1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58cyclic and linear oligomers by HPLCICS 83.080.01Plastics Determination of caprolactam and its BRITI
2、SH STANDARDBS ISO 15033:2007BS ISO 15033:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2007ISBN 978 0 580 53017 3Amendments issued since publicationAmd. No. Date Commentscontract. Users are responsible for its correct a
3、pplication.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 15033:2007. It supersedes BS ISO 15033:2000 which is withdrawn.The UK participation in its preparation was entru
4、sted to Technical Committee PRI/21, Testing of plastics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a Reference numberISO 15033:2007(E)INTERNATIONAL STANDARD ISO15033Sec
5、ond edition2007-03-15Plastics Determination of caprolactam and its cyclic and linear oligomers by HPLC Plastiques Dtermination du caprolactame et de ses oligomres cycliques et linaires par CLHP BS ISO 15033:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 T
6、erms and definitions. 1 4 Principle. 1 5 Reagents 1 6 Apparatus 3 7 Test sample . 4 8 Procedure 4 8.1 Calibration . 4 8.2 Determination 4 9 Calculations. 6 9.1 Calculation of calibration factors 6 9.2 Test sample . 7 10 Precision 7 11 Test report . 8 Annex A (normative) HPLC parameters and injector
7、programme 9 Annex B (informative) Schematic diagram of HPLC apparatus. 10 Bibliography . 11 BS ISO 15033:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards
8、is normally carried out through ISO technical 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 pa
9、rt in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to
10、prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility th
11、at some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 15033 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-chemical properties. This second edition cance
12、ls and replaces the first edition (ISO 15033:2000), which has been technically revised. BS ISO 15033:2007vIntroduction The basic method specified in this International Standard can be used for HPLC determination of the cyclic oligomers of caprolactam up to and including the hexamer (n = 6), using UV
13、 detection. If desired, after post-column reaction of the primary amine with 1,2-phthalic dicarboxaldehyde, on-line determination of the linear oligomers up to and including the hexamer can also be carried out. The determination is not quantitative for oligomers higher than the hexamer (n 6). In the
14、 determination of cyclic oligomers the sensitivity for the tetramer and higher oligomers is constant, which means that calibration should take place up to and including the tetramer (n = 4). The linear oligomers are determined by the fluorescence of the iso-indole group, which is a product of the re
15、action between the primary amino group, 1,2-phthalic dicarboxaldehyde and 3-mercaptopropionic acid. The calibration with the linear oligomers should be carried out up to and including the hexamer (n = 6). BS ISO 15033:2007blank1Plastics Determination of caprolactam and its cyclic and linear oligomer
16、s by HPLC SAFETY STATEMENT Persons using this document should be familiar with normal laboratory practice, if applicable. This document does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and he
17、alth practices and to ensure compliance with any regulatory requirements. 1 Scope This International Standard describes an HPLC (high-performance liquid chromatography) method for determining the concentrations of cyclic oligomers of caprolactam, from 0,01 % by mass upwards, and linear oligomers of
18、caprolactam, from 5 mg/kg upwards, both up to and including the hexamer of caprolactam (n = 6), in samples of polyamide 6, caprolactam and mixtures of rearrangement products in water. 2 Normative references The following referenced documents are indispensable for the application of this document. Fo
19、r dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 472, Plastics Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 472 apply. 4 Pr
20、inciple A test sample is dissolved in, or diluted with, formic acid and the oligomers separated in the presence of a low-pH mobile phase using a column filled with reversed-phase packing material. The cyclic oligomers are detected by UV absorption at 200 nm. If desired, the linear oligomers can be d
21、etected by fluorescence after post-column reaction of the primary amino group with 1,2-phthalic dicarboxaldehyde and 3-mercaptopropionic acid. The concentrations are calculated by comparison of the measured values with those of calibration solutions. 5 Reagents During the analysis, unless otherwise
22、stated, use only reagents of recognized analytical grade. 5.1 Water, ultrapure or double-distilled. 5.2 Phosphoric acid, 85 % by mass. BS ISO 15033:20072 5.3 Phosphoric acid, 1 mol/l. Introduce 68 ml of phosphoric acid (5.2) into a 1-litre volumetric flask, make up to the mark with water (5.1) and m
23、ix well. 5.4 Acetonitrile. 5.5 Formic acid, concentrated. 5.6 Caprolactam. 5.7 Cyclic dimer of caprolactam, isolated by HPLC (see Note). 5.8 Cyclic trimer of caprolactam, isolated by HPLC (see Note). 5.9 Mixture of cyclic oligomers of caprolactam, isolated by HPLC (see Note). 5.10 -Aminocaproic acid
24、. 5.11 Linear dimer of -aminocaproic acid. 5.12 Linear trimer of -aminocaproic acid. 5.13 Linear tetramer of -aminocaproic acid. 5.14 Linear pentamer of -aminocaproic acid. 5.15 Linear hexamer of -aminocaproic acid. 5.16 Helium. 5.17 Eluent. Add 10 ml of acetonitrile (5.4) and 10 ml of phosphoric ac
25、id (5.3) to 900 ml of water (5.1). Raise the pH of the solution to 2,6 using sodium hydroxide flakes (5.19). Make up to 1 litre and saturate with helium (5.16). 5.18 Sodium tetraborate decahydrate. 5.19 Sodium hydroxide flakes. 5.20 1,2-Phthalic dicarboxaldehyde. 5.21 Methanol, 96 % by volume. 5.22
26、3-Mercaptopropionic acid. 5.23 Post-column derivatization reagent. Dissolve 76 g of sodium tetraborate decahydrate (5.18) and 6 g of sodium hydroxide (5.19) in 2 litres of water (5.1). Dissolve 1,6 g of 1,2-phthalic dicarboxaldehyde (5.20) in 40 ml of methanol (5.21) and add this solution to the sod
27、ium tetraborate decahydrate reagent. Add 1,5 ml of 3-mercaptopropionic acid (5.22) and mix well. The stability of the post-column derivatization reagent is limited. Do not keep for longer than 3 days. NOTE The cyclic dimer, the cyclic trimer and the mixture of cyclic oligomers of caprolactam can be
28、isolated from a methanol extract of PA6 by preparative HPLC, using the HPLC method described here. The purity of the dimer and the possible presence of other oligomers can be checked using the method described in this International Standard. BS ISO 15033:200736 Apparatus 6.1 HPLC equipment, having t
29、he following specifications: Eluent pump, including mixer, damper and manometric module, giving an eluent flow rate of 0,51 ml/min and a pressure drop of approximately 100 bar. Injector, e.g. an auto-sampler capable of 1 l to 250 l injections, equipped to carry out a variable injector programme (see
30、 Annex A). The injector shall be capable of accommodating at least three components in the sample loop, i.e. the injector programme shall be capable of controlling the “sandwich” injection of up to three components into the sample loop plus a solvent injection in one HPLC run. Column: stainless stee
31、l inside diameter: 3 mm length: 250 mm temperature: 40 C packing: reversed-phase C18 silica or equivalent particle size: 0,005 mm The resolution of the column shall be such that baseline separation of the components of interest is obtained. The lifetime of the reversed-phase C18 column is very stron
32、gly influenced by the C18-silica bonding of the packing material. Therefore, columns equipped with a packing material containing monofunctional silanes with diisobutyl side-chain groups are preferred. These side groups sterically protect the key silanes from hydrolytic attack at low pH, making the s
33、tationary phase stable at such pH (pH 1). UV detector: wavelength 200 nm and 220 nm. And additionally for determination of the linear oligomers: Reagent pump, including manometric module and pulse damper, giving a reagent flow rate of 0,25 ml/min and a reagent pressure drop of approximately 20 bar.
34、Reaction coil: stainless steel or PEEK length: 3 m inside diameter: 0,25 mm temperature: 25 C Fluorescence detector: excitation: 330 nm emission: 420 nm A schematic diagram of an HPLC apparatus is given in Annex B. BS ISO 15033:20074 6.2 Microbalance, accurate to 0,1 mg. 6.3 Ultrasonic vibration bat
35、h. 6.4 Volumetric flask, capacity 25 ml. 7 Test sample For polyamide 6 and caprolactam, the maximum test sample size shall be 0,5 g. For mixtures of rearrangement products in water, a maximum test sample size of 1,25 g shall be used. The stability of the dissolved samples is limited, since caprolact
36、am is hydrolysed to -aminocapronic acid. Do not keep for longer than 6 days. 8 Procedure 8.1 Calibration To calibrate the column for the cyclic oligomers, prepare a series of three calibration solutions with concentrations increasing from 100 mg/l to 1 500 mg/l by dissolution in formic acid (5.5) fo
37、r caprolactam (5.6), the cyclic dimer (5.7), the cyclic trimer (5.8) and the oligomer mixture (5.9). To calibrate the column for the linear oligomers, prepare a series of three calibration solutions with concentrations increasing from 2 mg/l to 15 mg/l by dissolving in formic acid (5.5) for -aminoca
38、proic acid (5.10) and each of the linear oligomers from the dimer (5.11) to the hexamer (5.15). Pump eluent (5.17) through the column at a rate of 0,51 ml/min. Starting with the lowest concentration of a calibration series, inject 2 l of the calibration solution into the column in accordance with th
39、e injector programme given in Annex A. Elute in accordance with the gradient timetable in Annex A. Record the UV chromatogram. If applicable, immediately after UV detection, add the post-column reagent (5.23) at a rate of 0,25 ml/min, mixing the eluent and the reagent in the reaction coil. Record th
40、e fluorescence chromatogram. Measure the peak area of the component(s). Repeat the calibration successively for the other calibration solutions of the same component and for the other calibration series. NOTE Calibration can also be carried out using a commercially available PA6 polymer with a known
41、 concentration of cyclic and linear oligomers (see Reference 3 in the Bibliography). 8.2 Determination Introduce a test sample (see Clause 7) into a 25 ml volumetric flask. Add 20 ml of formic acid (5.5), close the flask and dissolve the sample, optionally by using ultrasonic vibration. Make up to t
42、he mark with formic acid (5.5). Pump eluent (5.17) through the column at a flow rate of 0,51 ml/min. Inject 2 l of the sample solution into the column in accordance with the injector programme given in Annex A. Elute in accordance with the gradient timetable in Annex A. Record the UV chromatogram (s
43、ee Figure 1). If applicable, immediately after UV detection, add the post-column reagent (5.23) at a flow rate of 0,25 ml/min, mixing the eluent and the reagent in the reaction coil. Record the fluorescence chromatogram (see Figure 2). Measure the peak areas of the cyclic oligomers (UV detection) an
44、d linear oligomers (fluorescence detection) up to and including the hexamer. NOTE If necessary, e.g. if lower sensitivity is necessary due to high(er) concentrations, caprolactam can be detected by UV absorption at 220 nm instead of 200 nm. BS ISO 15033:20075Key X retention time (min) Y response (mV
45、) 1 formic acid sandwich injection 2 250 l formic acid injection C1 to C6 cyclic oligomers L2 to L6 linear oligomers Figure 1 Determination of the cyclic oligomers of caprolactam Key X retention time (min) Y response (mV) L1 to L6 linear oligomers Figure 2 Determination of the linear oligomers of ca
46、prolactam BS ISO 15033:20076 9 Calculations 9.1 Calculation of calibration factors 9.1.1 Calibration factors for cyclic oligomers Calculate the calibration factor for the relevant component for each solution using the following equation (see Note 1): cccAfC= (1) where Acis the peak area of the relev
47、ant component; Ccis the concentration of the relevant component in the calibration solution, in mg/l; fcis the calibration factor for the relevant component. Calculate the calibration factors for n = 1 up to and including n = 3 by taking the mean value of the three calculated calibration factors in
48、the series of the relevant component. The calibration factors for the tetramer (n = 4) up to and including the hexamer (n = 6) are assumed to be constant. The calibration factor for the oligomers from n = 4 up to and including n = 6 is calculated from the chromatogram of the oligomer mixture, the ca
49、libration factors for n = 1 up to and including n = 3 being known. Calculate the calibration factor for n = 4 to n = 6 by taking the mean value of the three calculated calibration factors in the series. The calibration shall be repeated if the relative difference between the calibration factors for two solutions is more than 5 %. NOTE 1 The calibration factor for e.g. n = 3 can also be calculated by using for instance a calibration solution also containing caprolactam and/or the cy
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