1、 ISO 2016 Petroleum products Biodiesel Determination of free and total glycerin and mono-, di- and tracylglycerols by gas chromatography Produits ptroliers Biogazole Dtermination de glycerine libre et totale et des mono-, di- et tracylglycerols avec chromatographie gazeuse TECHNICAL SPECIFICATION IS
2、O/TS 17306 Reference number ISO/TS 17306:2016(E) First edition 2016-02-01 ISO/TS 17306:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized oth
3、erwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright offic
4、e Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO/TS 17306:2016(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Principle 2 5 Apparatus . 2 6 Reagents and mate
5、rials . 3 7 Preparation of the apparatus 3 8 Sampling 4 9 Preparation of the standard solutions . 4 9.1 Preparation of the stock solutions . 4 9.2 Preparation of the calibration curve 5 9.3 Preparation of the sample . 6 9.4 Procedure 7 10 Calculation and expression of results . 8 11 Precision 10 11.
6、1 General 10 11.2 Repeatability, r .10 11.3 Reproducibility, R 10 12 Test report 11 Annex A (normative) Check chromatograms 12 Annex B (normative) Calculation of the c oefficients for det ermination of the c ombined glycerol 16 Annex C (informative) Information on interlaboratory study 20 Bibliograp
7、hy .21 ISO 2016 All rights reserved iii Contents Page ISO/TS 17306:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO t
8、echnical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates clos
9、ely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria
10、needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of pat
11、ent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name use
12、d in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Ba
13、rriers to Trade (TBT) see the following URL: Foreword - Supplementary information The committee responsible for this document is ISO/TC 28, Petroleum products and related products of synthetic or biological origin, Subcommittee SC 7, Liquid biofuels.iv ISO 2016 All rights reserved ISO/TS 17306:2016(
14、E) Introduction This Technical Specification establishes a method for quantitative determination of free glycerol, mono-, di-, triacylglycerols and total glycerol in fatty acid methyl esters (biodiesel) by gas chromatography. High concentrations of these components can contribute to formation of dep
15、osits on the pistons and valves of diesel cycle engines. Additionally, they can cause problems during storage and in the engines fuel injection system. Alternative methods for similar determinations exist in ASTM D6584 2and EN 14105, 3which are tailor made to regional quality specification needs. Th
16、is Technical Specification describes an alternative technique using more easily available internal standards, instrumentation that can also measure esters and a procedure applicable to short chain fatty acid esters, such as those from palm kernel and coconut oil. This Technical Specification thus pr
17、ovides a wider usage with similar or worse precision as other techniques. ISO 2016 All rights reserved v Petroleum products Biodiesel Determination of free and total glycerin and mono-, di- and tracylglycerols by gas chromatography W A R N I N G T h e u s e o f t h i s T e c h n i c a l S p e c i f
18、i c a t i o n m a y i n v o l v e t h e u s a g e o f d a n g e r o u s materials and equipment. It is the responsibility of the user to establish the appropriate security, health and environmental practices, and to determine the applicability of regulatory limitations before their use. 1 Scope This
19、 Technical Specification establishes a methodology for quantitative determination of free glycerol, mono-, di-, triacylglycerols and total glycerol by gas chromatography in biodiesel produced from any raw material including coconut or palm oil and animal fat. It is not applicable for biodiesel from
20、castor oil. In most actual cases, biodiesel is based on fatty acid methyl esters (FAME). These have also been used during the precision study for this test method. There is no indication that the methodology does not apply to other ester types, but the precision has not been determined nor compared.
21、 NOTE For the purposes of this Technical Specification, the term “% (m/m)” is used to represent the mass fraction, . 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only
22、the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3170, Petroleum liquids Manual sampling ISO 3171, Petroleum liquids Automatic pipeline sampling 3 T erms a nd definiti ons For the purposes of this document, the f
23、ollowing terms and definitions apply. 3.1 biodiesel fuel comprised of mono-alkyl esters of fatty acids, derived from vegetable oils or animal fats 3.2 bonded glycerol glycerol portion of the mono-, di-, and triacylglycerols molecules 3.3 total glycerol sum of free glycerol and bonded glycerol 3.4 mo
24、noacylglycerols sum of monostearin, monopalmitin, monoolein, monolinolein, concentrations and/or other monoacylglycerols present in the biodiesel TECHNICAL SPECIFICATION ISO/TS 17306:2016(E) ISO 2016 All rights reserved 1 ISO/TS 17306:2016(E) 3.5 diacylglycerols sum of diolein, dilinolein concentrat
25、ions and/or other diacylglycerols present in the biodiesel 3.6 triacylglycerols sum of triolein, trilinolein concentrations and/or other triacylglycerols present in the biodiesel 3.7 silylation reaction to substitute the active hydrogen present in the mono- and diacylglycerol molecules to obtain mor
26、e volatile and stable compounds 4 Principle A sample is injected into a gas chromatograph after silylation with N-methyl-N-trimethylsilyltrifluoro- acetamide (MSTFA). The identification of the components in the sample is done by comparing the retention times of four reference materials (glycerol, mo
27、noolein, diolein and triolein). The quantification is done using calibration curves with internal standardization. For quantifying the glycerin and the acylglycerols, ethylene glycol and tricaprin are used as internal standard, respectively. The total glycerol is obtained from the sum of free and bo
28、nded glycerol concentrations. 5 Apparatus 5.1 Gas chromatograph equipped with flame ionization detector (FID), an on-column (or equivalent) injector and oven with temperature programming. 5.2 Data acquisition system, an electronic instrument to obtain and record the peak area in the chromatograms. 5
29、.3 Column, fused silica capillary column, 30 m 0,32 mm 0,1 m, with stationary phase 95 % dimethylpolysiloxane and 5 % phenyl-methylpolysiloxane for high temperature (up to 400 C). NOTE 1 Any column with better or equivalent efficiency and selectivity can be used. Their usefulness can be observed by
30、comparing the chromatogram obtained with chromatograms presented in Annex A. NOTE 2 A retention gap of 0,53 mm of internal diameter can be used. 5.4 Automatic sampler. 5.5 Balance, with resolution of 0,1 mg. 5.6 V olumetric flasks of 50 ml, 25 ml and 10 ml 5.7 Appropriate vials for automatic sampler
31、, screw top vials can lead to sample evaporation. 5.8 Flask, with a capacity of 10 ml, with polytetrafluoroethylene (PTFE) faced septa. 5.9 Microlitre syringes, with a capacity of 5 l for sample injection. 5.10 Microlitre syringes or micropipette, with a capacity of 100 l and 250 l for the preparati
32、on of the solutions. 5.11 Pasteur pipettes.2 ISO 2016 All rights reserved ISO/TS 17306:2016(E) 5.12 Volumetric pipettes, graduated, with a capacity of 10 ml and 20 ml. 6 Reagents and materials 6.1 n-heptane, 99,0 % minimum purity. 6.2 Pyridine (dried), 99,0 % minimum purity, with a maximum water con
33、tent of 0,1 %. It is recommended that the pyridine be stored with a molecular sieve 5A, 4/8 mesh. Its conditioning should be undertaken in a lab oven, at 350 C throughout the night. Allow cooling down in a desiccant, without silica. 6.3 1-Glycerolmonooctadecenoate (glycerol monooleate or monoolein)
34、(CAS 1)No. 111-03-5), 99,0 % minimum purity. 6.4 1,3 Glycerol dioctadecenoate (glycerol dioleate or diolein) (CAS No. 2465-32-9), 99,0 % minimum purity. 6.5 Glycerol trioctadecenoate (glycerol trioleate or triolein) (CAS No. 122-32-7), 99,0 % minimum purity. 6.6 Glycerol (CAS N 56-81-5), 99,5 % mini
35、mum purity. 6.7 Ethylene glycol (CAS No. 107-21-1), 99,0 % minimum purity. 6.8 Tricaprin (CAS N 621-71-6), 99,0 % minimum purity. 6.9 N-meth y l-N-trimeth y lsil y ltrifluor oac etamide ( MS TF A), reagent grade. IMPORTANT For silylation purposes, interaction with water shall be prevented. 6.10 Carr
36、ier gas, hydrogen or helium, 99,999 % minimum purity, as carrier gas (for detector gas a FID suitable grade is allowed). 6.11 Nitrogen, grade suitable for FID. 6.12 Synthetic air, grade suitable for FID. 7 Preparation of the apparatus 7.1 Install the column according to the instructions of the manuf
37、acturer. 7.2 Establish a carrier gas flow of around 3,0 ml/min in the column (pressure of 180 kPa and average linear velocity of around 0,54 m/s if helium is used or 105 kPa and 0,70 m/s to hydrogen). 7.3 Adjust the following typical operating conditions on the gas chromatograph: 1) Represents the r
38、egister of chemical substances catalogued in the CAS system. CAS numbers have no chemical meaning, these are numbers designated in sequential order for each substance added to the system. ISO 2016 All rights reserved 3 ISO/TS 17306:2016(E) a) oven temperature programming: Oven program rate C/min Tem
39、perature C Holding time min 50 1 15 180 0 7 230 0 20 380 10 b) carrier gas: helium or hydrogen; c) detector temperature: 380 C; d) injector temperature: oven tracking; e) nitrogen flow (make-up gas): 30 ml/min; f) hydrogen flow to the detector: 35 ml/min; g) synthetic air flow to the detector: 350 m
40、l/min; NOTE The detector flows recommended by the manufacturer can also be used. h) volume injected: 1,0 l; i) run time: 35 min. 7.4 Evaluate the stability of the baseline running a blank. 7.5 After system stabilization, baseline subtraction or electronic compensation following the procedures descri
41、bed in the equipments manual can be applied to eliminate the deviation of the baseline due to the temperature programming of the oven. Care should be taken not to lose the raw data if required for good laboratory practices. 8 Sampling Unless otherwise specified, obtain representative samples for ana
42、lysis in accordance with the procedures given in ISO 3170, ISO 3171 or an equivalent National Standard. 9 Preparation of the standard solutions 9.1 Preparation of the stock solutions In a flask with adequate capacity, prepare stock solutions for each substance according to Table 1, recording the res
43、pective masses. Store and keep the solutions in the refrigerator when not in use. NOTE Under these conditions, the stock solutions can be stored for one month.4 ISO 2016 All rights reserved ISO/TS 17306:2016(E) Table 1 Preparation of the stock solutions Compound Approximate mass mg Pyridine mass G G
44、lycerin 25 49,0 Monoolein 50 9,80 Diolein 50 9,80 Triolein 50 9,80 Ethylene glycol (internal standard 1) 25 24,5 Tricaprin (internal standard 2) 80 9,80 Calculate the concentrations of the stock solutions using Formula (1): (1) whereC SS is the concentrations of the compounds in the stock solutions
45、in % (m/m);m SS is the mass of the compounds used in the preparation of the stock solutions, with a precision of 0,1 mg;m T is the total mass (m compound+ m pyridine ), with a precision of 0,1 mg. 9.2 Preparation of the calibration curve 9.2.1 In a flask with a capacity of 10 ml (5.8), prepare the s
46、tandard solution one by adding the stock solutions according to the indications on Table 2. Record the masses of each stock solution added. 9.2.2 Repeat the same procedure for the other standard solutions 2, 3, 4 and 5 from Table 2. 9.2.3 Add to each of the five standard solutions 100 l of MSTFA. Cl
47、ose the flask and shake vigorously. Let it react for at least 20 min at room temperature. 9.2.4 After the reaction time, add approximately 8 ml of n-heptane and shake, transfer a portion to an automatic sampler vial and seal. 9.2.5 Inject 1,0 l of each solution, at least twice. Identify the peaks ac
48、cording to their retention times; an elution order is presented in Figure A.1. Table 2 Preparation of the standard solutions Standard solution 1 2 3 4 5 Stock solution of glycerin (l) 10 30 50 70 100 Stock solution of monoolein (l) 20 50 100 150 200 Stock solution of diolein (l) 10 20 40 70 100 Stoc
49、k solution of triolein (l) 10 20 40 70 100 Stock solution of ethylene glycol (l) 100 100 100 100 100 Stock solution of tricaprin (l) 100 100 100 100 100 ISO 2016 All rights reserved 5 ISO/TS 17306:2016(E) 9.2.6 Use Formula (2) to calculate the mass of all the compounds present in the standard solutions which will be used in calibration curves. (2) wherem C is the mass of the compounds used in the preparation of the standard solutions, with a preci- sion of
