BS EN 14362-1-2012 禁用偶氮染料释放芳香胺欧盟测试方法(5)

Subsequently, 3,0 ml aqueous sodium dithionite solution (6.7), for reductive cleavage of the azo groups, are added to the reaction vessel, which is then shaken vigorously and immediately kept again at (70 ± 2) °C for another (30 ± 1) min whereupon it is cooled to room temperature (20 °C to 25 °C) within 2 min.

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禁用偶氮染料释放芳香胺欧盟测试方法,替代原-1&-2方法。

BS EN 14362-1:2012

EN 14362-1:2012 (E)

9.4 Separation and concentration of the amines

Add, to the reaction solution, 0,2 ml of the NaOH solution (6.11) and shake vigorously. Transfer the reaction solution to the diatomaceous earth column (7.5) and allow to be absorbed by the column for 15 min.

Meanwhile add 10 ml t-butyl methyl ether in the reaction vessel, shake vigorously and after the 15 min period the t-butylmethyl ether is decanted with the fibres onto the top of the column and the eluate is collected in a 100 ml round-bottom flask with standard ground joint or in a glass vessel for an evaporation apparatus (7.6). The reaction vessel is rinsed with 10 ml t-butylmethyl ether and the solvent is transferred to the column. Subsequently, 60 ml t-butyl methyl ether is poured directly on the column.

For amine detection and quantification, the t-butyl methyl ether extract is concentrated to about 1 ml (not to dryness!) at not more than 50 °C. If necessary, to exchange to another solvent, remove the remainder of the solvent very carefully by means of a weak flow of inert gas.

NOTE 1 Removal of the solvent (concentration in the rotary vacuum evaporator, evaporation to dryness) may lead to substantial amine losses if performed under uncontrolled conditions.

The extract or residue are immediately taken up to 2,0 ml of an appropriate solvent, e.g. acetonitrile or t-butyl methyl ether, and analysed without delay. If the complete analysis cannot be performed within 24 h, keep the extract below -18 °C.

NOTE 2 Owing to the matrix, individual amines, such as 2,4-diaminotoluene and 2,4-diaminoanisole are likely to exhibit a very poor stability. Where delays occur in the work routine, amines may be no longer detectable by the time of instrumental measurement.

9.5 Amine detection and quantification

Amine detection can be performed using the chromatographic techniques listed (7.8). Other validated methods may be used. If any amine is detected by one chromatographic method, then confirmation shall be made using one or more alternative methods. The result is positive only if both methods give a positive result. If any of the amines listed in Table 1 is identified, then at least a three point calibration curve is built up to quantify amine content.

NOTE

If the identified amines have isomers, care should be taken about the correct identification.

9.6 Check procedure

9.6.1 General

To check the procedure, 100 µl of the amine stock solution (6.10.1) (or a volume to give 30 µg of each amine in the reaction vessel) and 2,0 ml methanol are added to a reaction vessel (7.3) containing 15 ml of the preheated citrate/sodium hydroxide buffer solution (6.6). This check procedure shall be carried out with each batch of samples.

Then the procedure set out in 9.4 and 9.5 is carried out. Quantify this check standard based on the daily calibration (6.10.2).

9.6.2 Calibration using internal standard (quantification performed by gas chromatography)

ρS=ρc ×

where

As×AISC Vs

×

A c ×AISSV

ρs

concentration of the amine in the sample solution in µg/ml;

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禁用偶氮染料释放芳香胺欧盟测试方法,替代原-1&-2方法。

BS EN 14362-1:2012

EN 14362-1:2012 (E)

As Ac Aiss Aisc V

peak area of the amine in the specimen solution in area units; peak area of the amine in the calibration solution in area units;

peak area of the internal standard in the specimen solution in area units; peak area of the internal standard in the calibration solution in area units; final specimen volume made up to according to 9.4 in ml; amine solution volume used for check procedure, in ml; concentration of the amine in the calibration solution in µg/ml.

Vs

ρc

9.6.3 Calibration without internal standard

ρS=ρc ×

where

AsVs

× A c V

ρs

As Ac V

concentration of the amine in the sample solution in µg/ml; peak area of the amine in the specimen solution in area units; peak area of the amine in the calibration solution in area units; final specimen volume made up to according to 9.4 in ml; amine solution volume used for check procedure, in ml; concentration of the amine in the calibration solution in µg/ml.

Vs

ρc

Amine recovery rates shall comply with the following minimum requirements:

amines No. 1 to 4, 7, 9 to 17 and 20 to 21: 70 %; amine No. 8: 20 %; amines No. 18 and 19: 50 %; amines No. 5, 6 and 22, see footnotes to Table 1

aniline: 70 %

NOTE

Currently, there is insufficient experience to give minimum requirements for the amines not listed above.

10 Evaluation

10.1 General

If any amine is detected and/or quantified using daily calibration (6.10.2) above 5 mg/kg, the quantification shall be done using a multipoint calibration graph (6.10.3).

Plot a calibration graph of the response against the known standard concentration (corrected for the response for the internal standard if used). From the calibration graph, interpolate the concentration of the amine in µg/ml (ρs).

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禁用偶氮染料释放芳香胺欧盟测试方法,替代原-1&-2方法。

BS EN 14362-1:2012

EN 14362-1:2012 (E)

10.2 Calculation of amine in the sample

The amine level is calculated as mass portion w in mg/kg of the specimen according to the followin …… 此处隐藏：3601字，全部文档内容请下载后查看。喜欢就下载吧 ……