A rapid solid phase extraction (SPE) method was developed to analyze volatile N-nitrosamines (NAm) in foods. The currently used vacuum distillation technique is time and solvent consuming and is cumbersome for multiple analyses. Our objective was to develop a robust analytical method to measure the eight most common volatile NAm found in foods. The extraction procedure was based on two consecutive extraction/concentration steps using Extrelut and Florisil SPE. The amounts of food sample and solvent required were reduced compared to the conventional vacuum distillation method without affecting the sensitivity which was at a 0.3 ppb detection limit. A greater confidence in the analyte detection was obtained by the use of a capillary GC column, instead of the conventionally used open packed column, prior to thermal energy analyzer (TEA) detection. Another advantage of our method is the use of commercial cartridges, which ensures reproducibility and standardization of the method for multiple analyses. An application of the SPE method to a survey of volatile NAm content in sausages and dried milk powder revealed no contamination (<0.3 ppb) of either of these food samples.

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Abstract:Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and air action. The paper presents firstly the laboratory degradation of a first batch of fluorescent tracers in contact with chlorine, in order to simulate their passage through a water treatment system for human consumption. A second batch of the same tracers is subjected to agents of natural degradation: ultraviolet illumination, sunlight and air sparging. Most tracers is degraded, and toxicity and ecotoxicity tests (on rats, daphniae and algae) are performed on degradation byproducts. These tests do not show any acute toxicity but a low to moderate ecotoxicity. In conclusion, the most used fluorescent tracers of the Normandy karstic chalk and their artificial and natural degradation byproducts do not exhibit significant toxicity to humans and the aquatic environment, at the concentrations generally noted at the restitution points.

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