Ultra-preconcentration of common herbicides in aqueous samples using solid phase extraction combined with dispersive liquid–liquid microextraction followed by HPLC–UV

Abstract

An analytical method, solid-phase extraction combined with dispersive liquid–liquid microextraction (SPE–DLLME), was established to extract and determine the herbicides in aqueous samples. In this method, herbicides were adsorbed from a large volume of aqueous samples (100 mL) into 500 mg functionalized octadecyl silica (C₁₈) sorbent. After the elution of the desired compounds from the sorbent by using acetone, DLLME technique was performed on the obtained solution. Under the optimum conditions, the calibration graphs are linear in the range of 0.02–10 µg L⁻¹ and limits of detection (LODs) are in the range of 0.003–0.006 µg L⁻¹. The relative standard deviations (RSDs, for 0.50 µg L⁻¹ of 2,4-D and alachlor, and 1.00 µg L⁻¹ of atrazine in water) are in the range of 6.1–8.1% (n = 5). The SPE–DLLME provided a high enrichment factor (1725–2065) for herbicides.

Keywords:

• Dispersive liquid–liquid microextraction
• solid-phase extraction
• alachlor
• 2,4-D
• atrazine
• water analysis

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors thank the Deputy of Research and Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran [89006] for financial support.