Mustafa Tuzen

Simple and green switchable dispersive liquid–liquid microextraction of cadmium in water and food samples

A green, switchable water dispersive liquid–liquid microextraction (SWDLL-ME) method is introduced for the first time as a preconcentration/separation tool for measuring trace levels of cadmium (Cd) in real water and food samples. In the present study, a switchable aqueous solution of polar organic solvent (acetonitrile) was reversibly switched (on and off) from miscible monophasic to immiscible biphasic in aqueous medium by exposure to an anti-solvent trigger (CO2). The developed SWDLL-ME was successfully applied as an extraction method for the extraction of a Cd–PAN complex (1-(2-pyridylazo)-2-naphthol) in polar organic solvent (PS). The solvent enriched phase containing Cd–PAN was separated from the switchable water (SW) and treated with 200 μL of 0.1 mol L−1 HNO3 with ethanol (1u2006:u20061, v/v) in order to reduce its viscosity, and it was then easily injected into a GFAAS for analysis. The SW was reused for the next assay after the removal of CO2. The switching phenomenon of the SW from low to high polarity was confirmed by FTIR spectroscopy and conductivity measurements. The enrichment factor and limit of detection of the proposed method were 22 and 0.38 ng L−1, respectively. Validation of the developed method was carried out by analyzing certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves).

Response surface optimization, kinetic and thermodynamic studies for effective removal of rhodamine B by magnetic AC/CeO2 nanocomposite

The activated carbon (AC) was obtained from waste scrap tires and modified by bimetallic Fe and Ce nanoparticles in order to combine both the high surface area and the active sites for enhanced adsorption of the dye. The produced nanocomposite was used as a novel cost-effective magnetic in rhodamine B (RhB) removal from aqueous solutions. The FT-IR, SEM, EDX, TEM, and surface area analysis methods were implemented to characterize the morphological, chemical, thermal and surface properties of the developed adsorbent. The optimum batch experimental conditions were found under the response surface methodology. The adsorption equilibrium data were well fitted by the Langmuir isotherm model. The adsorption capacity was 324.6xa0mgxa0g-1. The kinetic and thermodynamics studies were also carried out to understand the adsorption mechanism. The study indicated that RhB adsorption by the AC/Fe/Ce magnetic adsorbent has an endothermic character and followed the pseudo-second-order kinetics model. By using ethanol solution, RhB was desorbed at high efficiency and the prepared material could be recycled for up to ten cycles. Thus, the magnetic nanocomposite is an effective and promising adsorbent for the cleaning treatment of RhB ions from wastewater by a large scale designed adsorption system.

Polyamide magnetic palygorskite for the simultaneous removal of Hg(II) and methyl mercury; with factorial design analysis

A novel efficient adsorbent was prepared by the modification of magnetic palygorskite (MPG) by polyamide via the interfacial polymerization of trimesoyl chloride with m-phenylenediamine. The prepared magnetic palygorskite modified with polyamide (MPGP) material was appraised for its removal of the Hg(II) and CH3Hg species from aqueous solutions. The developed adsorbent was characterized using spectroscopic techniques. The adsorption ability of the MPGP sorbent was systematically investigated by using the batch method. Factorial design analysis was applied to study the effect of different batch parameters on the adsorption yield of both mercury species. These factors include mercury concentration, initial pH, sorbent amount and contact time. The equilibrium data coincided with the Langmuir adsorption isotherm indicating the maximum adsorption capacity of the MPGP was determined as 211.93u202fmg/g for Hg(II) and 159.73u202fmg/g for CH3Hg. The kinetic mechanism of the adsorption of both mercury species was well defined by the pseudo-second-order while the adsorption processes demonstrated spontaneity and an exothermic character at the studied temperatures. The cycling adsorption/desorption tests made by using a 1u202fmol/L HCl solution demonstrated that the MPGP had good reusable performance up to seven cycles. Based on the results it can be suggested that the synthesized MPGP sorbent can be handled for the elimination of Hg(II) and CH3Hg from wastewater effluents.

Deep eutectic solvent based advance microextraction method for determination of aluminum in water and food samples: Multivariate study

Preconcentration of aluminum Al3+ was carried out by a novel deep eutectic solvent based ultrasound-assisted liquid phase microextraction (DES-UALPME) method. The deep eutectic solvents (DESs), a green solvent was first time used for enrichment and quantification of very low concentration of Al3+ in water and food samples, prior to analysed by electrothermal atomic absorption spectrometry (ETAAS). In present method it was observed that % recovery of Al-8-hydroxyquinoline chelates efficiently extracted by DES solvent. Pre-enrichment factor and limit of detection were observed to be 50, and 0.032μgL-1, respectively. Developed procedure was validated with the CRM (SLRS-5 river water) of Al and a good agreement was observed in results of measured value to the certified value. The RSD was calculated as 3.3%. The presented procedure was successfully carried out to different water and food samples.

Vortex-Assisted Solidified Floating Organic Drop Microextraction of Molybdenum in Beverages and Food Samples Coupled with Graphite Furnace Atomic Absorption Spectrometry

A simple, rapid, sensitive, and selective vortex-assisted solidified floating organic drop microextraction (VA-SFODME) method was developed for the determination of molybdenum in beverages and food samples by using graphite furnace atomic absorption spectrometry (GFAAS). 4-Amino-3-hydroxy-1-naphthalenesulfonic acid (AHNA) was used as complexing reagent. 1-Undecanol was used as extraction solvent. Analytical parameters were investigated and optimized as pH 5, ligand amount 1 mg, volume of 1-undecanol 100xa0μL, extraction time 4xa0min, and sample volume 20xa0mL. Under optimum conditions, enrichment factor (EF) and limit of detection (LOD) for Mo(VI) were found to be 133 and 10xa0ngxa0L−1, respectively. The relative standard deviation (RSD) was found to be 2.5xa0%. Matrix effects of some cations, anions, and transition metal ions were also investigated. The accuracy of the VA-SFODME method was confirmed by the analysis of certified reference materials (NIST SRM 1568a rice flour, GBW 07605 tea, and NIST SRM 1577b bovine liver). Optimized method was successfully applied to beverages and food samples after microwave digestion method.

A new green switchable hydrophobic–hydrophilic transition dispersive solid–liquid microextraction of selenium in water samples

A novel switchable hydrophobic–hydrophilic transition dispersive solid–liquid microextraction (SHT-DSLME) method has been used for the first time as a dispersive/extractive method for the removal of total selenium from real samples. Tetraethylenepentamine modified multi-walled carbon nanotubes (MWCNTs-TEPA) were synthesized and employed as an adsorbent for the removal and analysis of total inorganic selenium by SHT-DSLME coupled with graphite furnace atomic absorption spectrometry (GFAAS). In this study, the hydrophobic–hydrophilic transition of MWCNTs-TEPA was achieved by exposing them to a green, inexpensive, non-hazardous and non-accumulating antisolvent trigger: CO2. The switching phenomena of functionalized MWCNTs from hydrophobic to hydrophilic were confirmed using FTIR spectrophotometry and SEM measurements. Under optimized experimental conditions, the enhancement factor (EF) and limit of detection (LOD) were found to be 72 and 0.015 μg L−1, respectively for selenium. Validation of the developed method was carried out by selenium determination using water for trace elements (TM-28.3) as a certified reference material and the results were found to be in good agreement with the certified values. The proposed novel method was then successfully applied for the determination of selenium in real water samples.

Determination of Mercury in Environmental Samples by Using Water Exchangeable Liquid-Liquid Microextraction as Green Extraction Method Couple with Cold Vapor Technique

This is a green method for determination of mercury ion (Hg2+) in environmental samples. The method of exchangeable water based on liquid-liquid microextraction (EW-LLME) was first time introduced as a green analytical separation technique. Exchangeable water was made by the reaction of carbon dioxide with diethylenetriamine. The exchanging phenomena from low polarity to high polarity were confirmed by Fourier transforms infrared spectrometry. The complex formation between Hg2+ and 1, 5-diphenylcarbazone was achieved under the optimized experimental conditions. The enrichment factor and limits of detection of the present method were obtained to be 45.2 and 0.5xa0ngxa0L−1, respectively. The accuracy of the present method was confirmed with certified reference materials. The EW-LLME was successfully applied for determination of Hg2+ in solid matrices of block-III and V of Thar coalfield.

Determination of Arsenic in Water Samples by Using a Green Hydrophobic-Hydrophilic Switchable Liquid-Solid Dispersive Microextraction Method

A simple and green preconcentration method of hydrophobic to hydrophilic switchable liquid-solid dispersive microextraction (HSL-SDM) has been first time introduced as separation method for arsenic ion in real water samples. Multiwall carbon nanotube (MWCNT) was immobilized with diethylenetriamine (DETA) and then used as solid phase adsorbent for the determination of trace level of arsenic ion by HSL-SDM method prior to analysis by hydride generation atomic absorption spectrometry. Reversibly hydrophobic-hydrophilic switchable of functionalized MWCNT can occur due to the exposing of carbon dioxide (CO2) as anti-solvent trigger. The reversibly hydrophobic-hydrophilic switchable phenomena of immobilized MWCNT in the liquid-solid dispersive microextraction were checked by using FT-IR and SEM. The optimized analytical condition for arsenic ion analysis such as enrichment factor and limits of detection were obtained 83 and 3.05xa0ngxa0L−1, respectively. Accuracy of the developed HSL-SDM method was confirmed by the analysis of certified reference materials. Our developed HSL-SDM method was successfully applicable for measurements of arsenic ions in real water samples.

Solid phase extraction of uranium on a new brush type graft copolymer and spectrophotometric determination of its in water samples

A new versatile solid phase extraction and spectrophotometric determination of uranium (VI) was proposed with using poly(caprolactone-b-vinyl benzyl chloride-g-dimethyl amino ethyl methacrylate), poly(CL-b-VB-g-DMAEMA), amphiphilic brush type block/graft copolymer. The method is based on the adsorption of uranium(VI)-pyrocatechol violet complex on surface on the adsorbent. The parameters such as pH, amount of ligand and copolymer, sample volume were optimized. Detection limit, preconcentration factor and relative standard deviation were found as 0.45xa0µgxa0L−1, 100 and 3.8xa0%, respectively. Adsorption capacity of the polymer for uranium(VI) was found 52xa0mgxa0g−1. The method was applied to different water samples and standard reference materials.

Supramolecular solvent microextraction of Sudan blue II in environmental samples prior to its spectrophotometric determination

ABSTRACT A liquid phase microextraction method-based conformation of supramolecular assembly was developed for the separation and preconcentration of trace levels of Sudan blue II. Various analytical parameters such as pH, supramolecular solvent type and volume, sample volume and matrix effect etc. were optimised. Sudan blue II concentration in the extraction phase was determined by UV-visible spectrophotometer. Under the optimised conditions, detection limit and preconcentration factor was found as 2.16 µg L−1 and 80, respectively. Relative standard deviation value was found 5%. The developed procedure was successfully applied for the determination of trace levels of Sudan blue II in environmental samples.