Ozonation Byproducts. 2. Improvement of an Aqueous-Phase Derivatization Method for the Detection of Formaldehyde and Other Carbonyl Compounds Formed by the Ozonation of Drinking Water

摘要

A method for the determination of low molecular weight aldehydes in water using aqueous-phase derivization with 0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride has been improved by the use of high-resolution capillary GC. Detection limits with GC/ECD and GC/MS with selected ion monitoring are in the low microgram per liter (ppb) range. The method has been used to evaluate levels of aldehydes in three surface water treatment plants and one ground water treatment plant before and after ozonation. Aldehydes are increased as a result of ozonation, with formaldehyde being the most prevalent. Higher yields are observed in the plant treating surface water with the highest TOC level, but very low yields are observed in a high TOC ground water. Spiking studies show that the raw ground water has a very high demand for formaldehyde, suggesting that the aldehydes may be converted into secondary byproducts.