The most interesting PCAs are 1,2,3,4-butanetetracarboxylic acid (BTCA) and citric acid (CA).
Since, to date, no analytical method is available to determine both qualitatively and quantitatively the amount of these cross-linking agents that have reacted with the cellulosic material, isocratic HPLC (stationary phase: Aminex HPX-87H, mobile phase (c½ H2SO4) = 0.01 mol/L) was applied to evaluate the non-formaldehyde finishing agent linked to the cellulose.