Application of In-Syringe Dispersive Liquid–Liquid Microextraction Coupled to GC/FID for Determination of Trace Contamination of Phthalate Esters in Water Samples

In this work, a simple and easy to handle one-step in-syringe setup for the dispersive liquid–liquid microextraction method has been developed for preconcentration of trace quantities of four kinds of phthalate esters (PEs) in water samples as a prior step to its determination by gas chromatography/flame ionization detector. The environmental pollution at this method has been limited due to using a glass syringe as extraction unit and also a very small amount of n-hexane as a safe solvent. Some important parameters such as the type of extraction and disperser solvents, extraction and disperser solvents volume, sample volume and ionic strength were investigated and optimized. Validation experiments showed that the optimized method had precision (1.7–6.9%) and high recovery (94.32–104.7%), and the limits of detection were from 0.406 to 1.33 µg L−1. At the end, the method was successfully applied for the determination of PEs in real water samples.