Activation of promutagenic N-nitrosomorpholine and other N-nitrosoalkylamines by near-ultraviolet irradiation in the presence of phosphates.

When a neutral solution of N-nitrosomorpholine, N-nitrosopyrrolidine, or N-nitrosopiperidine was irradiated with near-ultraviolet light, the solution became mutagenic to Salmonella typhimurium TA100 in the absence of metabolic activation. The formation of the active compounds required the presence of phosphate or its esters such as adenosine 5'-triphosphate during the irradiation.