High-density solvent-based de-emulsification microextraction technique combined with fiber optic-linear array detection spectrometry for fast determination of ppb-level phenol index

Abstract

In this work, a simple, rapid, and efficient solvent-based de-emulsification microextraction technique using high-density solvent has been developed for determining phenol index in water samples for the first time. The extraction of phenolic compounds in the aqueous sample solution was performed by using chloroform (as extraction solvent) and acetone (as dispersive solvent) in the presence of 4-aminoantipyrine (4-AAP) as chromogenic reagent. A de-emulsification solvent (ACN) was then injected into the sample solution to break up the emulsion, and then obtained emulsion cleared into two phases quickly, with no centrifugation step. The lower layer organic phase transferred into a microcell of a fiber optic-linear array detection spectrophotometry. The effect of various parameters on the extraction recovery was investigated. Under the optimized conditions and preconcentration of 10 mL of sample, the enhancement factor of 140 and the detection limit of 0.6 μg L⁻¹ were obtained. Validation of the method was performed by spiking recovery method and comparison of results with those obtained by American Society for Testing and Materials standard method.

Keywords:

• Fiber optic-linear array detection spectrophotometry
• Phenol index
• High-density solvent based de-emulsification microextraction technique
• Water samples