KENYA STANDARD       DKS 2472:2013  
           
 
 
 
 
 
 
 
 
 
 
 
 
FOOD GRADE HEXANE - SPECIFICATION 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
© KEBS 2012             
  
  
TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were represented on the  Technical Committee: 
 
University of Nairobi 
Agrochemical and Food Company 
Kenyatta University  
KIRDI 
Government Chemist 
MOR – Materials Dept. 
Consumer Information Network  
Spectre International 
Marshall Fowler 
Kel Chemicals 
Associated Battery Manufacturers 
Unilever (K) Ltd 
Pan African 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, K enya Standards shall be regularly reviewed. Suggest ions 
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 sec tion of the Copyright Act, Cap. 12 of 2001 of the L aws 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 with out prior permission in writing 
from the Managing Director.  
 
 
 
 
 
 
 
 
 
  
 KENYA STANDARD                  DKS 2472: 2013  
                  
 
 
 
 
 
 
 
 
 
 
 
 
FOOD GRADE HEXANE - SPECIFICATION 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS) 
 
Head Office:  P.O. Box 54974, Nairobi-00200, Tel.: (+254 020) 60549 0, 602350, Fax: (+254 020)  604031 
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region    Lake Region         Rift Valley Regi on  
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Fax: (+254  041) 229448   Fax: (+254 057) 21814 
 
 
           ©KEBS 
 
 2 Preface  
 
This Kenya Standard was prepared by the Technical C ommittee on Industrial solvents and chemicals under  
the authority of Kenya Bureau of Standards. 
 
Hexane is a hydrocarbon which is a colourless liqui d at room temperature. 
 
Food grade Hexane is mainly used as a solvent in va rious kinds of extraction operations. The formula f or n-
Hexane is CH 3(CH 2)4CH 3. 
 
This Kenya Standard addresses the requirements of f ood grade 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 tha nks: 
 
• IS 3470:2002: - Hexane, Food Grade - Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ©KEBS    DKS 2472:2013 
 
 3 
 
KENYA STANDARD 
 
FOOD GRADE HEXANE - SPECIFICATION 
 
 
 
1. SCOPE 
 
This Kenya Standard specifies requirements and meth ods of test for hexane, food grade, used as a 
 solvent for extraction of oily /oleaginous materia ls.   
 
 
2. REQUIREMENTS 
 
 Food Grade Hexane shall be a petroleum distillate fraction containing a high proportion of n-hexane 
 and shall be clear, colourless liquid with charact eristic petroleum like odour, free from sediment, 
 suspended matter and moisture. Food grade hexane s hall also satisfy the requirements specified in 
 the Table 1 below: 
   
  Table 1: Requirements for Food Grade 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  A nnex A 
3 Density,g/ml at 20 oC 0.660-0.687 KS 1180 
4 Distillation range at 1013 mbar, ºC 
 
IBP 
D.P  
 
63 
95 KS 1180 
5 Refractive Index at 20 oC 1.375-1.384 KS 1180 
6 Residue on evaporation g/100ml,  0.0005 max KS 11 80  
7 Odor Characteristic 
petroleum like 
odour KS 914  
8 Reaction of non-volatile residue Neutral to methy l 
orange Annex B 
 Benzene content, % v/v Max 0.05 KS 2470 Annex C 
 Sulfur, mg/kg, Max  5 KS 2470 Annex F 
9 Lead, as Pb, mg/kg, Max 1 Annex D 
10 Polycyclic aromatic hydrocarbon To pass the test  Annex C 
 
4. MARKING AND PACKING 
 
Food Grade Hexane shall be packaged in suitable and  serviceable containers and marked indelibly 
with the following information: 
 
(a) Name of the product i.e. Food Grade Hexane. 
(b) Manufacturer’s name and/or registered trade mar k; and address 
(c) Country of origin 
(d) Net weight; 
(e) Batch Number 
(f) The words ‘inflammable’ and its Standard Symbol ; 
(g) Date of Manufacture 
(h) Precautionary measures i.e. may cause irritatio n to the eyes, respiratory system and skin.           ©KEBS 
 
 4  
 
 
 
 
 
 
ANNEX  A 
 
DETERMINATION OF COLOUR IN HAZEN UNITS  
(LOVIBOND SCALE) 
 
A.1 PRINCIPLE 
 
Visual comparison of the colour of a sample with th at colour of standards, and expression of the 
result in terms of hazen  
 
Note:For routine control purposes an instrument suc h 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 visua l comparison. 
 
A.2 REAGENTS   
 
Distilled water, or water of equivalent purity, sha ll be used in the test. 
 
A.3 APPARATUS   
 
Ordinary laboratory apparatus and the Lovibond comp arator 
 
A.3.1  Two colorimetric tubes, flat based if possible, wi th 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 a s 50 mL or 100 mL Nessler Cylinders. 
 
For the measurement of low colorations (less than 5 0 Hazen Units), the height of the graduation 
mark above the base must be greater than for the me asurement of deeper colours and must be 
sufficient that, on looking through this greater de pth of liquid, clear distinction between the standa rd 
Hazen matching solutions can be observed.  
 
 
 
NOTE: 1.  For routine control purposes, a colorimetric or sp ectrophotometer may be used, the 
instrument being standardized by means of the stand ard 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 H azen colour units  
 
A.5 TEST REPORT 
 
The test report shall include the following particu lars: 
 
(a) the reference of the method used 
 
(b) the result, expressed in Hazen colour units 
 
(c) any unusual features noted during the determina tion 
 ©KEBS    DKS 2472:2013 
 
 5(d) any operation not included in this standard or regarded as optional. 
 
 
 
 
 
 
Annex B 
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 resi due as in KS 914, add 100ml of distilled water and shake 
the contents thoroughly. 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. 
 
Annex C 
Determination of Polycyclic Aromatic Hydrocarbons 
 
C.1 All glassware should be scrupulously cleaned to rem ove all organic matter such as oil, grease, 
detergent residue and other related materials. Exam ine all glassware including stopper and stopcocks u nder 
ultraviolet light to detect any residual fluorescen t contamination. Rinse all glassware with iso-octan e 
immediately before use because some polynuclear hyd rocarbons sought in this test are susceptible to ph oto-
oxidation. This procedure shall be carried out unde r subdued light. 
 
C.2  Apparatus 
C.2.1 Separatory funnel-125ml capacity equipped wit h tetraflouroethylene (PTFE) polymer stopcocks 
C.2.2 Spectrophotometric cells – fused quartz cells , optical path length in the range of 5.0 ± 0.005 c m.  
C.2.3 Spectrophotometer spectral range of 200-450 w ith spectral slit width of 2nm or less and with  
Wavelength accuracy of ±1.0 and absorbance accuracy  of ±0.05 at 0.4 absorbance. 
 
C.3  Reagents 
 
C.3.1 iso-octane (2,2,4-trimethyl Pentane)- UV spec troscopic grade 
C.3.2 Dimethyl sulphoxide (DMSO) –UV spectroscopic grade 
C.3.3 n-Hexane - UV spectroscopic grade 
C.3.4 Naphthalene  Analytical grade 
 
C.4 Procedure 
C.4.1 Prepare a standard solution of naphthalene in  iso-octane containing 7.0mg of naphthalene per lit re. 
Measure absorbance of the standard solution at 275n m using iso-octane as blank. 
 
C.4.2 Add 25 ml of n-Hexane to a 125ml separating f unnel. Add 5ml of dimethyl sulphoxide. Shake 
vigorously for 1 minute and allow to stand until tw o clear layers are formed. Collect the clear lower layer and 
use as a blank to measure the absorbance of test sa mple 
 
C.4.3 Take two 125ml separating funnels. Transfer 2 5ml of sample to the first 125ml separating funnel and 
add 25ml of n-Hexane. Mix and add 5ml of DMSO. Shak e vigorously for 1 minute and allow to stand until two 
clear layers are formed. 
           ©KEBS 
 
 6 C.4.4 Transfer the lower layer to a second separati ng funnel, add 2ml of n-Hexane and shake the mixtur e 
vigorously. Allow  to stand until two clear layers are formed. Separate the lower layer and measure th e 
absorbance over the range 260nm to 420nm against th e blank. 
 
C.5 At any wavelength in the range 260nm to 420nm, the absorbance of the sample shall not exceed 
one third that of the standard solution at 275nm 
 
 
Annex D 
Determination of Lead 
 
D.1 Introduction 
The sample is treated with bromine, heated on a ste am bath to decompose the alkyl lead and alkyl lead 
salts, and then extracted with dilute nitric acid. The pH of the aqueous extract is adjusted by means of a 
buffer and the lead is extracted with a chloroform solution of dithizone. The absorbance of the chloro form 
extract is measured and the lead content is determi ned from a previously prepared calibration curve. 
 
D.2 Apparatus 
D.2.1 The glassware should be borosilicate and conf irmed to be lead-free. 
D.2.2 Spectrophotometer –Fitted with covered absorp tion cells having a 1 cm light path. 
D.2.3 Shaking machine (optional) capable of approxi mately 250 rpm 
D.2.4 Separatory Funnel -125 ml volume 
 
D.3 Reagents 
D.3.1 Analytical grade reagents and distilled water  shall be used. 
 
D.3.2 Bromine Solution- Dilute300ml of Bromine to 1 000ml with chloroform. Filter through a sintered gl ass 
filter before using. 
 
D.3.3 Buffer Solution –Dissolve 20g of Potassium Cy anide (KCN), 6g of ammonium citrate, and 6g of 
sodium sulphite (Na 2SO 3) separately in water. Mix the solutions, add 150ml  of concentrated ammonium 
hydroxide, (specific gravity 0.90) and dilute to 10 00ml with water. This solution is stable for 3 mont hs (in a 
refrigerator). 
 
D.3.4 Dithizone solution – Dissolve 30mg of Dithizo ne in 1000ml of chloroform. This solution is stable  for 
only 4 weeks. 
 
D.3.5 Lead standard solution – (1ml = 0.005 mg Pb).  Dissolve 1.5985 of lead nitrate [Pb(NO 3)2] in 250ml of 
water contained in a litre volumetric flask. Add 8 ml of concentrated HNO 3 dilute to volume with water..., and 
mix thoroughly. For calibration purposes, pipette 5 .0 ml of this solution into a 1 litre volumetric fl ask, add 8ml 
of concentrated HNO 3 and dilute to volume with water. 
 
D.3.6  Nitric acid-Concentrated nitric acid 
 
D.3.7 Nitric Acid – Mix 8ml of concentrated nitric acid with 992 ml of water. 
 
D.4 Calibration 
 
D.4.1 Prepare a calibration curve using the lead so lution (1 ml = 0.005 mg Pb) as follows: 
Pipette 0.0, 2.0, 5.0, 10.0 and 15.0 ml of the solu tion respectively into each of the five separatory funnels and 
dilute each solution to 50 ml with nitric acid (D.3 .7). Treat these solutions as described in D.5.3 an d D.5.4 
using one not containing lead as a blank. 
 
D.4.2 Construct a calibration curve by plotting the  absorbance of the solution against the mg of lead per 25 
ml dithizone solution. 
 
 
 ©KEBS    DKS 2472:2013 
 
 7D.5 Procedure 
 
D.5.1 Pipette 50g of the sample into a 250ml beaker . Add bromine solution until the bromine colour 
persists for at least 2 minutes, then allow the bea ker to stand for an additional 5 minutes. At the sa me time 
prepare a blank by adding the same amount of bromin e solution to 25.o ml of nitric acid (D.3.7) in a 2 50ml 
beaker. Place the beaker on a steam bath and heat u ntil the bromine colour disappears. Place the beake rs 
on a hot plate and bring the solutions to a vigorou s boil. Cool to room temperature and transfer each solution 
quantitatively, into separating funnels using 25.0 ml of nitric acid (D.3.7). Shake the test sample fo r 2 
minutes. 
 
D.5.2 Drain the aqueous extract of the sample into another separatory funnel. Repeat the extraction of  the 
sample using 25.0 ml of nitric acid (D.3.7). Drain the aqueous layer into the separatory funnel contai ning the 
initial extract. Transfer the blank solution quanti tatively to a 50 ml volumetric flask using 25 ml of  nitric acid 
(D.3.7). Dilute to the mark with water and drain th e contents of the flask into a separatory funnel. 
 
D.5.3 Add 120 ml of the buffer solution to both sep aratory funnels to adjust the Ph to a point between 9.5 
and 11.0. Pipette 25 ml of dithizone solution and s hake for 2 minutes. 
D.5.4 Drain and discard a small portion of the chlo roform layer from the funnel to remove any water or  lead 
that may have accumulated in the stem. Transfer a p ortion of each chloroform layer into separate absor ption 
cells. Adjust the spectrophotometer to read zero ab sorbance for the blank and then measure the absorba nce 
of the sample with respect to the blank at a wavele ngth of 510nm. 
 
D.5.5 Convert the absorbance measurement to concent ration of lead in milligrams of lead per 25 ml of 
Dithizone solution by means of the previously prepa red calibration curve. 
 
D.6 Calculation 
 
Calculate the lead content in mg per Kg as follows:  
 
Lead, mg/Kg = /g2869/g2868/g2868/g3002
/g2873/g2868   = 20A 
 
Where A =Lead concentration, in mg/25ml of dithizon e solution corresponding to the measured absorbance .