Fullerenes for aromatic and non-aromatic N-nitrosamines discrimination
2009
Jurado-Sánchez, Beatriz | Ballesteros, Evaristo | Gallego, Mercedes
The detection of N-nitrosamines (NAms) in water supplies is an environmental and public health issue because many NAms are classified as probable human carcinogens. Non-aromatic (aliphatic and cyclic) NAms are more toxic than aromatic ones as their maximum admissible concentration is limited in drinking water (20-2000ngL⁻¹). From that premise, a simple and novel method to discriminate between both fractions of NAms according to their toxicity was proposed. An automatic solid-phase extraction unit containing two sequential sorbent columns was constructed. A sample volume of 25mL was passed through a C₆₀ fullerene column in which only the aromatic fraction was retained, and the effluent was then passed through a Merck LiChrolut EN column where the non-aromatic fraction was retained. Following elution of the non-aromatic NAms with 150μL of ethyl acetate-acetonitrile (9:1), 1μL of the extract was injected into a GC/MS. A comparative study of C₆₀ and C₇₀ fullerenes and nanotubes revealed C₆₀ fullerene to be the best choice to selectively retain the aromatic fraction. The method exhibits a linear range of 15-20,000ngL⁻¹; limits of detection of 4-15ngL⁻¹; and an RSD of ~5%. Recoveries throughout the whole method were between 95% and 102% for six non-aromatic NAms spiked into several types of waters. Our study demonstrates that a simple and fast SPE system (10min per sample) with a customary GC-MS instrument permits the quantification of these amines in complex matrices with considerable sensitivity and selectivity.
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