Alkaline hydrolysis of high-molecular-mass (10 MDa) linear polyacrylamide, a widely used replaceable sieving medium for the capillary electrophoresis of DNA fragments and proteins, was investigated. The release rate of ammonia, a product of amide group hydrolysis, was monitored by a high-sensitivity continuous-flow system. The experimental results show a rapid onset of hydrolysis at a temperature of 70 degreesC. While the degree of 1 h hydrolysis was evaluated to reach about 16% at 70 degreesC and pH 13, it drops to 5% at 50 degreesC and pH 12.5.