Hydrogen Peroxide Residue Evaluation

The residual hydrogen peroxide sterilant remaining post sterilization was evaluated after exposure of the pouched 3DTA without any additional load to three Specialty Cycles. The test articles were extracted at 37 °C in sterile water for 24 to 72 h and analyzed for hydrogen peroxide residue by a validated (in accordance with USP < 1225>) xylenol orange spectrophotometric assay. The basis of the assay is the complexing of ferric ion (Fe 2+) by H₂0₂ in the presence of xylenol orange (CAS Number 3618-43-7). Peroxides in the sample oxidize Fe 2 + to Fe 3+, and the Fe 3 + forms a colored complex with xylenol orange that is read at 525 nm.