Technical note: Using UV-Vis spectrophotometry to estimate nitrite plus nitrate and monochloramine

Use of ultraviolet‐visible (UV‐Vis) spectrophotometry in analytical chemistry is wellestablished, and the application of this technique to the study of water and wastewater has recently been summarized (Thomas & Burgess, 2007). The use of chloramination in the United States is increasing because of concerns about the formation of chlorination by‐products. This study proposes a method to produce estimates of the sum of nitrite and nitrate concentration as well as monochloramine from UV‐Vis spectrophotometry (ranging from 200 to 320 nm) in these systems with grab samples. This is an empirical method based on multiple linear regressions and absorbances measured at the wavelengths of 220, 245, 280, and 320 nm. The methodology has application potential for continuous on‐line monitoring.