The nuclear magnetic resonance chemical shifts of the lower polyphosphate compounds are strongly dependent on the hydrogen ion concentration of the solution, both absolutely and relative to each other. At an optimum pH, the chemical shifts of pyrophosphate and tripolyphosphate will be most widely separated, and these two compounds can be determined in the presence of each other and in the presence of higher polyphosphates. The univariate simplex procedure found the optimum pH in ten trials, but required two more measurements to define the minimum width of the maximum response region, pH 8.4 to 8.7