A method has been developed and analytically validated for the analysis of purgeable mercury in caustic nuclear waste. Using multivariate optimization method, purge flow rate was determined to be highly correlated with increased response (p =0.023). Total recovery of spiked purgeable mercury from deionized water was 99.4 +/- 10.6% and 91.6 +/- 14.9% from spiked high-activity tank waste samples. Calibration, by external calibration and standard addition calibration, maintained a mean accuracy of 101 +/- 5% and 99.9 +/- 1.7%, respectively. This method represents a decrease in sample handling and processing over currently standard methods and represents a more amenable method for purgeable mercury analysis in liquid nuclear waste. This validated method has been applied to liquid waste samples from high-activity waste tanks at Savannah River Site.