Automated dispersive liquid-liquid microextraction technique for the analysis of N-nitrosamines in water

An automated dispersive liquid-liquid microextraction method of detecting and quantifying one or more N-nitrosamines, comprising:

• (a) extracting an aqueous solution comprising the one or more N-nitrosamines by mixing an extraction solvent and a dispersive solvent with the aqueous solution, wherein the one or more 1-nitrosamines, or a portion thereof, re-distribute from the aqueous solution to the extraction solvent, wherein the mixing comprises sonicating the mixture of the extraction solvent, the dispersive solvent, and the aqueous solution,
• (b) permitting the resulting mixture in (a) to form a two-phase mixture comprising an aqueous phase comprising the aqueous solution with reduced amounts of the one or more N-nitrosamines and an organic phase comprising the extraction solvent with the one or more N-nitrosamines extracted from the aqueous solution,
• (c) injecting the organic phase, or a portion thereof, into an injection port of a gas chromatograph coupled with at least one mass spectrometer, and
• (d) analyzing the one or more N-nitrosamines by gas chromatography and mass spectrometry to detect and quantify the concentration of the one or more N-nitrosamines in the aqueous solution, wherein:
• a volume ratio of the extraction solvent to the dispersive solvent is in a range of 80:1 to 10:1.