Reactive and Acid Dye Extractability Testing
topic
Extractable dye testing quantifies unfixed residual reactive, acid, and direct dye content released from poorly washed or over-dyed textiles into artificial acid perspiration, measuring dye concentration by spectrophotometry or HPLC at wavelengths corresponding to peak dye absorption, identifying batches where insufficient washing has left extractable dye above safe thresholds.
Role
Detects inadequate dyeing fixation and washing processes that leave extractable unfixed dye capable of migrating onto skin during perspiration, a particular risk with reactive dyes on cotton where hydrolysed unfixed dye not removed by washing can cause contact dermatitis in sensitised individuals.