Background:
To make a correct diagnosis of allergic contact dermatitis, patch testing needs to be performed, and the patch test substances need to be pure.
Objective:
We wanted to study how pure commercial (meth)acrylic patch test substances are.
Methods:
The purity of (meth)acrylic patch test substances (diacrylates, dimethacrylates, and triacrylates) dissolved in acetone was determined by gas chromatography. The impurities were identified by mass spectrometry in both electron impact and chemical ionization mode.
Results:
The analyzed dimethacrylates were very pure (97% to 99%). The purity of the three studied diacrylates were 81% to 91%, but tripropyleneglycol diacrylate (81% pure) contained as much as 13% of tripropyleneglycol monoacrylate. The purities of the triacrylates were 82% to 86%. All diacrylates and triacrylates contained 1% to 13% of the corresponding hydroxyacrylates.
Conclusion:
The impurities may result in false interpretation of the patch test results, and accordingly in wrong diagnosis. If the patch test substance is impure, at least, the chemical impurities that can be detected by gas chromatography should be measured and reported in a certificate of analysis, preferably from each batch.
