USEPA Method 603 was modified and evaluated with newly established chromatographic conditions for the determination of acrolein, acrylonitrile, and acetonitrile. Method detection limits (MDLs) for the new chromatographic conditions were found to be equivalent to those previously specified in Method 603 for acrolein and acrylonitrile (0.7 and 0.5 micrograms/l, respectively). The method detection limit found for acetonitrile in this work was 2.7 micrograms/l. The method was found to be accurate and precise for the determination of all three method parameters. Recoveries and precisions were determined at two spiking levels in each of three matrices, namely, reagent water, Columbus Publicly Owned Treatment Works (POTW) wastewater, and industrial wastewater. Acrolein was not stable in the industrial wastewater even though the water was buffered at pH 4.5 before spiking. For the other two matrices, the acrolein recovery ranged from 80 to 104% (average, 94%) and the precisions ranged from 1 to 4% relative standard deviation (RSD) (average, 3% RSD). The loss of acrolein due to apparent chemical degradation in the industrial wastewater underscores the current lack of understanding of the chemical factors that control the stability of acrolein in aqueous systems.