Novel Zeolitic Imidazolate Frameworks Based on Magnetic Multiwalled Carbon Nanotubes for Magnetic Solid-Phase Extraction of Organochlorine Pesticides from Agricultural Irrigation Water Samples

Xiaodong Huang,Shuning Zheng,Haixiang Gao,Lingyun Li,Xiaomin Xu,Donghui Xu,Huan Lin,Guangyang Liu

doi:10.3390/app8060959

Abstract

Magnetic solid-phase extraction is an effective and convenient sample pretreatment technique that has received considerable interest in recent years. A lot of research indicated that magnetic nanocarbon-material-based composites have good application prospects as adsorbents for magnetic solid-phase extraction of pesticides. Herein, a novel zeolitic imidazolate framework based on magnetic multiwalled carbon nanotubes (M-M-ZIF-67) has been prepared as an adsorbent for magnetic solid-phase extraction of nine organochlorine pesticides from agricultural irrigation water samples. The obtained M-M-ZIF-67 material possessed porous surfaces and super-paramagnetism due to the utilization of magnetic multiwalled carbon nanotubes as the magnetic kernel and support. To evaluate the extraction performance of the M-M-ZIF-67, the main parameters that affected the extraction efficiency were researched. Under the optimal conditions, a good linearity for the nine organochlorine pesticides was achieved with the determination coefficients (R2) higher than 0.9916. The limits of detection (signal/noise = 3:1) were in the range 0.07–1.03 µg L−1. The recoveries of all analytes for the method at spiked levels of 10 and 100 µg L−1 were 74.9–116.3% and 75.1–112.7%, respectively. The developed M-M-ZIF-67 based magnetic solid-phase extraction method has a potential application prospect for the monitoring of trace level of organochlorine pesticides in environmental water samples.

Highlights

Sample pretreatment is a crucial step in analysis of trace or ultra-trace amounts analytes in complex matrices
The micro-morphologies of the Fe3 O4 –Multiwalled carbon nanotubes (MWCNTs) and M-M-Zeolitic imidazolate frameworks (ZIFs)-67 were observed by SEM and TEM
The magnetic hysteresis loops show that both the remanence and coercivity values of the three types of magnetic materials are zero, which indicates that they have typical supermagnetic properties and could be separated using an external magnet

Summary

Introduction

Sample pretreatment is a crucial step in analysis of trace or ultra-trace amounts analytes in complex matrices. Solid-phase extraction (SPE) is a type of widely used pretreatment for effective concentration of analytes in complex matrices before instrumental analysis [1]. A variety of pretreatment methods has been developed based on this technique, including solid-phase microextraction (SPME) [2], micro-SPE (μ-SPE) [3], and stir-bar sorptive extraction (SBSE) [4]. Magnetic solid-phase extraction (MSPE), as a new type of SPE, is a pretreatment method that has received considerable interest in recent years. In this technique, magnetic adsorbents are directly.

Methods

Results

Conclusion