Determination of peroxygen species present in pulp fiber matrixes

A new chromatographic method for the determination of oxidants, such as per oxyborates and peroxides, present in a pulp matrix has been developed. The new method is characterized by its high reproducibility, its low limit of d etection, and its high selectivity. Thioanisole (methylphenyl sulfide) is s hown to selectively and quantitatively react with oxidants that are present within a pulp matrix. The experimental protocol proposed requires an HPLC system with a normal-phase column. The method allows for the quantitative m onitoring of the thioanisole starting material, as well as the products of oxidation, methylphenyl sulfoxide and methylphenyl sulfone. After a 2-day r eaction period, the analysis time for a sample is less than 20 min. The det ection limit is 2.7 x 10(-6) M for the sulfoxide and sulfone and less than 5.0 x 10(-7) M for the thioanisole. This novel approach for monitoring oxid ants present on solid lignocellulosic matrixes may provide pulp and paper m anufacturers with a new tool for the study of the longterm bleaching effect iveness of peroxy-containing chemical additives.