FINAL DRAFT UGANDA 
STANDARD  
  FDUS 933
First Edition
2011-mm-dd
 
 
 Reference numbe r
FDUS 933: 2011
© UNBS 2011 
  
Gasohol — Specification for E5 and E10 
 FDUS 933: 2011 
ii © UNBS 2011 – All rights reserved
 Compliance with this standard does not, of itself confer immunity from legal obligations 
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2011  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, in cluding photocopying and microfilm, without prior written 
permission from UNBS. 
Requests for permission to reproduce this document should be addressed to 
The Executive Director 
Uganda National Bureau of Standards 
P.O. Box 6329 
Kampala  
Uganda 
Tel: 256 414 505 995 
Fax: 256 414 286 123 
E-mail: unbs@infocom.co.ug  
Web: www.unbs.go.ug  FDUS 933:2011 
© UNBS 2011 – All rights reserved  iii
 Contents Page 
Foreword ...................................................................................................................... ...................................... vi  
1  Scope ......................................................................................................................... ............................. 1  
2  Normative re ferences .......................................................................................................... .................. 1  
3  Requirements ............................................................................................................................... .......... 2 
3.1  General ....................................................................................................................... ............................ 2  
3.1.1 Anti-oxi dants ................................................................................................................. ......................... 2  
3.1.2 Metal deact ivators ............................................................................................................ ..................... 2  
3.1.3 Dyes .......................................................................................................................... .............................. 3  
3.1.4 Gasoline multifunctiona l additiv es (MFA ....................................................................................... ..... 3 
3.2  Specific requ irements ......................................................................................................... .................. 3  
3.2.1 Quality requirements ............................................................................................................................. 3  
3.2.2 Organic oxyg enates ............................................................................................................ .................. 3  
4  Packing and labelling ......................................................................................................... ................... 4  
4.1  Packing ....................................................................................................................... ............................ 4  
4.2  Labelling ..................................................................................................................... ............................ 4  
5  Sampling ...................................................................................................................... .......................... 4  
Annex A (normative)  Test method for vapour pressure of gasoline- alcohol blend (dry method) .......... 10  
A.1 General ....................................................................................................................... .......................... 10  
A.2 Summary of te st method ........................................................................................................ ............ 10  
A.3 Significance and use .......................................................................................................... ................. 10  
A.4 Reagents ...................................................................................................................... ........................ 10  
A.4.1 Purity of reagents ............................................................................................................ .................... 10  
A.4.2 Acetone ....................................................................................................................... ......................... 10  
A.4.3 Naphtha ....................................................................................................................... ......................... 10  
A.5 Handling of samples ........................................................................................................... ................ 11  
A.6 Preparation for test .......................................................................................................... ................... 11  
A.6.1 Verification of Sample  Container Filling ...................................................................................... ..... 11 
A.6.2 Air saturation of sample in sample container ..................................................................................  11 
A.6.3 Preparation of fuel chamber ................................................................................................... ............ 11  
A.6.4 Preparation of air chamber .................................................................................................... ............. 12  
A.7 Procedure ..................................................................................................................... ........................ 12  
A.7.1 Sample transfer ............................................................................................................... .................... 12  
A.7.2 Assembly of apparatus ......................................................................................................... .............. 12  
A.7.3 Introduction of apparatus into bath ................................................................................................... 12  
A.7.4 Measurement of vapour pressure ...................................................................................................... 12  
A.7.5 Preparation of appara tus for next test ........................................................................................ ...... 13 
A.8 Precauti ons ................................................................................................................... ....................... 14  
A.9 Report ........................................................................................................................ ........................... 14  
A.10 Precision an d bias ............................................................................................................ ................... 14  
A.10.1 Precision ..................................................................................................................... ......................... 14  
A.10.2 Bias .......................................................................................................................... ............................. 15  
Annex B  (normative)  [ Test method for water tolerance (phase separation) of gasoline-alcohol 
blend ......................................................................................................................... ............................ 16  
B.1 General ....................................................................................................................... .......................... 16  
B.2 Summary of te st method ........................................................................................................ ............ 16  
B.3 Significance and use .......................................................................................................... ................. 17  
B.4 Apparatus ..................................................................................................................... ........................ 17  
B.4.1 Test cont ainer ................................................................................................................ ...................... 17  
B.4.2 Thermometers ............................................................................................................................... ....... 17 FDUS 933: 2011 
iv © UNBS 2011 – All rights reserved
 B.4.3 Viton rubber stopper .......................................................................................................... .................17  
B.4.4 Cooling bath .................................................................................................................. .......................17  
B.5 Sampling and handling ......................................................................................................... ..............17  
B.6 Procedure ..................................................................................................................... ........................18  
B.7 Report ........................................................................................................................ ...........................18  
Annex C  (normative)  Determination of MTBE, ETBE, TAME, DIPE, tertiary-amyl alcohol and C1 
to C4 alcohols in gasoline by gas chroma tography ........................................................................19  
C.1 General ....................................................................................................................... ...........................19  
C.2 Terminology ................................................................................................................... ......................19  
C.3 Summary of te st method ........................................................................................................ .............20  
C.4 Significance and use .......................................................................................................... .................20  
C.5 Apparatus ..................................................................................................................... ........................20  
C.5.1 Chromatograph ................................................................................................................. ...................20  
C.5.2 Detector ...................................................................................................................... ..........................22  
C.5.3 Switching and backflushing valve ........................................................................................ .............22  
C.5.4 Automatic valve sw itching device .............................................................................................. .......22 
C.5.5 Injection system .............................................................................................................. .....................22  
C.5.6 Sample in jectors .............................................................................................................. ....................22  
C.5.7 Data presentation or calculation or both ...................................................................................... ....23 
C.5.8 Columns ....................................................................................................................... .........................23  
C.6 Reagents and materials ........................................................................................................ ..............23  
C.6.1 Carrier gas ................................................................................................................... .........................23  
C.6.2 Standards for calibration and identifi cation .................................................................................. ...23 
C.6.3 Methylene ch loride ............................................................................................................ ..................24  
C.7 Preparation of column packings  (TCEP Column  packing) ..............................................................24  
C.8 Preparation of micro-pa cked TCEP column .....................................................................................24  
C.9 Sampling ...................................................................................................................... .........................25  
C.10 Preparation of apparatus and establishment of conditions ............................................................25  
C.11 Calibration and st andardization ............................................................................................... ..........26 
C.11.1 Identification ............................................................................................................................... ..........26 
C.11.2 Preparation of calibration samples ..................................................................................... ................26  
C.11.3 Standardization ............................................................................................................... .....................27  
C.12 Procedure ..................................................................................................................... ........................27  
C.12.1 Preparation of sample ......................................................................................................... ................27  
C.12.2 Chromatographi c analysis ...................................................................................................... ............28  
C.12.3 Interpretation of  chromatogram ................................................................................................ .........28 
C.13 Calculation ............................................................................................................................... .............28  
C.13.1 Mass concentration of oxygenates .............................................................................................. ......28 
C.13.2 Report ........................................................................................................................ ...........................29  
C.14 Precision an d bias ............................................................................................................ ...................29  
Annex D  (normative)  Additional cal culations ................................................................................. .............32  
D.1 Oxygenates content by volume ..........................................................................................................32  
D.2 Total oxygen  content .......................................................................................................... .................32  
Annex E (normative)  Method for determination of ethanol content in 5 % ethanol doped motor 
gasoline by water extraction .................................................................................................. ............34  
E.1  General ....................................................................................................................... ...........................34  
E.2  Outline of the test method .................................................................................................... ..............34  
E.3  Significance and use .......................................................................................................... .................34  
E.4  Chemical re quirements ......................................................................................................... ..............34  
E.4.1 Ethanol/denatured ethanol ..................................................................................................... ............34  
E.4.2 Motor gasoline ................................................................................................................ .....................34  
E.4.3 Ethanol doped mo tor gasoline .................................................................................................. .........34 
E.4.4 Water ......................................................................................................................... ............................35  
E.5  Apparatus ..................................................................................................................... ........................35  
E.6  Calibration on known ethanol content in ethanol  doped motor gasoline and its extraction ......35  
E.7  Procedure ..................................................................................................................... ........................35  
E.8  Calculation ............................................................................................................................... .............35  
E.9  Report ........................................................................................................................ ...........................36  FDUS 933:2011 
© UNBS 2011 – All rights reserved  v
 E.10  Precision a nd bias ........................................................................................................... ................... 36  
 FDUS 933: 2011 
vi © UNBS 2011 – All rights reserved
 Foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 327, of the Laws of Uganda.  UNBS is mandated to co-ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
Committee membership 
The following organisations were represented on the Technical Committee for Petroleum Standards UNBS/TC 
16, in the preparation of this standard: 
• Government Analytical Laboratory 
• Kakira Sugar Limited 
• Kyambogo University 
• Makerere University 
• Ministry Of Energy and Mineral Development 
• Petrocity Enterprises (U) Ltd 
• Shell (U) Ltd 
• Tapuz Group 
• Tullow Uganda Operations Pty Ltd 
• Uganda Industrial Research Institute  
• Uganda National Bureau of Standards 
 FDUS 933:2011 
© UNBS 2011 – All rights reserved  vii
 Introduction 
As a measure of reducing the consumption of gasolines  in spark ignition engines, it has been decided to 
incorporate anhydrous ethyl alcohol  in the fuel consumed by vehicles. FINAL DRAFT UGANDA STANDARD FDUS 933: 2011
 
© UNBS 2011 – All rights reserved  1
 Gasohol — Specification for E5 and E10  
1 Scope 
1.1 This Final Draft Uganda Standard prescribes the requirements and methods of sampling and test for 
blends of gasoline with anhydrous ethyl alcohol (denatur ed fuel ethanol) for use as a fuel in the automobile 
spark ignition internal combustion engines of vehicles. 
Note This standard also may also apply to blends of gasol ine with organic oxygenates such as alcohols and ethers. 
1.2 This standard does not purport to address all of the safety-problems associated with its use. It is the 
responsibility of the user of this  specification to establish appropriate safety and health practices and 
determine the applicability of regulatory limitations prior to use. 
2 Normative references 
The following standards contain provisions which, through re ference in this text, consti tute provisions of this 
standard. At the time of publication the editions indicat ed were valid. All standards are subject to revision, and 
parties to agreements based on the standard are encour aged to investigate the possibility of applying the 
most recent editions of the standards indicated below: 
ASTM E 1, Standard specification for ASTM liquid- in glass thermometers  
ASTM 4815, Standard test method for determination of MTBE, ETBE, TAME, DIPE, tertiary- Amyl alcohol and 
C1 to C4 alcohols in gasoline by gas chromatography  
ISO 2160, Petroleum products corrosiveness to copper strip test  
ISO 3837, Liquid petroleum products — Determination of hydrocarbon types — Fluorescent indicator 
absorption method  
ISO 6246, Petroleum products — Gum content of light and middle distillate fuels — Jet evaporation method  
ISO 4259, Petroleum products — Determination and application of precision data in relation to methods of test 
US 916, Specification for power alcohol for automobile use  
EAS 158, Gasoline (petrol) unleaded — Specification  
ISO 3171, Petroleum liquids — Automatic pipeline sampling  
ISO 3170, Petroleum liquids — Manual sampling  
ISO 3675, Crude petroleum and liquid petroleum products — Laboratory determination of density — 
Hydrometer method   
ISO 12185, Crude petroleum and liquid petroleum pr oducts — Laboratory determination of density — 
Oscillating U-tube method 
US ISO 3405, Petroleum products — Determination of di stillation characteristics at atmospheric pressure  
2 © UNBS 2011 – All rights reserved
 ISO 5164, Petroleum products — Determination of knock char acteristics of motor fuels — Research Method 
ISO 5163, Petroleum products — Determination of knock ch aracteristics of motor and aviation fuels — Motor 
method 
ISO 6246, Petroleum products — Gum content of light and middle distillate fuels — Jet evaporation  
ISO 4260, Petroleum products and hydrocarbons — Determi nation of sulphur content — Wickbold combustion 
method ISO 7536, Gasoline — Determination of oxidation stability of gasoli ne — Induction period method 
ISO 14596, Petroleum products — Determination of sulphu r content — Wavelength- dispersive X-ray 
fluorescence spectrometry ISO 20847, Petroleum products — Determination of sulfur co ntent of automotive fuels — Energy dispersive x- 
ray fluorescence spectrometry  
3 Requirements 
3.1 General 
The gasoline shall be a refined petro leum distillate free from undissolve d water, foreign matter, visible 
impurities and shall conform to EAS 158 . It shall be blended with denatured fu el ethanol that conforms to US 
916. The blend covered by this standard shall be a mixt ure of 5 % v/v, max, denatured ethanol (E5) or 10 % 
by v/v denatured ethanol (E10) with a ppropriate proportion of motor gaso line. It may also contain suitable 
additives  (see 3.1.1 to 3.1.4) in appropriate concentration to  improve the quality of gasoline E10 shall not be 
blended with any other oxygenates for the purposes of stabilizing and/ or as blending components 
NOTE If organic oxygenates are used as blending components  and/or stabilizing agents as  specified in 3.2.2.1the  
amount of such oxygenat es shall comply with the  limiting requirements as spec ified in 3.2.2.2 No other  oxygenates to be 
blended in 10 percent ethanol blended  motor gasoline (E10). 
3.1.1 Anti-oxidants 
Suitable antioxidants may be added in sufficient concentra tion to meet the requirements for oxidation stability 
as specified in Table 1. Some anti-oxi dants of proven chemistry are listed below: 
a) N, N' -disecondary -butyl -paraphenylene diamine; 
b) 2,4-dimethyl-6-tertiary butyl phenol; 
c) 4-methyl-2, 6-ditertiary-butyl phenol; 
d) N, N' - di-isopropyl-paraphenylene diamine; 
e) N-Normal butyl-p-aminophenol; and 
f) mixture of N,N'-disecondary-butylparaphenyle ne diamine and disalicylidene-N-methyl dipropylene 
triamine. 
Addition of anti-oxidants and MFA shall be mandatory for 10 % ethanol blended motor gasoline (E10). 
3.1.2 Metal deactivators 
Suitable metal deactivators shall be added in suffici ent concentration wherever required. Some metal 
deactivators of proven chemistry are listed below: FDUS 933: 2011 
© UNBS 2011 – All rights reserved  3
 a) N,N'-disalicylidene-propylene-diamine; 
b) N,N'-disalicylidene-ethylene diamine; and 
c) N,N'-disalicylidene-methy laminedipropylene- triamine. 
Suitable metal de activators shall be added on sufficient concentration for 10 % ethanol blended motor 
gasoline (E 10). 
3.1.3 Dyes 
A suitable dye as approved by the responsible authority s hall be added in such a proportion so as to satisfy 
the requirements for colour. 
3.1.4 Gasoline multifunctional additives (MFA 
Gasoline multifunctional additives (MFA), other than those mentioned in 3.1.1 and 3.1.2 such as 
detergent/dispersant, rust/corrosion inhibitors an d dehazer additives may be added in appropriate 
concentration to improve the quality of the fuel. Phosphorus containing additives shall not be used. 
3.2 Specific requirements 
3.2.1 Quality requirements The material shall also comply with the requirements prescribed in Table 1 when tested according to the 
methods referred in Table 1. For 10 % ethanol blended mo tor gasoline (E10), the material shall also comply 
with the requirements prescribed in Table 2 when te sted according to the methods referred in Table 2. 
3.2.2 Organic oxygenates 
3.2.2.1 Permitted components 
The following components shall be used either singly or as mixtures as blending components or as stabilizing 
agents to prevent phase separati on of the gasoline/ oxygenate components of the blend: 
a) alcohols 
• isopropyl alcohol (propane-2-ol),  
• butyl alcohol (butane-1-ol),  
• tertiary butyl alcohol (2-methyl-2-propanol),  
• isobutyl alcohol (2-methyl-1-propanol) and  
• other monoalcohols (excluding methanol) with a final boiling point not exceeding 215 °C; 
b) ethers, 
• methyl tertiary butyl ether (MTBE),  
• tertiary amyl methyl ether (methoxy-2-methyl butane) TAME,  
• ethyl tertiary butyl ether (2- ethoxy-2-methyl propane) ETBE and  
• other ethers (R-O-R) with final boiling point not exceeding 215°C and with molecules containing 
five or more carbon atoms. However to avoid t heir dissolution in underground water, measures  
4 © UNBS 2011 – All rights reserved
 should be put into place to ensure that tanks used  for storage of ethers or their blends are secure 
to prevent spillages. 
3.2.2.2 Content 
When tested, the content of the individual component s listed in Table 1 shall comply with the limiting 
requirements as given in Table 1. Mixtures of any of the individual components defined in 3.2.2.1 are 
permitted but the total oxygen content in the gasoline sha ll not exceed 2.7 % by mass and the content of any 
of the individual components given in SI No. (xxi) of Table 1 shall not exceed the corresponding limiting 
requirements. 
4 Packing and labelling 
4.1 Packing 
The material shall be packed in suitable containers to safeguard the contents from contamination and prevent undue evaporation. 
4.2 Labelling 
4.2.1  Each container shall be labelled with the following information: 
a) name and grade of the material; 
b) country of origin 
c) name of manufacturer, init ials or trade-mark, if any; 
d) volume of the contents, in litres; 
e) date  of manufacture or packing; and 
f) caution label 'FLAMMABLE' together with the  sa fety symbols for labelling hazardous substances . 
4.2.2  E5 and E10 meeting quality requirements of Tables 1 and 2 respectively, shall be packaged in 
suitable containers bearing an approved certification mark. The certifying body shall be as approved by 
Ministry of Energy and mineral Development as per the Petroleum Act of 1993. 
5 Sampling 
Representative samples of the material shall be drawn as prescribed in ISO 3170. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  5
 Table 1 — Quality requirements for gasohol blend- E5 
(Clauses 3.2.1, 3.2.2 and 3.2.2.2)  
SI NO Characteristics Units Requirements Method of Test 
Lower limit  Upper limit  
i) Colour,  as decided by 
approving authority as decided by 
approving authority visual 
ii) Density @ 20 ⁰C  kg/m3 720 780 ISO 3675 
ISO 12185 
iii) Distillation 
• Recovery up to 70 ⁰C 
(Evaporation at 70 ⁰C, T-70) percent by 
volume 
• Recovery up to 
100⁰C (Evaporation 
at 100 ⁰C ,T-100) 
percent by volume 
• Recovery up to 
150⁰C (Evaporation 
at 150 ⁰C, T-150) 
percent by volume 
• Final boiling point, 
⁰C 
• Residue, percent by 
volume ºC 
 
 
ºC 
 
 
ºC 10 
 
40 
75 
 
175 45 
 
70 
 
205 
2 ISO 3405 
iv) Research octane 
number, (RON)  91  ISO 5164 
v) Motor octane number 
(MON)  81  ISO 5163 
vi) Existent gum mg/100 mL  0.04 ISO 6246  
vii) Sulphur, total percent by mass  0.15 ISO 4260 
ISO 14596 
ISO 208471) 
viii) Lead content (as pb) g/L  0.015  
ix) Reid vapour pressure 
(RVP) at 38 ⁰C  kPa  67 ISO 3007 (Wet 
method) Annex A 
(Dry method)(see NOTE 1) 
x) Vapour lock index (VLI) 
(VLI = 10 RVP + 7 E70),  (see NOTE 1) kPa  900  
xi) Benzene content percent by 
volume  5 ASTM D 3606 
(ASTM D 5580,  
xii) Copper strip corrosion 
(for 3 h @ 50 ⁰C)   Not more than 1 ISO 2160 
xiii) Water tolerance of 
gasoline-alcohol blends, temperature for phase separation ⁰C  10 Annex B  
6 © UNBS 2011 – All rights reserved
 Table 1 (continued) 
xiv) Engine intake system 
cleanliness (see NOTE 
2)    Report- MFA  used  
xv) Olefin content percent by 
volume  21 ISO 3837 
xvi) Oxidation stability  360  ISO 7536 
xvii) Aromatic content percent by 
volume  42 ISO 3837 
xx) Oxygen content percent by mass  2.7 Annex C and Annex 
D 
xiv) Engine intake system 
cleanliness (see NOTE 2)    Report- MFA  used  
xv) Olefin content percent by 
volume  21 ISO 3837 
xvi) Oxidation stability  360  ISO 7536 
xvii) Aromatic content percent by 
volume  42 ISO 3837 
xx) Oxygen content percent by mass  2.7 Annex C and Annex 
D 
xxi) Oxygenates 
 Methanol percent by 
volume Nil Nil Annex E 
Ethanol (see NOTE 3) percent by 
volume 4.5 - 5.0 
Iso-propyl alcohol percent by 
volume  10 
Iso-butyl alcohol percent by 
volume  10 
Tertiary-butyl alcohol percent by 
volume  7 
Ethers containing 5 or more ‘C’ atoms per molecule percent by 
volume  15 
Other oxygenates (see NOTE 4) percent by 
volume  8 
NOTE 1 For the gasoline-alcohol blends, the dry vapou r test method given in Annex A should be followed. 
NOTE 2 Use of multifunctional additives (MFA) is a require ment for assuring adequate fuel system and intake system 
cleanliness performance in engines. Refiners/marketers of  motor gasoline and its blends have to ensure the MFA2) has 
proper credentials from internationally accepted test laboratori es/authorities, of having passed a minimum of one of the tests 
in each of the two categories of deposit control performance indicated below: 
Deposit Type Test No Test equipm ent Test method Pass limit (Average 
IVD) (Weight) 
Intake Valve Deposit (IVD) 1 BMW IVD Test ASTM D 5500-97 100mg/ valve, max 
 2 MB M102E IVD CEC- O5-A-93 50mg/ valve, max 
 3 FORD 2.3 Litre IVD ASTM D 6201 90 mg/ valve, max FDUS 933: 2011 
© UNBS 2011 – All rights reserved  7
  4 MB M111- IVD Test CEC F-20-A-98 50mg/ valve, max 
Limit (percent injector flow loss) 
Pass limit (percent injector flow loss) 
Port fuel injector 
deposits (PFI) 1 Chysier PFI test ASTM D 5598-95 A 5, max 
 2 PFI  deposit rig ASTM D 6421 10 %, max 
 
Other performance tests may be added as and when they reach qualified/ standard test status. 
NOTE 3 Stabilizing agents may be added. For determinat ion of ethanol content ASTM 05599 or ASTM 04815 shall be 
employed. For routine analysis, method ASTM 0 5845 (FTlR) ur/and water extraction method may he employed (see Annex 
E). 
NOTE 4 Acetone is not permitted except when present as a by-product of the manufa cture of certain oxygenate 
compounds and then only up to 0.8 % (v/v). NOTE 5 All the test methods referred to in this standard incl ude a precision statement. The interpretation of results based 
on test method/ precision shall be used whenever applicable. In case of dispute the procedure described in ISO 4259 should 
be used. 
1)
 In case of dispute, this method shall he the referee method. 
2)MFAs which are certified against National Generic Certification Option as per US EPA-97 final rulc (40 CFR Part 80 certificatio n standards 
for deposit control additives) can also be us ed by fuel refiners/marketers at treatment  levels not less than the Lower Additive s Concentration 
(LAC) limits, as these MFAs meet the criteria for acceptance mentioned above. 
 
Table 1 (completed) 
Table 2 — Quality requirements for 10 % Ethanol blended motor gasoline (E10) 
(Clause 3.2.1) 
SI 
NO Characteristics Units Requirements Method of Test 
Lower limit Upper limit  
ii) Colour,   as decided by 
approving authority  as decided by 
approving authority visual 
iii) Density @ 20 ⁰C,  kg/m3 720 780 ISO 3675 
ISO 12185 
iv) Distillation 
• Recovery up to 70 
⁰C (Evaporation at 
70 ⁰C,T-70) 
percent by volume 
• Recovery up to 
100 ⁰C 
(Evaporation at 
100 ⁰C,T-100) 
percent by volume 
• Recovery up to 
150 ⁰C 
(Evaporation at 150 ⁰C,T-150) 
percent by  10 
 
40 
 
75 
 45 
 
70 
 
 ISO 3405 
 
  
8 © UNBS 2011 – All rights reserved
 volume, min 
• Final boiling point, 
⁰C 
• Residue, percent 
by volume 210 
2 
v) Research octane 
number, RON  91  ISO 5164 
vi) Motor octane number 
(MON), min  81  ISO 5163 
vii) Existent gum g/m3  40 ISO 6246 
viii) Sulphur, total percent by 
mass  0.015 ISO 4260 
ISO 14596 
ISO 20847 
ix) Lead content (as Pb)  g/L  0.005  
x) Reid vapour pressure 
(RVP) at 38 ⁰C (see 
NOTE 1)  kPa  60 
 ISO 3007 (Wet 
method) 
Annex A (Dry 
method)(see note 2) 
xi) Vapour lock index 
(VLI) (VLI = 10 RVP + 7 
E70)   1050 Calculation 
xi) Benzene content,  percent by 
volume  5 ASTM D 5580 
xii) Copper strip corrosion 
(for 3 h at 50 ⁰C)    Not more than 1 ISO 2160 
xiii) Water tolerance of 
gasoline-alcohol blends, temperature for phase separation  ⁰C  10 
 Annex B 
xiv) Engine intake system 
cleanliness (see NOTE 3)   Report- MFA  used  
xv) Olefin content percent by 
volume  21 ISO 3837 
xvi) Oxidation stability  360  ISO 7536 
xvii) Aromatic content percent by 
volume  42 ISO 3837 
xx) Oxygen content percent by 
mass  3.5 Annex C and Annex 
D 
xxi) Oxygenates, ethanol 
(see NOTE 1 and NOTE 4) percent by 
volume 9.50 10 Annex C 
NOTE 1 The dosage of ethanol shall be 9.75 % ± 0.25 % (v/v). 
NOTE  2 For the gasoline-alcohol blends, the dry vapour test method given in Annex A shall be followed. 
NOTE 3 Use of multifunctional additives (MFA) is a require ment for assuring adequate fuel system and intake system 
cleanliness performance in engines. Refiners/Marketers of motor gasoline and its blends have to ensure the MFA2) has 
proper credentials from internationally accepted test laboratories/authorities, of having pass ed a minimum of one of the 
tests in each of the two categories of dep osit control perform ance indicated below: FDUS 933: 2011 
© UNBS 2011 – All rights reserved  9
  
Deposit Type Test No Test Equipment Test Method Pass limit 
(Average IVD) 
(Weight) 
Intake Valve 
Deposit (IVD) 1 BMW IVD Test ASTM D 5500-97 100mg/ valve, max 
 2 MB M102E IVD CEC- O5-A-93 50mg/ valve, max 
 3 FORD 2.3 Litre IVD ASTM D 6201 90 mg/ valve, max 
 4 MB M111- IVD Test CEC F-20-A-98 50mg/ valve, max 
Limit (percent injector flow loss) 
Pass Limit (percent injector flow loss) 
Port fuel injector deposits (PFI) 1 Chysier PFI test ASTM D 5598-95 A 5, Max 
 2 PFI  deposit rig ASTM D 6421 10 %, Max 
 
NOTE 4 Stabilizing agents shall be added. For determinat ion of ethanol content ASTM D 5599 or ASTM D 4815 shall be 
employed. For routine analysis, method ASTM D 5845 (FTIR) may be employed (see
 Annex E). 
NOTE 5 Acetone is not permitted except when present as a by-product of t he manufacture of certain oxygenate 
compounds and then only up to 0.8 percent (v/v).  
NOTE 6 All the test methods referred to in this standard in clude a precision statement. The interpretation of results based 
on test method/ precision shall be used whenever applicable. In case of dispute the procedure described in ISO 4259 shall 
be used. 
NOTE 7  There shall be proper labelling of E1 O (10 percent ethanol blended motor gas oline) fuel at the retail outlets. 
1)
 In case of dispute, this method shall he the referee method. 
2)MFAs which are certified against National Generic Certification Option as per US  EPA-97 final rulc (40 CFR Part 80 certificatio n 
standards for deposit control additives) can al so be used by fuel refiners/marketers at treatment levels not less than the Lowe r Additives 
Concentration (LAC) limits, as these MFAs meet  the criteria for acceptance mentioned above. 
  
10 © UNBS 2011 – All rights reserved
 Annex A 
(normative)  
 
Test method for vapour pressure of gasoline-alcohol blend (dry method) 
A.1 General 
This test method covers the determination of the absolute vapour pressure of gasoline and gasoline-
oxygenate blends. 
NOTE Because the external atmospheric pressure is counteracted by the atmospheric pressure initially present in 
the air chamber, the 'vapour pressure' is an  absolute pressure at 38 °C in kilopas cals. This vapour pressure differs from 
the true pressure of the sample due to some small sample v aporization and the presence of air in the confined space. 
A.2 Summary of test method 
The fuel chamber of the vapour pressure apparatus is filled with the chilled sample and connected to the air 
chamber at 38 °C. The apparatus is immersed in a bath at 38 °C and is shaken periodically until a constant 
pressure is observed on the gauge attached to the apparatus. The gauge reading, suitably corrected, is 
reported as the vapour pressure. 
A.3 Significance and use 
The method cannot be used to determine the vapour pr essure of gasoline-oxygenate blends which contain 
water-extractable oxygenates because the fuel sample comes into contact with water.  
A.4 Reagents 
A.4.1 Purity of reagents 
Use analytical  grade chemicals in all tests. Unless ot herwise indicated, it is in tended that all reagents conform 
to the relevant Uganda standard where such specifications are available.  Other grades may be used, provided 
it is first ascertained that the reagent is of suffici ently high purity to permit its use without lessening the 
accuracy of the determination. 
A.4.2 Acetone 
WARNING - Extremely flammable, Irritating to skin, eyes and mucous membranes. 
A.4.3 Naphtha 
NOTE Naphtha [Tag closed cup flash point below -6°C]. 
WARNING - Extremely flammable. Harmful if inhaled. Skin irritant on repeated contact. Aspiration hazard. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  11
 A.5 Handling of samples 
A.5.1  The extreme sensitivity of vapour pressure measurements to losses through evaporation and the 
resulting changes in composition is such as to require the utmost precaution and the most meticulous care in 
the handling of samples. The provisions of this clause apply to all samples for vapour pressure 
determinations. 
A.5.2  Sample in accordance with ISO 3170.  
A.5.3  The size of the sample container from which the vapour pressure sample is taken as 1 L. It will be 70 
% to 80 % filled with the sample. A.5.4  Precautions in A.5.4.1 – A.5.4.4 shall be observed. 
A.5.4.1  Determine vapour pressure as the first test run on a sample. Do not withdraw more than one 
sample from the sample container for this test. A.5.4.2  Protect samples from excessive heat prior to testing. 
A.5.4.3  Do not test samples in leaky containers. Discard them and obtain new samples. 
A.5.4.4  Discard samples that have separated into two phases and obtain new samples (see
 Note 2 under 
A.7.3). 
A.5.5  In all cases, cool the sample container and contents  to 0 °C to 1 °C before the container is opened. 
To ensure sufficient time to reach this temperature, di rectly measure the temperatur e of a similar liquid in a 
container placed in the cooling bath at the same time as the sample. 
A.6 Preparation for test 
A.6.1 Verification of sample container filling 
A.6.1.1  With the sample at a temperature of 0 °C to 1 °C, take the container from the cooling bath, wipe 
dry with an absorbent material, unseal it, and examine its ullage. The sample content, as determined by use of 
a suitable gauge, shall be equal to 70 % to 80 % of the container capacity. 
A.6.1.2  Discard the sample if its volume is less than 70 % of the container capacity. 
A.6.1.3  If the container is more than 80 % full, pour out enough sample to bring the container contents 
within the 70 % to 80 % range. Under no circum stances, may any sample poured out, be returned to the 
container. 
A.6.2 Air saturation of sample in sample container 
A.6.2.1 With the sample again at a temperature of o to 1°C take the container from the cooling bath, 
wipe it dry with an absorbent material, unseal it momentarily, taking care to prevent water entry, reseal it, and 
shake it vigorously. Return it to the bath for a minimum of 2 min. 
A.6.2.2 Repeat A.7.2.1 twice more. Return the sample to  the bath and keep it there until the beginning of 
the procedure (see A.7). 
A.6.3 Preparation of fuel chamber 
Observe the apparatus preparation procedure of A.7.5, then store the stopper ed fuel chamber and the sample 
transfer connection in a refrigerator or ice-water bath  for a sufficient time to allow the chamber and the 
connection to reach a temperature of 0 °C to 1 °C. If and ice-water bath is used, keep the chamber upright  
12 © UNBS 2011 – All rights reserved
 and not immersed over the top of the co upling threads. The transfer connecti on is inserted over the top of the 
coupling threads. The transfer connection is inserted into a plastic bag to keep it completely dry during 
cooling. 
A.6.4 Preparation of air chamber 
Observe the apparatus preparation proc edure of A.7.5. Connect the gauge to the air chamber and close the 
lower opening securely with a dry No.6 rubber stopper . Make sure the stopper is inserted far enough to 
securely close the vent hole in the air chamber connec tion. Immerse the air chamber to at least 25 mm above 
its top in the water bath until the fuel chamber ha s been filled with the sample as described in A.7.1. 
A.7 Procedure 
A.7.1 Sample transfer 
With everything in readings, remove the chilled sample co ntainer from the bath, dry it with absorbent material, 
uncap it, and dry and insert the chilled transfer apparatus (see  Figure 1). Quickly place the chilled fuel 
chamber, in an inverted position, over the sample de livery tube of the transfer apparatus. Invert the entire 
system rapidly so that the fuel chamber is upright, wi th the end of the delivery tube touching the bottom of the 
fuel chamber. Fill the fuel chamber to the overflowing. Withdraw the deliver y tube from the fuel chamber while 
allowing the sample to continue flowing up to the moment of complete withdrawal. 
CAUTION - Make provision for suitable collection and disp osal of the overflowing fuel to avoid fire hazard. 
A.7.2 Assembly of apparatus 
Immediately remove the air chamber from the water bath and immediately dry the exterior of the chamber with 
absorbent material giving particular care to the con nection between the air chamber and the fuel chamber. 
Remove the stopper after drying and immediately couple the two chambers. Not more than 10 s shall be 
consumed in coupling the two chambers. 
NOTE  When the air chamber is removed from the water bath  and is dried, and the stopper removed, connect it to 
the fuel chamber without undue movements through the air, which could promote ex change of room temperature air with 
the 38 °C air in the chamber. 
A.7.3 Introduction of apparatus into bath 
Turn the assembled vapour pressure apparatus upside dow n to allow the sample in the fuel chamber to run 
into the air chamber. With the apparatus still inverted, shak e it vigorously eight times in a direction parallel to 
the length of the apparatus. With the gauge end up, immerse the assembled apparatus in the bath, 
maintained at 38 °C ± 0.1 °C in an inclined position so that the connection of t he fuel and air chambers is 
below the water level and may be carefully examined for leaks 25 mm above the top of the air chamber. 
Observe the apparatus for leakage throughout the test. Discard the test at any time a leak is detected. 
NOTE 1 Liquid leaks are more difficult to detect than vapour leaks, and because the coupling between the chambers is 
normally in the liquid section of the apparatus  give the coupling particular attention. 
NOTE 2 After the apparatus has been immersed in the bath check the remaining sample for phase separation. If the 
sample is contained in a glass container, this observation can be made prior to sample transfer (see A.7.1) . If the sample 
is contained in a non-transparent  container, shake the sample vigorously for 5 s and then immediately pour a portion of 
the remaining sample into a clear glass container. Immediately after shaking this sample again for 5 s, observe the sample 
for phase separation. If this sample is not clear and bright, and free of a second phase, discard the test and the sample. 
A.7.4 Measurement of vapour pressure 
After the assembled vapour pressure apparatus has been immersed in the bath for at least 5 min, tap the 
pressure gauge lightly and observe the reading. Withdr aw the apparatus from the bath and repeat A.7.3. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  13
 
 
Figure 1 — Simplified sketches outlining method of transferring samples to gasoline chamber from 
open- type containers 
At intervals of not less than 2 min,  perform A.7.3 until a total of not less than five shakings and gauge readings 
have been made continue thereafter, if necessary, until the last two cons ecutive gauge readings are constant, 
indicating equilibrium attainment. These operations normally require 20 min to 30 min. Read the final gauge 
pressure to the nearest 0.25 kPa for gauges with interm ediate graduations of 0.5 kPa or less than to the 
nearest 0.5 kPa for gauges with graduations of 1.0 kPa to 2.5 kPa and record the values as the 'uncorrected 
vapour pressure' of the sample. Without undue delay remo ve the pressure gauge and, without attempting to 
remove any liquid which may be trapped in the gauge, check its reading against that  of the manometer while 
both are subjected to a common steady pressure which is no more than 1.0 kPa .different from the recorded 
'uncorrected vapour pressure'. If a difference is ob served between the gauge and manometer readings, the 
difference shall be added to or subtracted from the 'un corrected vapour pressure' recorded for the sample 
being tested, and the resulting value shall be reco rded as the vapour pres sure of the sample.  
NOTE  1 Cooling the assembly prior disconnecting the g auge will facilitate, disassembl y and reduce the amount of 
hydrocarbon vapour released into the room. 
NOTE 2 Verification of sample integrity  Disconnect the air chamber from the fuel chamber. Drain the sample from the air and fuel chambers as completely as 
possible into a dry (8-oz) 240 ml clear glass bottle. Seal the bottle and shake it vigorously for 5 s. If the sample is clear a nd 
bright and free of a second phase, note this observation and record  the test is valid. If the sample is not clear and bright 
and free of second phase. Immerse the bottl e in the 38°C water bath up to about 25 mm above the top of the sample level 
for 15 min in order to heat the sample to the test temperat ure. Remove the sample from the water bath and immediately 
shake it vigorously for 5 s and observe the sample. If the samp le is not clear and bright and free of second phase, note 
this observation and record that the test is not valid because of phas e separation. A fuel that is not clear and bright and 
free of second phase at this point of the test indicates that the fuel was contacted with sufficient water to exceed the water tolerance of the fuel during the test procedure. Water can mo st likely get into the test ch ambers during preparation of the 
fuel and air chambers (see A.6.3 and A.6.4) or assembly of the air and fuel chambers (see A.7.2), or both, specially and 
fuel chambers (see A.7.2), or both specially if water baths are used for these procedures. 
A.7.5 Preparation of apparatus for next test 
Thoroughly purge the air chamber of residual sa mple by filling it with warm water above 32 °C  and allowingit 
to drain. Repeat the purging at least five times. Af ter disconnecting the pressure gauge from its manifold 
connection with the manometer, remove trapped centrifugal thrusts. This may be accomplished in the 
following manner, hold the gauge between the palms of the hands with the right hand on the face side and the  
14 © UNBS 2011 – All rights reserved
 threaded connection of the gauge forward. Extend the arms forward and upward at an angle of 45°, with the 
coupling of the gauge pointing in the same direction. Swing the arms downward through an arc of about 135° 
so that the centrifugal force aids gravity in removing the trapped liquid. Repeat this operation three times to 
expel all liquid. Purge the pressure gauge by directing a sma ll jet of air into its Bourdon tube for at least 5 min. 
Rinse both chambers and the sample transfer connecti on several times with petroleum naphtha, then several 
times with acetone, then blow dry using dried air. Stopper the fuel chamber and place it in the refrigerator or 
ice-water bath for the next test. 
NOTE If the purging of the air chamber is done in a bath, be sure to avoid small and unnoticeable films of floating 
sample by keeping the bottom and top opening of the chamber closed as they pass through the water surface. 
A.8 Precautions 
Gross errors can be obtained in vapour pressure meas urements, if the prescribed procedure is not followed 
carefully. The following list emphasizes the importance of strict adherence to the precautions given in the 
procedure. 
a) Check all gauges against a manometer after each test in order to ensure high precision of results (see 
A.7.4). Read all gauges while the gauges are in a vertical position and after tapping them lightly. 
b) Shake the container vigo rously to ensure equilibri um of the sample with the air in the container (see 
A.6.2). 
c) Check the apparatus before and during each test for both liquid and vapour leaks. 
d) Because initial sampling and the handling of samples will greatly affe ct the final results, employ the 
utmost precaution and the most meticulous care to  avoid losses through evaporation and even slight 
changes in composition (see A.5.5 and A.7.1). In no case shall any part of the apparatus itself be 
used as the sample container prio r to actually conducting the test. 
e) Thoroughly purge the pressure gauge, the fuel cham ber and the air chamber to be sure they are free 
of residual sample. [This is most convenient ly done at the end of the previous test (see  A.7.5)]. It is 
important to remove all water from the apparatus before cooling the gasoline chambers and heating 
the air chamber. In high humidity conditions be alert for and avoid condensation on the transfer 
connection and interior walls of the apparatus. 
A.9 Report 
Report to the nearest 0.25 kPa or 0.5 kPa the gauge resu lt observed in A.7.4, after correcting for any 
difference between the gauge and manometer, as the vapour pressure in kilopascals without reference to temperature
. 
A.10 Precision and bias 
A.10.1 Precision 
The following criteria should be used for judging the acceptability of results (95 % confidence). 
A.10.1.1 Repeatability 
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 the fo llowing value only in one case in twenty: 
Component       Repeatability FDUS 933: 2011 
© UNBS 2011 – All rights reserved  15
 Guage Range      kPa 
0 to 100 kPa       4.90 
A.10.1.2 Reproducibility 
The difference between two single and independent results, obtained by different operators working in 
different laboratories on identical test material would, in the long run, in the normal and correct operation of 
the test method, exceed the following value only in one case in twenty . 
Component       Repeatability 
Guage Range      kPa 
0 to 100 kPa       7.790 
A.10.2 Bias 
There being no criteria for measuring bias in these test product combinations, no statement of bias can be 
made.  
16 © UNBS 2011 – All rights reserved
 Annex B  
(normative)  
[ 
Test method for water tolerance ( phase separation) of gasoline-alcohol 
blend 
B.1 General 
This test method determines the ability of gasoline-oxygenate blends to retain water in solution or in a stable 
suspension at the lowest temperature to wh ich they are likely to be exposed in use. 
B.2 Summary of test method 
The sample of fuel is cooled at a controlled rate to its expected use temperature and is periodically observed 
for both haze and phase separation. The apparatus as s hown below, a dry ice-isopropyl alcohol bath may be 
used. A maximum cooling rate of 2 °C/mm  is specified because phase separation in gasoline-oxygenate 
blends has a relatively long but unpredictable induction period. 
Dimensions in millimetres 
 
Figure 1 — Apparatus for test method FDUS 933: 2011 
© UNBS 2011 – All rights reserved  17
 B.3 Significance and use 
B.3.1  Some oxygenate-containing fuels,  and gasoline-alcohol blends in par ticular have a very limited ability 
to retain water in solution or in stable suspension, and if the amount of water in the blend exceeds this limit, 
the fuel will separate into a lo wer oxygenate-rich aqueous phase and an upper oxygenate-lean hydrocarbon 
phase. The most important fact or governing the ability of a sp ecific fuel to retain water without such separation 
is its temperature. This method is intended to determine the maximum temperature at which the fuel will 
separate. The temperatures represent the maximum temperatures above which the fuel must not separate 
into two distinct phases. 
B.3.2  Note that in this test, actual separation of the samp le into two distinct phases is the criterion for failure. 
The following are indications of phase separation. 
B.3.2.1  The formation of droplets large enough to be detected by the unaided eye. They may be either 
clinging to sides of the container or collect on the bottom. 
B.3.2.2  The formation of two layers separated by ei ther common boundary, or a layer of emulsion. 
Formation of haze without one of these indication s of separation is not cause for rejection. 
B.4 Apparatus 
B.4.1 Test container  
Any glass container of about 100 mL capacity may be used. This container may be marked at the level of 40 
mL. 
B.4.2 Thermometers  
Meeting the requirements of Specification ASTM E1, ASTM thermometer 6 °C (range -80 °C to +20 °C, 1 °C 
graduations, 76 mm immersion. 
Thermometer 6 °F is the Fahrenheit equivalent of 6 °C, spans the necessary range of temperatures. A 
thermometer shall be provided for each container, mounted to pass through the stopper. 
B.4.3 Viton rubber stopper  
To fit sample container bored centrally for the test thermometer . 
B.4.4 Cooling bath  
Shall be provided with a jacket disk and gasket (as sp ecified in the apparatus section) filled with an equal-
volume mixture of water and 'Permanent' anti-freeze and provided with refrigeration coils capable of reducing 
its temperature to - 40 °C. Alternatively, a dry ice-isopropyl alcohol bath may be used. 
B.5 Sampling and handling 
B.5.1  Draw samples in accordance with ISO 3171 
B.5.2  Draw the samples in steel cans that have been solvent washed. 
B.5.3  Store the samples in refrigerator (2 °C to 7 °C) whenever not actually transferring sample. 
B.5.4  Because gasoline-alcohol blends are hygroscopic as well as volatile, minimize contact with the 
atmosphere by keeping sample containers tightly closed except when transferring sample.  
18 © UNBS 2011 – All rights reserved
 B.6 Procedure 
B.6.1  Warm the sample to 15 °C and shake, to re-dissolve any water that may have settled out at the 
refrigerator temperature. 
B.6.2  Cool the test container to 10 °C to 15 °C. Carry out steps B.6.3 through B.6. 5 as promptly as possible 
to minimize vaporization losses and absorption of water from the atmosphere. 
B.6.3  Rinse out the cooled test container with some of the sample to be tested. Drain. 
B.6.4  Pour about 40 mL of the sample into the test contai ner. The precise amount is not critical, but it must 
be enough to submerge the thermometer bulb adequately, without being so much as to require an excessive 
amount of cooling time. If the sample has separat ed, as defined in B.3.2, terminate the test. 
B.6.5  Seal the test container with the rubber stopper . Locate the thermometer bulb approximately at the 
centre of the fuel sample. B.6.6   Cool the sample by intermittent immersion in or circulation of the coolant. The sample is not to be 
swirled or shaken while in the cooling bath. Starting at a cooling bath temperature not higher than 10 °C or 16 
°C above the test temperature, cool the sample at a maximum rate of 2 °C/min until phase separation occurs, 
or the test temperature is reached. 
B.6.7  At 2 °C intervals, remove the test container from the cooling bath and shake vigorously for 5 s to 10 s. 
Wipe the exterior of the sample container with a towel moistened with isopropyl alcohol to remove any 
condensation, and observe the condition of the sample for no more than 5s against a light coloured 
illuminated background. 
B.6.8  It is likely that the sample will get hazy prior to actual phase separation as defined in B.3.2. Record 
the sample temperature at the first indication of ha ze (when cooling); and the temperature when the haze 
disappears (warming). B.6.9  Record the temperature of phase separation (see
 B.3.2). Then allow the sample to warm at ambient 
temperature. Shake the sample vigorously after a temperature rise of 2 °C, and observe. Record a 'warming' 
phase recombination temperature, and the haze disa ppearance temperature. Average these 'cooling' and 
'warming' temperatures to determine the actual phase separation and haze point temperatures. Repeat this 
process for improved accuracy. 
B.7 Report 
Report the averaged haze point and phase s eparation temperatures found in B.6.9. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  19
 Annex C  
(normative) 
 
Determination of MTBE, ETBE, TAME, DIPE, tertiary-amyl alcohol and C1 
to C4 alcohols in gasolin e by gas chromatography 
C.1 General 
C.1.1  This test method stipulates a procedure for deter mination of alcohols (methanol, ethanol, isopropanol, 
n-propanol, isobutanol, sec-butanol, tertbutanol, n-but anol, tert-pentanol) and ethers (MTBE, ETBE, TAME, 
DIPE) in gasoline by gas chromatography. 
C.1.2  Individual alcohol are determined from 0.1 mass percent to 12.0 mass percent and individual ethers 
are determined from 0.1 to 20.0 mass percent. Equati on used to convert to mass percent oxygen and to 
volume percent of individual compounds are available. 
C.2 Terminology 
C.2.1 
low volume connector   
special union for connecting two lengths of tubing 1.6 mm inside diameter and smaller. Sometimes this is 
referred to as a zero dead volume union. 
C.2.2 
MTBE   Methyl Tertiary-Butyl Ether 
C.2.3 
ETBE 
Ethyl Tertiary-Butyl Ether 
 
C.2.4 
TAME 
Tertiary-Amyl Methyl Ether 
C.2.5 
DIPE  
Diisopropyl Ether 
C.2.6 
tertiary-amyl alcohol 
tertiary-pentanol 
C.2.7 
oxygenates  
any oxygen-containing organic comp ounds which can be used as a fuel or fuel supplement, for example 
various alcohols and ethers 
C.2.8 
split ratio  term used in gas chromatogra phy using capillary co lumns. The split ratio is the ratio of the total flow of the 
carrier gas to the sample inlet versus the flow of carrier gas to the capillary column expressed by:  
20 © UNBS 2011 – All rights reserved
 Split ratio = 
CC S+ 
where 
S is the flow rate at the splitter vent, and 
C is the flow rate at the column outlet. 
C.2.9 
TCEP  
1,2,3-Tris-2-Cyanoethoxypropane-a  gas chromatographic liquid phase 
C.2.10 
WCOT  
type of capillary gas chromatographic column prepared by c oating the inside of the capillary with a thin film of 
stationary phase 
C.3 Summary of test method 
An appropriate internal standard such as 1,2-dimeth oxy ethane (ethylene glycol dimethyl ether) is added to 
the sample which is then introduced into a gas chromatograph equipped with two columns and a column 
switching valve. The sample first passes into a polar TCEP column which elutes lighter hydrocarbons to vent and retains the oxygenated and heavier hydrocarbons. After methylcyclopentane, but before DIPE and MTBE 
elute from the polar column, the valve is switched to backflush the oxygenates onto a WCOT non-polar 
column. The alcohols and ethers elute from the nonpolar column in boiling point order, before elution of any 
major hydrocarbon constituents. After TAME and benz ene elute from the non-polar column, the column 
switching valve is switched back to its original po sition to backflush the heavy hydrocarbons. The eluted 
components are detected by a flame ionization or ther mal conductivity detector. The detector response, 
proportional to the component concentration, is recorded; the peak areas are measured; and the 
concentration of each component is calculated with reference to the internal standard. 
C.4 Significance and use 
C.4.1  Ethers, alcohols and other oxygenates may be adde d to gasoline to increase the octane number and 
to reduce emissions. Type and concentration of vari ous oxygenates are specified and regulated to ensure 
acceptable commercial gasoline quality. Drivabilit y vapour pressure, phase separation exhaust and 
evaporative emissions are some  of the concerns associ ated with oxygenated fuels. 
C.4.2  This test method is applicable to both quality control in the production of gasoline and for the 
determination of deliberate or extraneou s oxygenate additions or contamination . 
C.5 Apparatus 
C.5.1 Chromatograph 
C.5.I.1  While any gas chromatographic system, which is  capable of adequately resolving the individual 
ethers and alcohols, can be used for these analyses,  a gas chromatographic instrument which can be 
operated under the conditions given in Table 3 and having a column switching and back flushing system 
equivalent to Figure 2 has been found acceptable. Carr ier gas flow controllers shall be capable of precise 
control where the required flow rates are low (see  Table 3). Pressure control devices and gauges shall be 
capable of precise control for the typical pressures required. 
 FDUS 933: 2011 
© UNBS 2011 – All rights reserved  21
 
 
Figure 2 — Analysis of oxygenates in gasoline schematic diagram/ representation of chromatographic 
system  
22 © UNBS 2011 – All rights reserved
  
Table 3 — Chromatographic operating conditions 
SI No Temperatures Flows, ml/ min Carrier Gas: Helium 
(1) (2) (3) ( 4) (5) (6) (7) 
i) Column oven, °C 60 To injector 75 Sample size, microlitre 1.0 - 3.0 
ii) Injector. °C 200 Column 5 Split ratio 15:1 
iii) Detector 
a) TCD, °C 200 Auxillary 3 Backflush, min 0.2 - 0.3 
b) FID, °C 250 Makeup 18 Valve reset time 8 min - 10 min 
iv) Valve, °C 60   Total analysis time 18 min -20 min 
 
C.5.2 Detector 
A thermal conductivity detector or flame ionization de tector, may be used. The system shall have sufficient 
sensitivity and stability to obtain a record er deflection of at least 2 mm at a signal-to-noise ratio of at least 5 to 
1 for 0.005 volume percent concentration of an oxygenate. 
C.5.3 Switching and backflushing valve 
A valve, to be located within the gas chromatogra phic column oven, capable of performing the functions 
described in C.10 and illustrated in Fig. 2. The valve shall be of low volume design and not contribute 
significantly to chromatographic deterioration. 
C.5.3.1 Valco Model No. A 4C10WP, 1.6 mm fittings 
This particular valve has been used in the majority  of the analyses used for the development of C.14. 
C.5.3.2 Valco Model No. C10W, 0.8 mm fittings  This valve is recommended for use with columns of 0.32 mm inside diameter and smaller.  
C.5.4 Automatic valve switching device 
An automatic valve switching device shall be used to ensure repeatable switching times. Such a device shall 
be synchronized with injection and data collection times . 
C.5.5 Injection system 
The chromatograph should be equipped with a splitting-type inlet device if capillary column or flame ionization 
detection is used. Split injection is necessary to main tain the actual chromatographed sample size within the 
limits of column and detector optimum efficiency and linearity . 
C.5.6 Sample injectors 
Any system capable of introducing a representative samp le into the split inlet dev ice. Microlitre syringes, 
automatic syringe injectors, and liquid sampling valves may be used. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  23
 C.5.7 Data presentation or calculation or both 
C.5.7.1 Recorder 
A recording potentiometer or equivalent with a full scale deflection of 5 mV or less is used. Full-scale response 
time should be 1 s or less with sufficient sensitiv ity and stability to meet t he requirements of C.5.2. 
C.5.7.2 Integrator or computer Devices capable of meeting the requi rements of C.5.2 and providing graphi c and digital presentation of the 
chromatographic data are recommended for use. Mean s shall be provided for determining the detector 
response. Peak heights or areas can be measured by computer, electronic integration or manual techniques. 
C.5.8 Columns 
C.5.8.1 Polar column This column performs a preparation of  the oxygenates from volatile hydr ocarbons in the same boiling point 
range. The oxygenates and remaining hydrocarbons are back flushed onto the non-polar column in C.5.8.2. 
Any column with equivalent or better chromatographic e fficiency and selectivity to that described in C.5.8.1.1 
can be used. The column shall perform at the same temperature as required for the column in C.5.8.2. 
C.5.8.2 TCEP micro-packed column 
560 mm by 1.6 mm outside diameter by 0.38 mm inside diameter stainless steel tube packed with 0.14 g to 
0.15 g of 20 % (mass/mass) TCEP on 80/100 mesh chro mosorb P (AW). This column was used in the 
cooperative study to provide the precis ion and bias data referred to in C.14. 
C.5.8.3 Non-polar (analytical) column 
Any column with equivalent or better chromatographic e fficiency and selectivity to that described in C.5.8.2.1 
and illustrated in Figure 3 can be used. 
C.5.8.4 WCOT methyl silicon column 
30 m long by 0.53 mm inside diameter, fused silica WCOT co lumn with a 2.6 µrn film thickness of cross linked 
methyl siloxane. This column was used in the operativ e study to provide the precision and bias data referred 
to in C.14. 
C.6 Reagents and materials 
C.6.1 Carrier gas  
Carrier gas appropriate to the type of detector used. Helium has been used successfully. The minimum purity 
of the carrier gas used shall be 99.95 mol percent. 
C.6.2 Standards for calibration and identification 
Standards of all components to be analyzed and the internal standards are required for establishing 
identification by retention time as well as calibration for quantitative measurements. These materials shall be 
of known purity and free of the other components to be analyzed. 
WARNING - These materials are flammable and ha rmful or fatal if ingested or inhaled.  
24 © UNBS 2011 – All rights reserved
 C.6.3 Methylene chloride 
Used for column preparation. Reagent grade shall be free of non-volatile residue. 
WARNING - Harmful if inhaled. High concentr ation may cause unconsciousness or death. 
C.7 Preparation of column packings (TCEP Column packing) 
Any satisfactory method, used in the practice of the ar t that will produce a column capable of retaining the Cl 
to C 4 alcohols and MTBE, ETBE, DIPE and TAME from co mponents of the same boiling point range in a 
gasoline sample. The following procedure has been used successfully: 
 
Figure 3 — Analysis of oxygenates in gasoline example chromatogram showing oxygenates 
Completely dissolve 10 g of TCEP in 100 mL of methylene chloride. Next add 40 g of 801100 mesh 
Chromosorb P (AW) to the TCEP solution. Quickly transfe r this mixture to a drying dish, in a fume hood, 
without scraping any of the residual packing from the sides of the contai ner constantly, but gently, stir the 
packing until all of the solvent has evaporated. This column packing can be used immediately to prepare the 
TCEP column. 
C.8 Preparation of micro-packed TCEP column 
C.8.1  Wash a straight 560 mm length of 1.6 mm outside di ameter (0.38 mm inside di ameter) stainless steel 
tubing with methanol and dry with compressed nitrogen. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  25
 C.8.2   Insert 6 to 12 strands of silvered wire, a small mesh screen or stainless steel fr it inside one end of the 
tube. Slowly add 0.14 g to 0.15 g of packing material to the column and gently vibrate to settle the packing 
inside the column. When strands of wire are used to reta in the packing material inside the column, leave 6.0 
mm of space at the top of the column . 
C.8.3  Both the TCEP and WCOT columns are to be briefly conditioned before use. Connect the columns to 
the valve (see  C.10.1) in the chromatographic oven. Adjust the carrier gas flows as in C.10.3 and place the 
valve in the RESET position. After several minutes, increase the column oven temperature to 120 °C and 
maintain these conditions for 5 min to 10 min, cool the columns below 60 °C before shutting off the carriers 
flow. 
C.9 Sampling 
Gasoline samples to be analysed by this test method shall be sampled using procedures stipulated in ISO 
3171. 
C.10 Preparation of apparatus a nd establishment of conditions 
C.10.1 Connect the WCOT column to the valve system us ing low volume connectors and narrow bore tubing. 
It is important to minimize the volume of the chromat ographic system that comes in  contact with the sample, 
otherwise peak broadening will occur. 
C.10.2  Adjust the operating conditions to those listed in  Table 3, but do not turn on the detector circuits. 
Check the system for leaks before proceeding further. 
C.10.3  Attach a flow measuring device to the column vent with the valve in the RESET position and adjust 
the pressure to the injection port to give 5.0 mL/min flow. Soap bubble flow meters are suitable. 
Attach a flow measuring device to the split injector vent and adjust the flow from the split vent using the A (see 
Fig. 2) flow controller to give a flow of 70 ml/min . Recheck the column vent flow set above and adjust, if 
necessary. 
Switch the valve to the BACKFLUSH position and adjust th e variable restrictor to give the same column vent 
flow set initially. This is necessary to minimize flow changes when the valve is switched . 
Switch the valve to the inject po sition RESET and adjust the B (see  Figure 2)  flow controller to give a flow of 
3.0 mL/min to 3.2 mL/min at the detector exit. When required for the particular instrumentation used, add 
makeup flow or TCD switching flow to give a total of 21 mL/min at the detector exit. 
C.10.4  When a thermal conductivity detector is used, turn  on the filament current and allow the detector to 
equilibrate. When a flame ionization detector is used, set the hydrogen and air flows and ignite the flame . 
C.10.5  The time to backflush will va ry slightly for each column system and shall be determined 
experimentally as follows. The start time of the int egrator and valve timer shall be synchronized with the 
injection to accurately reproduce the backflush time. 
Initially assume a valve BACKFLUSH time of 0.23 mi n. With the valve RESET, inject 3 µL of a blend 
containing at least 0.5 % of greater oxygenates (see  C.6.3), and simultaneously begin timing the analysis. At 
0.23 min, rotate the valve to the BACKFLUSH position and leave it there until the co mplete elution of benzene 
is realized. Note this time as the RESET time, which is  the time at which the valve is returned to the RESET 
position. When all of the remaining hydrocarbon is ba ckflushed the signal will return to a stable baseline and 
the system is ready for another analysis. The chromatogr am should appear similar to that illustrated in Figure 
3. 
It is necessary to optimize the valve BACKFLUSH time by analyzing a standard bl end containing oxygenates. 
The correct BACKFLUSH time is determined experimentally by using valve switching times between 0.2 and 
0.3 min, when the valve is switched too soon, C 5 and lighter hydrocarbons are backflushed and are co-elluted  
26 © UNBS 2011 – All rights reserved
 in the C 4 alcohol section of the chromatogram. When the valve BACKFLUSH is switched too late, part of all of 
the ether components (MTBE, ETBE or TAME) is vented resulting in an incorrect MTBE measurement. DTPE 
may require a BACKFLUSH time slightly shorter than the other ethers. The system may require 
reoptimization, if analysis of DIPE is required. 
C.11 Calibration and standardization 
C.11.1 Identification 
Determine the retention time of each component by in jecting small amounts either separately or in known 
mixtures or by comparing the relative retention times with those in Table 4. 
In order to ensure minimum interference from hydrocar bons, it is strong ly recommended that a fuel devoid of 
oxygenates be chromatographed to determine t he level of any hydrocarbon interference. 
NOTE Chromatographic operating conditions shall be set as in Table 3. 
C.11.2 Preparation of calibration samples 
Prepare multi-component calibration standards of the o xygenates and concentration ranges of interest by 
mass. For each oxygenate, prepare a minimum of fi ve calibration standards spanning the range of the 
oxygenate in the samples. As an example, for full ran ge calibration, 0.1, 0.5, 2,  5,10,15 and 20 mass percent 
of each oxygenate may be used. Before  preparing the st andards, determine the purit y of the oxygenate stocks 
and make corrections for the impurities found. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  27
 Table 4 — Retention characteristics for TCEP/ WCOT column 
SI No Component Retention Time, Min Relative Retention Time 
   (MTBE= 1.00) (DME=1.00) 
(1) (2) (3) (4) (5) 
i) Methanol 3.15 0.63 0.46 
ii) Ethanol 3.48 0.69 0.51 
iii) Isopropanol 3.83 0.76 0.56 
iv) Tert- butanol 4.15 0.82 0.61 
v) n- butanol 4.56 0.90 0.67 
vi) MTBE 5.04 1.00 0.74 
vii) Sec- Butanol 5.36 1.06 0.79 
viii) DIPE 5.76 1.14 0.85 
ix) Isobutanol 6.00 1.18 0.88 
x) ETBE 6.20 1.23 0.91 
xi) Tert- pentanol 6.43 1.28 0.95 
xii) DME 6.80 1.35 1.00 
xiii) n- Butanol 7.04 1.40 1.04 
xiv) Benzene 7.41 1.47 1.09 
xv) TAME 8.17 1.62 1.20 
 
Whenever possible, use stocks of at least 99.9 % purity. To minimize ev aporation of light components, chill all 
chemicals and gasoline used to prepare standards. Prepare standards by transfe rring a fixed volume of 
oxygenates using pipettes or eye droppers (for volumes below one volume percent) to 100 mL volumetric 
flasks or septum capped vials as follows. Cap and record th e tare weight of the volumetric flask or vial to 0.1 
mg. Remove the cap and carefully add the oxygenate to the flask or vial. Do not contaminate with sample the 
part within the flask or vial which contacts the cap. Cap and record the net mass (M i) to 0.1 mg of the 
oxygenate added. Repeat the addition and weighing procedur e for each oxygenates of interest. Similarly, add 
5 mL of the internal standard (DME) and record the net mass (M s) to 0.1 mg. Dilute each standard to 100.0 
mL with oxygenate-free gasoline or a mixture of hydroc arbons such as isooctane/mixed xylene (66.35 volume 
percent). Do not exceed 30 volume percent for all o xygenates, including the internal standard added. Store 
the capped calibrations standards below 5 °C when not in use . 
C.11.3 Standardization 
The area under each peak in the chromatogram is co nsidered a quantitative meas ure of the corresponding 
compound. Measure the peak area of each oxygenate and of the internal standard by either manual methods 
or electronic integrator. Calculate the relative volume  response factor of each oxygenate, relative to the 
internal standard. 
C.12 Procedure 
C.12.1 Preparation of sample 
Transfer 0.5 mL of internal standard (M s) by a volumetric pipette into a tared and capped 10 mL, volumetric 
flask. Record weight to nearest 0.1 mg. Record the net mass of the internal standard. Retare the capped flask. 
Fill the 10 mL volumetric flask to volume with sample, cap and record the net mass (Mg) to the nearest 0.1 mg 
of the sample added. Mix thoroughly and inject into the gas chromatography. If using an automatic sample  
28 © UNBS 2011 – All rights reserved
 then transfer an aliquot of the solution into a glass gas  chromatographic (GC) vial. Seal the GC vial with 
Teflon-lined septum. If the sample is not immediately analyzed, store below 5 °C. 
C.12.2 Chromatographic analysis 
Introduce a representative aliquot of the sample, co ntaining internal standard in to the chromatograph using 
the same technique as used for the calibration analysis. An  injection volume of 3 L with a 15:1 split ratio has 
been used successfully .  
C.12.3 Interpretation of chromatogram  
Compare the results of sample analysis to those of  calibration analysis to determine identification of 
oxygenates present. 
C.13 Calculation 
C.13.1 Mass concentration of oxygenates 
After identifying the various oxygenates, measure the ar ea of each oxygenate peak and that of the internal 
standard. From the least-squares fit calibrations, as depicted in the MTBE example in Figure 4, calculate the 
mass of each oxygenate (Mi) in the gasoline samples using response ratio (rsp i) of the areas of the oxygenate 
to that of the internal standard as follows: 
rsp i = (mi) (amt i) + b i 
where 
mi slope of the linear fit, 
bi y- intercept, and 
amt i amount ratio ( Mi/Ms). 
or 
amt i = (Mi)/Ms  = (rsp i - bi)/mi 
or 
Mi = [(rsp i-bi)/mi]Ms = [(Ai/As - bi)]Ms 
where 
Mi mass of oxygenate, and 
Ms mass of internal standard 
Ai-  Area of oxygenate peak 
As Area of internal standard peak 
To obtain mass percent (wi;) results for each oxygenate: 
   w i =Mi (100 percent)  
     M g FDUS 933: 2011 
© UNBS 2011 – All rights reserved  29
 
 
 
C.13.2 Report 
Report the mass content of each oxygenate to the nearest 0.01 mass percent.  
C.14 Precision and bias 
The precision of this test method as determined by the statistical examination of the inter-laboratory test 
results is as follows. 
The difference between successive results obtained by  the same operator with the same apparatus under 
constant operating conditions on identical test materi als would, in the long run, in the normal and correct 
operation of the test method exceed the follo wing values only in one case in twenty (see Table 5). 
RepeatabiIity Estimates for Oxygenates in Gasoline 
Component     Repeatability 
Methanol     0.09 (X 0.59) 
Ethanol      0.06 (X 0.61) 
Isopropanol     0.04 (X 0.56) 
Tert- Butanol     0.04 (X 0. 56) 
n- Propanol     0.003 (X 0.57) 
MTBE      0.05 (X 0.56) 
sec- Butanol     0.003 (X 0.61) 
DIPE      0.08 (X 0.56)  
30 © UNBS 2011 – All rights reserved
 Isobutanol     0.08 (X 0.56) 
ETBE      0.05 (X 0.82) 
Tert- Pentanol    0.04 (X 0.61) 
n- Butanol     0.06 (X 0.61) TAME      0.05 (X.0.70) 
Total oxygen     0.02 (X 1.26) 
where 
X is the mean mass percent of the component. 
The difference between two single and independent results obtained by different operators working in different 
laboratories on identical material would in the long run, exceed the following values only in one case in twenty (see Table 5). 
Table 5 — Precision Intervals - Determination from Cooperative Study Data  
 
 
 
 FDUS 933: 2011 
© UNBS 2011 – All rights reserved  31
 Reproducibility Estimates for Oxygenates in Gasoline 
Component     Repeatability 
Methanol     0.37 (X 0.59) 
Ethanol      0.23 (X 0.57) Isopropanol     0.42 (X 0.67) 
Tert- Butanol     0.19 (X 0. 67) 
n- Propanol     0.11 (X 0.57) 
MTBE      0.44 (X 0.67) 
sec- Butanol     0.42(X 0.67) 
DIPE      0.42 (X 0.67) Isobutanol     0.42 (X 0.67) 
ETBE      0.36 (X 0.76) 
Tert- Pentanol    0.15 (X 0.57) n- Butanol     0.22 (X 0.57) 
TAME      0.31 (X.0.51) 
Total oxygen     0.09 (X 1.27) 
where 
X is the mean mass percent of the component.  
32 © UNBS 2011 – All rights reserved
 Annex D  
(normative) 
 
Additional calculations 
D.1 Oxygenates content by volume 
For each component, calculate the oxygenate content in the sample, C 1 as a percentage by volume according 
to the following equation: 
C1 = 
21 0
PP C 
where 
Co content of the component calculated according to C.13.1 (percent); 
P1 density, in grams per millilitr e, of the gasoline sample,  and 
P2  density, in grams per millilitre, of the component  as given in Table 6. 
D.2 Total oxygen content 
D.2.1  For each component calculate the oxygen content in the sample C2, as a percentage by mass 
according to the following equation: 
MCC160
2×=  
where 
C0 content of the component calculated according to C.13.1 (percent); and 
M relative molecular mass of the component as given in Table 7. 
D.2.2  Calculate the total oxygen content of oxygenates  in the gasoline sample by summing the individual 
oxygen content C 2 (see D.2.1) for all components present. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  33
 Table 6 — Physical data for oxygenates 
SI No Component Relative molecular mass Density,  
g/mL at 20 °C 
(1) (2) (3) (4) 
A Alcohols 
i) Methanol 32 0.791 
ii) Ethanol 46 0.793 
iii) Propan-2-ol 60 0786 
iv) Butan-1-ol 74 0.810 
v) t- butyl alcohol 74 0.789 
Vi) Isobutyl alcohol 74 0.802 
B Ethers 
i) Methyl tertiary butyl ether 88 0.740 
ii) Ethyl tertiary butyl ether 102 0752 
iii) Methyl tertiary amyl ether 102 0.770 
  
34 © UNBS 2011 – All rights reserved
 Annex E 
(normative) 
 
Method for determination of ethanol content in 5 % ethanol doped motor 
gasoline by water extraction 
E.1 General 
This method covers the determination of ethanol cont ent in ethanol doped motor gasoline as field test at 
supply point, retail outlet etc. by using water. This me thod provides a test of on line ethanol doped gasoline for 
ethanol content by percent by volume. The method can suitably be used for estimation of ethanol content in 
ethanol doped motor gasoline and quantification 5 % ethanol (up to 8 %) can be made by using the method in 
down stream. In case of dispute the sample may be subjected to ASTM D 4815 method. 
E.2 Outline of the test method 
30 mL of water is added to 100 mL of ethanol doped  motor gasoline taken in 100 mL graduated stoppered 
cylinder. The mixture is shaken vigorously for about 30 s and cylinder is set aside for 5 min to observe the 
separation of aqueous layer. Increase in the volume of aqueous layer over and above 30 mL indicates the 
presence of extractable ethanol in the ethanol doped motor gasoline sample tested. The exact quantity of 
ethanol is then worked out referring the observation to the calibration plot. The plot is made on exact quantity 
of ethanol extracted from 100 mL of various known concentrations of ethanol doped motor gasoline using 30 
mL of water vis-a-vis the concentration of ethanol used fo r doping. For better results, the calibration chart shall 
be re-plotted whenever there is change in the source of motor gasoline. 
E.3 Significance and use 
The test method is employed to check the percentage of  ethanol in ethanol doped motor gasoline, as ethanol 
is having more affinity for mixing with water. The addition of water in ethanol doped motor gasoline extracts the ethanol present in the ethanol doped motor gasoline in to aqueous phase. The increase in the water level indicates the quantity of extractable ethanol in ethanol doped motor gasoline
. 
E.4 Chemical requirements 
E.4.1 Ethanol/denatured ethanol 
Is the pure chemical, otherwis e known as hydroxy-ethane, corr esponding to the constitution CH 3CH 20H and 
molecular formula, C 2H5OH. Nominally anhydrous ethanol (see  US 916) made unfit for beverage use by the 
addition of noxious or toxic materials (denaturants) and the same is used as ethanol for the purpose of doping motor gasoline. 
E.4.2 Motor gasoline  
A volatile mixture of liquid hydrocarbon, generally containi ng a small amount of additives, suitable for use as a 
fuel in spark ignition and internal combustion engines conforming to Table 1. 
E.4.3 Ethanol doped motor gasoline 
A fuel consisting primarily of motor gasoline doped with 5 percent (v/v) of denatured anhydrous ethanol for fuel. FDUS 933: 2011 
© UNBS 2011 – All rights reserved  35
 E.4.4 Water  
Distilled is preferred for extraction proce dure, but potable water may also be used. 
E.5 Apparatus 
E.5.1  100 mL glass stoppered cylinder  with 1 mL graduation. The distance between 100 mL mark and the 
top of the shoulder of the cylinder shall be above 40 mL. 
E.5.2  Graduated pipette , 1 mL to 10 mL. 
E.6 Calibration on known ethanol content in ethanol doped motor gasoline and its 
extraction 
E.6.1  Prepare a set of standards of ethanol doped moto r gasoline samples with the concentration of ethanol 
in motor gasoline ranging from 0.5 mL to 8 mL by percentage volume. Take 100 mL of each sample above in 
100 mL graduated stoppered clean and dry glass cylinder along with one blank motor gasoline (without 
ethanol). Add precisely 30 mL water to the sample. Shake the stopper cylinder vigorously for at least for 30 s. 
Loosen the stopper of glass cylinder to release the v apour pressure in the cylinder but do not remove the 
stopper. Tighten the stopper and allow the stopper cyli nder to sit undisturbed at ambient temperature upright 
on the leveled surface for a period of at least 5 min to allow the water-ethanol mixture to settle to the bottom. 
E.6.2  If separation of two layers is not complete, lightly tap the cylinder to encourage the complete 
separation. Record the level of aqueous layer in glass cylinder by reading the measur ement at the lowest part 
of the meniscus. 
Presence of ethanol percent in ethanol doped motor gasoline =  volume of aqueous layer observed in 
graduated cylinder – 30 mL (water added during testing) 
E.6.3  Plot a graph on various values obtained above as ordinate (X-axis) against corresponding 
concentration of ethanol used in the standard blend as abscissa (Y-axis) including that of the observation 
made on the blank. 
E.7 Procedure 
E.7.1 Take 100 mL sample of ethanol-blended motor gasoline under test in 100 ml graduated stoppered 
clean and dry glass cylinder, Add precisely 30 ml water to  the sample taken in the glass cylinder and place the 
stopper tightly. Shake the stoppered cylinder vigorously for at least 30 s. Loosen the stopper of glass cylinder 
to release the vapour pressure in the cylinder but do not remove the stopper. Tighten the stopper and allow 
the stoppered cylinder to sit undisturbed at ambient tem perature upright on the leveled surface for a period of 
at least 5 min to allow the water-ethanol mixture to settle to the bottom. E.7.2  If separation of two layers is not complete, lightly tap the cylinder to encourage the complete 
separation. Record the level of aqueous layer in glass cylinder by reading the measur ement at the lowest part 
of the meniscus. Presence of ethanol percent, in ethanol doped 
Presence of ethanol percent in ethanol doped motor gasoline =  volume of aqueous layer observed in 
graduated cylinder -30 mL (water added during testing) 
E.8 Calculation 
Observation made under E.7.2, is read against the standard plot in E.6.3 and the corresponding concentration 
of ethanol value is obtained. Whenever there is a change in  source of motor gasoline, for better results, it is 
recommended to re-plot the graph as mentioned in E.6.3.  
36 © UNBS 2011 – All rights reserved
 E.9 Report 
Report the corrected results obtained as per E.8 to the nearest 0.5 mL. 
E.10  Precision and bias 
E.10.1  In the absence of calibration plot the value observed in aqueous phase can be calculated to the 
nearest percentage volume as per th e under mentioned precision levels . 
E.10.2  Based on the field test data, it was observed that  a maximum of 4.6 mL (average) of ethanol content 
is extracted in to the aqueous phase as against 5 mL ethanol added in ethanol doped motor gasoline. 
E.10.3 The standard deviation of the test results indicates ± 0.24 % . 
E.10.4  Considering the precision of the graduated glass cylinder, the maximum possible measurement can 
be treated as 4.5 % volume with standard deviation of ± 0.5 %. Thus the repeatability under the method is as 
under: 
Percentage     Repeatability / Reproducibility 5 % 
(v/v)      0.5 mL (Approximately) 
. FDUS
© UNBS 2011 – All rights reserved  37
  933: 2011 
Certification marking 
Products that conform to Uganda standards may be  marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is gove rned by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licens ed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in co njunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and  testing in accordance with the 
certification mark scheme of the Uganda National  Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of  licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 FDUS 933: 2011
 
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