Acceleration of Complexation of Cr(III)-4-(2-pyridylazo)resorcinolato Complex by Microwave Heating and Its Application to Derivatization Reaction in Pre-column Derivatization-HPLC Determination of Trace Cr(III)

The acceleration of a complexation of Cr(III)-4-(2-pyridylazo)resorcinolato (PAR) complex with microwave heating was achieved. Though it required more than 100 min for completing the complexation reaction of Cr(III) with 4-(2-pyridylazo)-resorcinol by heating with a hot-water bath, the reaction was completed within 2 mm by microwave heating with a household microwave oven. The successful application of the acceleration of the complexation reaction by microwave heating to the derivatization of the determination method for trace Cr(III) by a pre-column derivatized ion-pair reversed-phase partition high-performance liquid chromatography was also accomplished. A detection limit as low as 7.7 nM was achieved, and a successful application of the proposed method to the determination of Cr(III) in the certified reference material of a river-water sample, JSAC 0302-3b, was also performed.