Proficiency testing schemes in Europe have shown that there was a need to improve the quality of the measurements to assess exposure to harmful chemicals in air at the workplace. Efforts were required to provide calibrants and CRMs for quality control.
Isocyanates are used in chemical synthesis, mainly in the production of polyurethane. They are potent allergogens. The determination of these reactive compounds is most often done by derivatisation using 1-(2-methoxyphenyl)-piperazine (2-MP) followed by HPLC.
The project aimed at the preparation and certification of three types of reference material:
(a) a powder simulating the residue obtained after evaporating the solvent of a solution used to sample workplace air for the determination of 2,4- as well as 2,6-toluene-diisocyanate (TDI), 4,4'-diphenyl methane diisocyanate (MDI) and hexamethylene diisocyanate (HDI);
(b) the same without isocyanates (reagents blank);
(c) pure solid 1-(2-methoxyphenyl)-piperazine derivatives of the listed diisocyanates (2,4-TDI-2-MP, 2,6-TDI-2MP, MDI-2-MP and HDI-2-MP).
Six reference materials have been prepared and certified:
CRM 556 2-MP DERIVATIVE OF 2,4-TOLUENE DIISOCYANATE (2,4-TDI)
CRM 557 2-MP DERIVATIVE OF 2,6-TOLUENE DIISOCYANATE (2,6-TDI)
CRM 558 2-MP DERIVATIVE OF 4,4'DIPHENYLMETHANE DIISOCYANATE (MDI)
CRM 559 2-MP) DERIVATIVE OF HEXAMETHYLENE DIISOCYANATE (HDI)
CRM 560 EVAPORATION RESIDUE OF A SOLUTION OF 2-MP IN ACETONITRILE
CRM 561 EVAPORATION RESIDUES OF A SOLUTION OF FOUR DIISOCYANATES AND AN EXCESS (2-MP) IN ACETONITRILE
and are available from IRMM.
The work done under this contract consisted of:
the preparation and the homogeneity and stability testing of the candidate reference materials
the coordination of the analytical campaign for the certification of these materials.