MgO-ZnO/carbon nanofiber nanocomposite as an adsorbent for ultrasound-assisted dispersive solid-phase microextraction of carbamazepine from wastewater prior to high-performance liquid chromatographic detection

Malesela William Lekota,K Mogolodi Dimpe,Philiswa Nosizo Nomngongo

doi:10.1186/s40543-019-0185-1

Abstract

A simple, rapid, and efficient ultrasound-assisted dispersive solid-phase microextraction (UA-DSPME) method was developed for the preconcentration of carbamazepine (CBZ) in wastewater prior to high-performance liquid chromatography coupled with diode array (HPLC-DAD) determination. The carbon nanofibers coated with magnesium oxide-zinc oxide (MgO-ZnO@CNFs) nanocomposite was used as an efficient adsorbent in magnetic dispersive solid-phase microextraction method. The structural and morphological properties of the nanocomposite were characterized by scanning electron microscopy and energy dispersive spectroscopy, transmission electron microscopy, X-ray diffractometer, and Fourier transform infrared spectroscopy. The surface area was investigated using Brunauer–Emmett–Teller. Several factors (such as pH, mass of adsorbent, extraction time, and eluent volume) that affect extraction and preconcentration of CBZ were also assessed and optimized using response surface methodology based on central composite design. Under optimal conditions, the limits of detection (LOD) and quantification were 0.08 μg L−1 and 0.29 μg L−1, respectively. The calibration curve constructed after preconcentration of seven successive standards was linear in the concentration range of 0.3–800 μg L−1 with the correlation coefficient of 0.9922. The intra-day and inter-day precisions expressed in terms of relative standard deviation were 1.4% and 4.2%. A preconcentration factor of 490 was achieved, and the method was applied for the analysis of spiked wastewater. Satisfactory recoveries ranging from 97.8 to 102% were obtained.

Highlights

In the last decades, there have been more reports of pharmaceutical compounds that are present in rivers and surface waters at large (Andreozzi et al 2002)
The peaks at 37.3° (111) and 74.9° (311) were assigned to Mg(OH)2. This X-ray diffraction (XRD) is in total agreement with JCPDS 89-7746 (Dhineshbabu et al 2014), and the crystals correspond to the cubic system with unit cell length as 4.21 Å
An efficient ultrasound-assisted dispersive solid-phase microextraction was developed as sample pretreatment method for extraction and preconcentration of carbamazepine in wastewater samples prior to analysis by Analytical figures of merit

Summary

Introduction

There have been more reports of pharmaceutical compounds that are present in rivers and surface waters at large (Andreozzi et al 2002). Lekota et al Journal of Analytical Science and Technology (2019) 10:25 expired medicine contribute to pollution (Murdoch 2015). Some of these pharmaceutical compounds or their metabolites are very stable and mobile in natural environmental conditions (Murdoch 2015). Since the water treatment plants fail to remove them, they can be deposited into the soil which may reach the agricultural land (Larsen et al 2004). Through intensive studies all over the world in the last few decades, some pharmaceutical compounds have been successfully detected in groundwater (Heberer 2002a; Heberer 2002b; Sacher et al 2001)

Methods

Results

Conclusion