Magnetic dispersive solid‐phase extraction based on graphene oxide/Fe₃O₄@polythionine nanocomposite followed by atomic absorption spectrometry for zinc monitoring in water, flour, celery and egg

Abstract

BACKGROUND: Magnetic graphene oxide nanocomposite has been proposed as a promising and sustainable sorbent for the extraction and separation of target analytes from food matrices. Sample preparation based on nanocomposite presents several advantages, such as desired efficiency, reasonable selectivity and high surface-area-to-volume ratio. RESULTS: A new graphene oxide/Fe 3 O 4 @polythionine (GO/Fe 3 O 4 @PTh) nanocomposite sorbent was introduced for magnetic dispersive solid-phase extraction and flame atomic absorption spectrometric detection of zinc(II) in water, flour, celery and egg.To fabricate the sorbent, an oxidative polymerization of thionine on the surface of magnetic GO was applied, while polythionine was simply employed as a surface modifier to improve extraction yield. The properties of the sorbent were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, vibrating sample magnetometry and Fourier transform-infrared spectroscopy. The calibration curve showed linearity in the range of 0.5-30 ng mL −1 . Limits of detection (S/N = 3) and quantification (S/N = 10) were 0.08 and 0.5 ng mL −1 , respectively. CONCLUSION: The method was applied for trace-level determination of Zn(II) in water and food samples, and its validation was investigated by recovery experiments and analyzing certified reference material. Effect of ionic strengthAddition of electrolyte to the sample increases the ionic strength, and thus improves the extraction yield, which is due to the salting-out influence. Thus different concentration levels of NaCl (0-10% w/v) were added to the sample solution to investigate J Sci Food Agric 2018; 98: [3571][3572][3573][3574][3575][3576][3577][3578][3579]

Developing a highly selective method for preconcentration and determination of cobalt in water and nut samples using 1‐(2‐pyridylazo)‐2‐naphthol and UV–visible spectroscopy

“…In order to achieve this aim, many extraction methods have been proposed . Cloud‐point extraction, liquid–liquid extraction, dispersive liquid–liquid extraction, and magnetic solid‐phase extraction (MSPE) are some of the preconcentration methods . In the MSPE method, the adsorbent has magnetic properties, and it can be easily separated from the matrix by using a magnet without the need for centrifugation or filtration .…”

“…[14][15][16] Cloud-point extraction, liquid-liquid extraction, dispersive liquid-liquid extraction, and magnetic solid-phase extraction (MSPE) are some of the preconcentration methods. 17,18 In the MSPE method, the adsorbent has magnetic properties, and it can be easily separated from the matrix by using a magnet without the need for centrifugation or filtration. [19][20][21] Nanocomposites have attracted researchers' interests as sorbents.…”

Magnetic Solid-Phase Extraction of Organic Compounds Based on Graphene Oxide Nanocomposites

“…Due to its superior properties such as good thermal and mechanical stability as well as its high surface area, graphene oxide has been used in multiple scientific fields including heterogenous catalysis, gas sorption, storage and separation, sensors and drug delivery [25].In analytical chemistry, GO has been successfully employed for the sample preparation of a wide variety of samples including biological, food and environmental matrices [26][27][28]. Graphene oxide consists of one-atom-thick two-dimensional layers of sp 2 -bonded carbon and the material is rich in oxygen-containing groups including hydroxyl, carboxyl and epoxy groups, which assist the interaction between the sorbent and organic molecules through strong π-π stacking, hydrophobic interaction and hydrogen bonding [29][30][31].Graphene oxide is an ultra-light material that poses high dispersibility in aqueous solutions as well as high hydrophilicity which makes its separation from this kind of solutions difficult. In order to improve the separation, GO can form magnetic nanocomposites with magnetite through electrostatic interaction between the negatively charged graphene oxide sheets and the positively charged surface of Fe 3 O 4 [32].…”

“…">Nanocomposites of GO with Fe 3 O 4 NanoparticlesDue to its high surface area and its superparamagnetic properties GO/Fe 3 O 4 has been employed for the extraction of a wide variety of organic compounds from various samples. The surface of magnetic graphene oxide is rich in hydroxyl and carboxyl groups, which assist the interaction between the sorbent and the target analytes through strong π-π stacking, hydrophobic interaction as well as hydrogen bonding [26][27][28][29][30][31]. Figure 1 shows the structure of graphite, graphene oxide, reduced graphene oxide, and magnetic graphene oxide.…”

“…In analytical chemistry, GO has been successfully employed for the sample preparation of a wide variety of samples including biological, food and environmental matrices [26][27][28]. Graphene oxide consists of one-atom-thick two-dimensional layers of sp 2 -bonded carbon and the material is rich in oxygen-containing groups including hydroxyl, carboxyl and epoxy groups, which assist the interaction between the sorbent and organic molecules through strong π-π stacking, hydrophobic interaction and hydrogen bonding [29][30][31].…”