HPLC analysis of alkyl thioureas in an orthopaedic brace and patch testing with pure ethylbutylthiourea

Ethylbutylthiourea (EBTU) is an accelerator used in the production of chloroprene (neoprene) rubber. EBTU occurs in a mixture with diethylthiourea (DETU) and dibutylthiourea (DBTU) in the accelerator. An analytical method originally developed for analysis of zinc dithiocarbamates in rubber has been used to analyse EBTU, DETU and DBTU in a knee brace responsible for an allergic contact dermatitis in a gardener suffering from arthrosis. EBTU was isolated and gave positive reactions when tested as a pure compound. The test reaction was accompanied by positive reactions to DETU and DBTU.