Thesis (M.Sc.)--Chulalongkorn University, 1998

In this study, high performance liquid chromatography with photodiode array detector was firstly proposed for the speciation of inorganic mercury(II), methylmercury, and phenylmercury using the combination of complexing agent and ion-pairing agent in mobile phase. Two mobile phase systems were investigated as the effective mobile phases for the speciation. The affected parameters on the separation and sensitivity were optimised. Inorganic mercury and methylmercury can successfully be separated within eight minutes using methanol-water (12:88% v/v) buffered with acetate buffer pH 3.00 containing 0.0075 M tetrabutylammonium bromide and 0.0050% v/v 2-mercaptoethano. The separation of inorganic mercury, methylmercury, and phenylmercury can be achieved within fourteen minutes using methanol-water (40:60% v/v) buffered with acetate buffer pH 5.00 containing 0.0040 M sodium hexanesulfonate and 0.0040% v/v 2-mercaptoethanol. The relative standard deviations of both systems were less than the acceptable values of the reference method. The detection limits of mercury commounds were also evaluated.