Epoxy resins are important industrial polymers mainly used in protective coatings and in electrical applications. A majority of epoxies are based on diglycidyl ether of bisphenol A (DGEBA). The most widely used curing agent for epoxy coatings are different polyamines but carboxylic acids, anhydrides etc. have also been used. Epoxy compounds and amines may cause skin irritations and contact dermatitis. The allergic effect of DGEBA is decreasing with increasing molecular weight and the smallest DGEBA with a molecular weight of 370 is considered as the most potent.

We have tested a chromatographic method for determination of epoxies and polyamines without derivatisation. Dimethyl formamide (DMF) stops the curing reaction and allows the free epoxy groups to be preserved. With the use of LC-MS with electrospray ionisation in positive mode, a simultaneous qualitative determination of epoxies and polyamines was achieved. Separation of the analytes and DMF was performed with reversed phase chromatography on an ODS column. The spectras showed the protonated molecule and some diagnostic fragments for polyamines and the epoxy, respectively. This analytical procedure is to be used for product analysis and together with sampling methods for air concentration measurements and skin exposure determinations.

For the assessment of dermal exposure to DGEBA, field sampling was performed on persons working with application of seamless floors. The product used was a two-component system with 7% DGEBA. The sampling was performed either with patches attached to the skin during a work shift or as tape stripping after a work shift. For the method comparison the two methods were used side by side. For both methods Fixomull® (Beiersdorf AG, Germany), 3 x 3 cm was used. The Fixomull® is a self-adhesive gauze with woven polyester backing and a polyacrylate adhesive. The workers used ordinary leather gloves and sampling was performed on the right and left hand inside the glove and on the skin just above the glove. Sampling was performed on two persons during five work shifts. Method comparison measurements were performed during three of the work shifts.

The tapes were transferred to glass vials with 1 ml of DMF, extracted during ultrasonification and stored in freezer prior to analysis. A detection limit of about 0.045 µg DGEBA (Mv 370)/sample was achieved. No negative effects or increased blank values due to the tape could be seen.

DGEBA was detected in all sampling locations with both sampling methods. The amount found with the stripping method was about 60% of the amount found with the patch method with a variation from 2 to 400%. The mean concentration found with the patch method was 0.08 µg cm-2 h-1 with a maximum value of 0.41 µg cm-2 h-1. For the stripping method, a mean value of 0.03 µg cm-2 h-1 and a maximum value of 0.24 µg cm-2 h-1 were found. The use of leather gloves does not protect against DGEBA skin exposure.

These sampling methods are to be more thoroughly studied at the laboratory and during field sampling in different occupational environments. The measurements give information on current exposure levels but are also intended to be a basis for recommendations on sampling strategy in different workplaces.