A method for monitoring a chemical component in an industrial water system comprises irradiating a liquid sample from an industrial water system, containing at least one chemical component to be monitored, with light from an excitation light source. Room temperature phosphorescence emitted from the sample is detected after irradiation. The concentration of the chemical component to be monitored is then calculated from the detected room temperature phosphorescence. The liquid sample includes at least one room temperature phosphorescent material (RTPM) and at least one heavy atom perturber (HAP) dissolved therein. The HAP is present in the sample at a concentration sufficient to induce phosphorescence activity in the RTPM. The liquid sample is irradiated in a manner sufficient to induce the RTPM within the sample to emit room temperature phosphorescence, and the calculated concentration of the chemical component to be monitored is a function of the room temperature phosphorescence intensity or temporal metric. A phosphorimeter for measuring room temperature phosphorescence is also described.