This article reports an improved headspace gas chromatographic (HS-GC) technique for the determination of monomers in polymer latex. The method is based on a HS-GC technique reported previously (Chai et al., J Appl Polym Sci 2006, 99, 392) but includes a major modification in the method of sample preparation. By using a weight-based sampling method, coupled with initial dissolution in dimethyl sulfoxide (DMSO), followed by water dilution, the uncertainty in the sample preparation associated with previous method can be significantly reduced. The improved method is reliable, practical, and suitable for use in the kinetic study during emulsion polymerization. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012