SENSITIVE DETERMINATION OF AIRBORNE DIISOCYANATES BY HPLC - 4,4'-DIPHENYLMETHANE-DIISOCYANATE (MDI)

An HPLC/fluorescence method is described, which enables the sensitive determination of airborne monomeric 4,4'-diphenyl-methane-diisocyanate (MDI). A glass fiber filter coated with 1 mg l-(2-pyridyl)-piperazine (2PP) is used for sampling. The urea derivative MDI-2PP, which shows a high molecular absorption coefficient and exhibits a sufficient fluo rescence response, is extracted from the filter by use of a 90:10 acet onitrile/DMSO mixture. Linear calibration curves were obtained for the indoor range (7.8 ng/mL to 74.7 ng/mL) and the workplace range (27.7 ng/mL to 676.0 ng/mL). A detection limit of 9.0 ng/m(3) can be achieve d on a total sampling volume of 1000 L. The method is easy to handle a nd therefore highly suitable for a routine determination of MDI in the atmosphere of workplace areas and living environments.