RPHPLC Determination of Raw Materials of Synthetic Polycarboxylic Water Reducing Agent

A method of RPHPLC was proposed for the simultaneous determination of “macromonomers”, raw materials of synthetic polycarboxylic water reducing agent, including methacrylic acid (MA), poly (ethylene glycol) monomethyl ether (MPEG) and methoxy (polyethyleneglycol) methacrylate (MPEG-MA). ZORBAS 300SB-C18 column was used as stationary phase for separation, and mixtures of methanol and (φ) 0.1% trifluoroacetic acid of pH 2.0 in different ratios were used as mobile phase in the gradient elution. The content of MA was determined by UV-detection at the wavelength of 218 nm; and the contents of MPEG and MPEG-MA were determined by evaporation light detector with the temperature of drift tube at 80 ℃ and flow rate of carrier gas at 1.2 L·min-1, respectively. It was found that the residual amounts of 3 macromonomers were quite different.