[Determination of dihydroxybenzenes using high performance liquid chromatography with acidic potassium permanganate...

A sensitive, selective and simple post-column chemiluminescence (CL) detection method for simultaneously determining catechol, resorcinol, hydroquinone has been developed based on high performance liquid chromatography (HPLC) coupled with CL detection using reaction of dihydroxybenzenes with acidified potassium permanganate solution with the enhancing effect of formic acid. The optimal conditions for the CL detection and HPLC separation were achieved. Dihydroxybenzene isomers were baseline separated at column temperature of 25 degrees C using a mobile phase of methanol-0.1 mmol/L beta-cyclodextrin aqueous solution (30/70, v/v) with an isocratic elution program and the mobile phase matched well the CL detection. For all compounds, the linear ranges of the CL detection were about two orders of magnitude. The detection limits were 3.2 microg/L for hydroquinone, 4.7 microg/L for resorcinol and 5.2 microg/L for catechol. Combining with solid phase extraction, the proposed method was successfully applied to the determination of dihydroxybenzenes in river water. The recoveries for the three dihydroxybenzenes were 92.1%-95.4%.