Thus, HS-SPME method was applied to achieve integrated extraction
and concentration into one step in this study. Several
parameters such as salting out effect, extraction time, and extraction
temperature were optimized for the best extraction effi-
ciency of n-nitrosamines. 75 mm CAR/PDMS fiber, which has been
reported as an optimal fiber for the n-nitrosamine analysis in the
previous studies [4,14], was selected for the experiment and head
space volume was set by keeping the sample volume at 2 mL. It
was estimated that adding salt to SPME sample decreases the
solubility of analytes in the aqueous phase by shifting equilibrium
towards the air phase [4].