Magnetic Graphene Nanoparticles for the Preconcentration of Chloroacetanilide Herbicides from Water Samples Prior to Determination by GC-ECD

Abstract

A highly sensitive method for the determination of the chloroacetanilide herbicides alachlor, acetochlor, pretilachlor, butachlor, and metolachlor in environmental water samples was developed. It is based on solid-phase extraction using magnetic graphene nanocomposite (G-Fe₃O₄) as the adsorbent, followed by gas chromatography with electron capture detection. This novel adsorbent showed a great adsorptive ability toward the analytes. The main experimental parameters such as the amount of G-Fe₃O₄, extraction time, ionic strength, the pH of the sample solution, and desorption conditions were optimized. Under the optimum conditions, the enrichment factors of the method for the analytes were in the range from 649 to 1078. A good linear response was achieved in the range of 0.2–20.0 ng mL⁻¹, with correlation coefficients (r) varying from 0.9964 to 0.9998. The limits of detection of the method ranged from 0.02 to 0.05 ng mL⁻¹ and the relative standard deviations were below 4.5%. The method was successfully applied to the determination of the herbicides in environmental water samples. Recoveries of the method for the analytes were in the range of 80.7–105.3%.

Keywords:

• Chloroacetanilide herbicides
• Gas chromatography
• Magnetic graphene nanocomposite
• Magnetic solid-phase extraction

Acknowledgments

Financial support both from the National Natural Science Foundation of China (No. 31171698) and from Hebei province science and technology support program (No. 12396908D) is gratefully acknowledged.

Notes

LR, linear range.

^a R, recovery of the method.

^b nd, not detected.