Amines from azo dyestuffs

MAK amines, azo dyes according to LFGB

DIN EN ISO 14362-1 and DIN EN ISO 14362-3 define procedures to test for azo dyes that can release prohibited primary aromatic amines. In both procedures, the dyes are extracted and reduced and then the concentration of the amines is determined.

Test description

Dyeing textiles is a subject of its own and significantly more complex and difficult than it appears at first glance. The colours must be easy to use, they should be stable against light and other environmental influences and, of course, they must not wash out of the textile. And all this over a long period of use. This list of requirements is not easy to comply with. In particular, the type of dye used has a great influence on the properties. For a long time, so-called azo dyes were used. These are so called because they all have the chemical azo compound as a building block. This azo compound can be broken down, which does not happen in normal use but over a long time. Exposure to light or reductive stain remover slowly releases the resulting fragments. Many of these fragments consist of so-called primary aromatic amines, almost all of which are carcinogenic.

Legislators in the EU have restricted azo dyes for use in textiles through the REACH regulation, which is why a marketability test should include azo dyes. Because despite the ban, it is still possible that these dyes are used, either because regulation is not as thorough in other parts of the world or because a small amount of a banned dye has been used to refine the colour of the final textile.

The test is carried out according to DIN EN ISO 14362-1. The dyes and/or the amines are extracted and reduced in an aqueous citrate buffer. The amines are then dissolved in tert-butyl ether using an SPE column. The amount of solvent is reduced and the concentration of the amines is determined.

There are a few variables in this workup. The colours have to be extracted differently from different types of fibres. In addition, there are some amines that decompose further under the above conditions. To detect these, DIN EN ISO 14362-3 is used, which sets the pH differently during reduction and thus prevents further decomposition.

Options

  • MAK-Amine, analysis of dyes – a house variant of DIN EN ISO 14362-1, in which dyes are processed directly. In the case of dyes that are present in particles, the method may yield results that are too low.
  • Leather is carried out according to the standard DIN EN ISO 17234-1, but charged normally.

Required material for the test

  • minimum 3 g of fabric weight (per colour)

Additional Tips

We carry out all different refurbishments as required, whereby we charge all refurbishments and variants the same.

The test depends on the colour. If a product has many different colours, the number of samples increases.

How do we work

Our workflow

01

Specifications

At the beginning, we clarify the scope of testing, the goal of the tests and, if applicable, the project requirements with the customer.

02

Offer

We prepare a quotation based on the scope of testing and the requirements

03

Test

The order is clear and as soon as the test sample is received in the laboratory, we get straight to work with the sample.

04

Submitted test reports

The results are available in the form of a test report. In addition to the pure test result, an overall assessment according to legal, general or customer-specific requirements is possible.

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