration Range  
 
 
TABLE F-3 Recommended Preparation of Calibration Standards  
 
 
 
If using a boat inlet system, pre- bake the sample boat s used for the analysis per the manufacturer’s 
instructions.  
  ©KEBS    DKS 2470:2013  
 
 21 F.6.  Calibration and Standardization  
 
F.6.1  Following the manufacturer’s recommended procedures,  set the operational parameters of the 
apparatus for  internal calibration. If the apparatus is not so equipped, analyze the solvent blank and 
calibration standards, record their values  as μg or ng of sulfur, and manually generate a calibration curve.  
 
F.6.2  Calibration Standards —Select the desired calibration  range from Table F-2. Prepare the appropriate 
calibration standards  for the range selected as outlined in Table F-3. The calibrati on standards 
concentrations are calculated based on the formula below:  
 
 
 where:  
A = μg-S/mL of working or stock solution.  
B = mL of working or stock solution.  
 
NOTE —A calibration curve with three standards is recommended. It  is recommended to use standards 
covering the range of sulfur concentrations  expected in the samples being analyzed.  
 F.6.3   Select the appropriate syringe based on the recommended  sample size in Table F-4 for the 
concentration of  standards used to calibrate the apparatus.  
 
TABLE F-4 Recommended Sample Size for Expected Sample  
Concentrations  
 
 
 
F.6.4   Flush the microlitre syringe several times with the  sample prior to analysis. If bubbles are present in 
the liquid column, flush the syringe and withdraw a new sample.  11.5 The sample si ze can be determined 
volumetrically or  by mass with a syringe. The sample size should be 80% or less  of the syringe’s capacity.  
 
F.6.5   Volumetric Measurement —Obtain the volume of injected material by filling the syringe to the 
selected level,retracting th e plunger so the lower meniscus falls on the 10%  scale mark, and recording the 
volume of liquid in the syringe.  After the sample has been injected, retract the plunger again so the lower 
liquid meniscus falls on the 10% scale mark, and record the volume of  liquid in the syringe. The difference 
between the two readings is the volume of sample injected.  
 
F.6.6   Mass Measurement —The sample syringe may be weighed before and after the injection to 
determine the amount  of sample injected. This technique provides greater precision than the volume delivery 
method, provided a balance with a precision of 60.01 mg is used.   Once the appropriate sample size has 
been measured into the microlitre syringe, promptly and quantitatively deliver  the sample into the apparatus. 
Again, there are two alternative techniques available.  
 
F.6.7   Boat Inlet System —Add the sample by slowly discharging quantitatively the contents of the syringe 
into a  sample boat containing quartz wool, being careful to include the last drop from the tip of the syringe 
needle. Remove the syringe and immediately start the analysis. The apparatus’  baseline should remain 
stable until the boat approaches the furnace and volatilization of sample begins . The program of the inlet 
system should keep the boat compl etely in the oxidation zone of the furnace a time (residence time)  
sufficient to totally oxidize the sample before withdrawing the sample boat out of the furnace. Allow at least 2  
min for cooling before the next sample injection after the boat  has reached the fully retracted position. 
Reduce the boat drive introduction rate, sample size or both if coke or soot is observed on the exit end of the  DKS 2470: 2013           ©KEBS  
 
 22 pyrolysis tube. Increase the residence time for the boat in the oxidation zone of the furnace if coke or soot is 
observed on the boat after the analysis is finished.  
 
F.6.8   Syringe Inlet System —For direct injection, carefully  insert the syringe needle into the inlet of the 
combustion tube and attach the syringe to the driving mechanism. Allow time for the sample resi dues to be 
volatilized from the needle (needle blank). Once the baseline has been reestablished,  immediately start the 
analysis. Remove the syringe once the sample has been syringe once the sample has been completely  
injected and the analysis is finished.   Reduce the sample size, rate of injection, or both,  for the direct 
injection the test sample into the furnace if coke or soot is observed on the exit end of the pyrolysis tube.  
Calibrate the instrument using one of the following two techniques:  
 
F.6.9   Automatic Internal Calibration —Measure the calibration standards and solvent blank using one of 
the procedures  described in F.6.3 –F.6.8.  Analyze the solvent blank and each standard a minimum of three 
times. Calibrate the apparatus per  the manufacturer’s inst ructions. Use either a first or second order linear 
regression and use this calibration curve to  determine the amount of sulfur in the unknown sample. The 
system’s performance shall be checked each day of use.  
 
F.6.9   Manual Calibration Curve —Measure the solvent  blank and calibration standards using one of the 
procedures  described in F.6.3– F.6.8. Analyze the solvent blank and each calibration standard a minimum of 
three times and record their  absolute values in either μg or ng sulfur. Subtract the averaged blank value from 
each calibration standard and construct a  curve plotting the mass of sulfur measured for each 
calibrationstandard ( y-axis) verses the theoretical mass of sulfur injected.  Perfor m a first or second order 
linear regression and use the calibration curve to determine the amount of sulfur in the  unknown sample. 
The system’s performance shall be checked each day of use.  
If the fraction of sulfur converted to SO2 (recovery  factors) drops below 75% of the standard solutions, 
prepare fresh standards to check if the standards have been altered.  Procedural details should be reviewed 
if a low recovery factors  persist.  
 
F.6.10   Cleaning and Recalibration—Clean any coked or  sooted parts per the manufacturer’s instructions. 
Assemble and leak check the apparatus per the manufacturer’s instructions  after any cleaning or adjustment. 
Repeat instrument calibration prior to reanalysis of test samples.  
 
F.7  Procedure  
 
F.7.1   Obtain a test sample using  the procedure described in  Section 9. The sulfur concentration in the test 
sample shall be less than the concentration of the highest standard and greater  than the concentration of the 
lowest standard used in the  calibration. If required, a dilution shoul d be performed on either a weight or 
volume basis.  
 
F.7.2   Gravimetric Dilution, (mass/mass) —Record the mass of the test sample and the total mass of the 
sample and solvent.  
 
F.7.3   Volumetric Dilution, (mass/volume) —Record the  mass of the test sample and the total volume of the 
test sample and solvent.    Flush the sampling syringe several times with the unknown sample. Determine the 
sulfur concentration using one of the procedures described in F.6.3– F.6.8 .  Inspect the combustion tube and 
other flow path components to verify complete oxidation of the test sample.  
 ©KEBS    DKS 2470:2013  
 
 23 
 
 
FIG. F-3 Percent Recovery versus Temperature (°C)  
 F.7.4   Boat Inlet Systems —Reduce the boat drive introduction rate, sample size, or both, if coke or soot is 
observed on the exit end of the p yrolysis tube. Increase the residence time for  the boat in the oxidation zone 
of the furnace if coke or soot is  observed on the boat after the analysis is finished.   
 
F.7.5   Syringe Inlet Systems —Reduce the sample size, rate of injection, or both, for the direct injection the 
test sample into the furnace if coke or soot is observed on the exit end of the pyrolysis tube.  
 
F.7.6   Cleaning and Recalibration—Clean any coked or  sooted parts per the manufacturer’s instructions. 
Assemble andleak check the apparatus per the manufacturer’s instructions  after any cleaning or adjustment. 
Repeat instrument calibration prior to reanalysis of test samples.  DKS 2470: 2013           ©KEBS  
 
 24 F.7.8   To obtain one result measure each test sample solution three times and calculate the average 
value. If the sam ple size is determined by volume, density  values needed for calculations are to be 
measured at the temperature at which the sample was tested. If the sample size was determined by weight, 
density values are not required.  
 
F.8  Calculation  
 
F.8.1 Calculate the sulfur concentration in the test sample in mg/kg (ppm) as follows:  
 
 
where:  
 
C = sulfur found in test sample (either directly from the instrument or calculated manually from the calibration  
curve), μg.  
 
K = gravimetric dilution factor, mass of test sample/mass  of test sample and solvent, g/g.  
 
M = mass of test sample solution injected, either directly  measured or calculated from measured volume 
injected and density, V × D, mg.  
 
V = volume of test sample solution injected, either measured directly or calculated from measured mass  
injected and density, M/D, μL.  
 
D = density of sample, g/mL.  1000 = Factor to convert μg/mg to mg/kg (ppm).  
 
Annex G  
Neutrality Test  (Reaction of Non- Volatile Residue)  
 
G.1 Reagent  
Methyl orange shall be used as an indicator.  
 G.2 Procedure  
Dissolve 0.01g of methyl orange in 100ml of water.  
To a conical flask containing the non- volatile residue as in KS 914, add 100ml of distilled water and shake 
the contents thoroughl y. Transfer the clean aqueous layer to a clean test tube by means of a pipette. Add 
one drop of methyl orange solution.  
The residue shall be taken to have passed the test if no pink or red colour is formed.