Simultaneous determination of bifenox, dichlobenil and diclofop methyl by hollow carbon nanospheres enhanced magnetic carboxylic multi-walled carbon nanotubes

Wen-Kui Li; Hai-Xia Zhang; Yan-Ping Shi

doi:10.1016/j.aca.2018.01.030

Simultaneous determination of bifenox, dichlobenil and diclofop methyl by hollow carbon nanospheres enhanced magnetic carboxylic multi-walled carbon nanotubes

Anal Chim Acta. 2018 Jun 29:1011:40-49. doi: 10.1016/j.aca.2018.01.030. Epub 2018 Jan 31.

Authors

Wen-Kui Li¹, Hai-Xia Zhang², Yan-Ping Shi³

Affiliations

¹ CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China; University of Chinese Academy of Sciences, Beijing 100039, PR China.
² College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China.
³ CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China. Electronic address: shiyp@licp.cas.cn.

PMID: 29475484
DOI: 10.1016/j.aca.2018.01.030

Abstract

A novel analytical method based on magnetic solid-phase extraction (MSPE) coupled with high performance liquid chromatography-diode array detection (HPLC-DAD) was established for three herbicides simultaneous determination. The key of the method was the explored extractant, which was a composite of hollow carbon nanospheres (HCSs) enhanced magnetic carboxylic MWCNTs (HCSs@Fe₃O₄-MWCNTs-COOH). MWCNTs-COOH was inserted in the pores of HCSs by oscillation and sonication with the capillary forces, making the carboxylic groups and structure intervals of the composite increase as compared to MWCNTs-COOH, therefore the extractant exhibited enhanced hydrophilicity, dispersibility, adsorptivity and selectivity. The extractant was sensitive to analytes with the structure of multi-aromatic ring, more hydrogen bond acceptor and large molecular polar surface area, which can be attributed to hydrogen bonding and π-π electron-donor-acceptor (EDA) interactions. The morphology, structure and magnetic property of the extractant were characterized. Then the explored extractant based MSPE-HPLC-DAD method was applied for bifenox (BFO), dichlobenil (DCB) and diclofop methyl (DCM) determination from wheat flour samples. Prior to real sample analysis, critical extraction parameters such as solution pH, extraction time, salt addition and temperature were investigated and optimized, and the analytical method was evaluated. It was indicated that the method had satisfactory linearities with the linear coefficients above 0.99, good precision with the RSD less than 3.5%, desirable recoveries ranged from 88.8% to 96.6%, and low limits of detection (LOD) that were 0.39, 0.24, and 0.68 ng/g for DCB, BFO and DCM, respectively. The established MSPE-HPLC-DAD method has great potentials for trace polar herbicides selective determination from complex matrix samples.

Keywords: High performance liquid chromatography; Hollow carbon nanospheres; Magnetic carboxylic multi-walled carbon nanotubes; Magnetic solid-phase extraction; Wheat flour.