Rubber Consultants has been granted ISO17025 accreditation via UKAS for testing to BSISO21461:2006, Rubber - Determination of the aromaticity of oil in vulcanised rubber compounds. GCMS methods also available for PAH or PNA analysis.

High aromatic oils are due to be banned in tyres next year in accordance with EU Directive 2005/69/EC, 16th November 2005.

From 1st January 2010 rubber products are not allowed to contain these aromatic oils which contain polyaromatic hydrocarbons (PAHs) and polynuclear aromatics (PNAs). Some of these materials are classified as carcinogens, others are suspected of being carcinogenic, especially benzo(a)pyrene.

BSISO21461:2006 is an NMR method which measures polyaromaticity in a purified dry residue extracted from the rubber. The molecular structure of certain non-linear PAHs with 3 or more fused rings contains a characteristic 3-sided concave area at the periphery of the molecule. The hydrogen atoms in this area are called bay region hydrogens. The level of these ‘bay protons’ is used as an indication of aromaticity.

A GCMS method is also available to analyse for individual PNAs, PAHs Polyaromatic hydrocarbons (PAHs)

In a product Rubber Consultants can also test for PAHs or PNAs which may originate from carbon black via their oil feedstock, or from aromatic oil extenders. This test can vary from a simple ‘quick look’ for pyrenes to a full scale fully quantitative analysis of PAHs or PNAs.

For tyres the limits are as follows:

<1mg/kg Benzo(a)pyrene
<10mg/kg in total of all the following PAHs

Benzo(a)pyrene
Benzo(e)pyrene
Benzo(a)anthracene
Chrysene
Benzo(b)fluoranthene
Benzo(j)fluoranthene
Benzo(k)fluoranthene
Dibenzo(a,h)anthracene

Rubbers can also be analysed to the German 2008 specification: no more than 1 mg/kg benzo(a)pyrene in the latex material and that the sum of all 18 PAHs is less than 10 mg/kg.

1.   acenaphthene                                CAS-No.    83-32-9
2.   acenaphthylene                              CAS-No.  208-96-8
3.   anthracene                                    CAS-No.  120-12-7
4.   benzo(a)pyrene                             CAS-No.    50-32-8
5.   benzo(e)pyrene                             CAS-No.  192-97-2
6.   benzo(a)anthracene                       CAS-No.    56-55-3
7.   benzo(a)phenanthrene (chrysene)    CAS-No.  218-01-9
8.   benzo(b)fluoranthene                     CAS-No.  205-99-2
9.   benzo(j)fluoranthene                      CAS-No.  205-82-3
10. benzo(k)fluoranthene                     CAS-No.  207-08-9
11. benzo(ghi)perylene                        CAS-No.  191-24-2
12. dibenz(a,h)anthracene                    CAS-No.    53-70-3
13. fluoranthene                                  CAS-No.  206-44-0
14. fluorene                                        CAS-No.    86-73-7
15. indeno(1,2,3-cd)pyrene                   CAS-No.  193-39-5
16. naphthalene                                  CAS-No.    91-20-3
17. phenanthrene                                CAS-No.    85-01-8
18. pyrene                                          CAS-No.  129-00-0

We also offer analysis for the EPA method 610 suite of PAHs (as above but without benzo(e)pyrene and benzo(j)fluoranthene).

A minimum of 10g of sample is requested for each test.

For more information please contact Sue Stephens or Colin Hull.