A New “Mix and Measure” Method for Rapid Quantitative Determination of Alkalinity Based on Proton Equilibrium and Definite Integral of Buffer Capacity

Alkalinity is crucial in environmental control of ecosystems, wastewater and drinking water treatment, and industrial process control. In this work, we reported a new equation for calculating alkalinity based on the definition of buffer capacity in acid-base buffer solutions and the quantitative relationship between the buffer capacity and pH changes. A "mix and measure" method was developed using this new equation, involving mixing a solution with unknown alkalinity and a standard solution in a specific volume ratio, followed by measuring the pH after mixing. The alkalinity of the solution can be calculated using the newly developed equation. The "mix and measure" method is much more efficient than traditional titration methods for determination of alkalinity because it is restricted by the titration stoichiometric point. Additionally, we demonstrated the rapid determination of the alkalinity for a series of solutions using a portable detection system. This system exhibited precision and accuracy comparable to those of traditional titration methods. The portable system offers great potential for the on-site and real-time determination of alkalinity for industrial control and environmental monitoring purposes.