Investigation of use of hydrophilic/hydrophobic NADESs for selective extraction of As(III) and Sb(III) ions in vegetable samples: Air assisted liquid phase microextraction and chemometric optimization.

In this paper, a green, cost-effective sample preparation method based on air assisted liquid phase microextraction (AA-LPME) was developed for the simultaneous extraction of As(III) and Sb(III) ions from vegetable samples using hydrophilic/hydrophobic natural deep eutectic solvents (NADESs). Central composite design was used for the optimization of extraction factors including NADES volume, extraction cycle, pH, and curcumin concentration. Limits of detection for As(III) and Sb(III) were 1.5 ng L-1 and 0.06 ng L-1, respectively. Working ranges for As(III) and Sb(III) were 0.2-300 ng L-1 (coefficient of determination (R2 = 0.9978) and 5-400 ng L-1 (R2 = 0.9996), respectively. Relative standard deviations for As(III) and Sb(III) were 2.2-2.8% and 2.9-3.2%, respectively. Enrichment factor of the method was 184 for As(III) and 172 for Sb(III). The accuracy and precision of the AA-NADES-LPME method were investigated by intraday/interday studies and standard reference material analysis, respectively. Finally, the AA-NADES-LPME method was successfully applied to microwave digested vegetable samples using the standard addition approach and acceptable recoveries were achieved.

Development of a vortex-assisted switchable-hydrophilicity solvent-based liquid phase microextraction for fast and reliable extraction of Zn (II), Fe (II), Pb (II), and Cd (II) from various baby food products.

This manuscript describes the development of a novel liquid phase microextraction (LPME) method for the extraction and determination of Zn (II), Fe (II), Pb (II), and Cd (II) in various infant/baby food and supplements products. The method is based on vortex-assisted extraction combined with a switchable-hydrophilicity solvent (SHS) sample preparation. The SHS, which undergoes reversible phase changes triggered by pH change, enables selective extraction and easy phase separation. A flame atomic absorption spectroscopy was used in the final determination step. Optimization studies revealed, that the optimal pH of the sample solution (after digestion) during analytes extraction is 5.5. A l-proline is added to the sample (375 mM) to ensure the complexation of the target metal cations. After the complexation step, 750 µL of SHS - a N, N-Dimethylcyclohexylamine along with 0.9 mL of 2 M of acetic acid solution is added (hydrophilicity switch-on stage) and mixed manually to obtain a homogeneous solution. In the last stage, 0.45 mL of 10 M NaOH solution (hydrophilicity switch-off stage) is added to the sample solution and a vortex for 100 s is applied to ensure the effective extraction and separation of the complex containing the analytes. At this stage, a cloudy solution is immediately obtained. Finally, the effective phase separation is obtained at the centrifugation step (4000 rpm for 2 mins). The method limit of detection was as 0.03, 0.009, 0.6, and 0.2 ng/L for Zn (II), Fe (II), Cd (II), and Pb (II) respectively with RSD% below 2.0 %. The analysis of certified reference materials and real samples proved the full applicability of the method for routine analysis, contributing to the field of heavy metal analysis and ensuring the safety of baby products. According to the AGREE methodology, this method can be named as green analytical chemistry method with a score of 0.77.

An air-assisted dispersive liquid phase microextraction method based on a hydrophobic magnetic deep eutectic solvent for the extraction and preconcentration of melamine from milk and milk-based products.

In the current research, a fast and sustainable air-assisted hydrophobic magnetic deep eutectic solvent-based dispersive liquid phase microextraction followed by UV-Vis spectrophotometry measurements was optimized for the extraction and determination of melamine in milk and milk-based products. The central composite design was applied for the optimization of factors affecting the recovery of melamine. Quantitative extraction of melamine was achieved using hydrophobic magnetic deep eutectic solvents prepared from a mixture of octanoic acid, aliquat-336, and cobalt(II) chloride. The optimum conditions for extraction were found as follows: 6 extraction cycles, pH 8.2, extraction solvent volume 260 µL, and acetone volume 125 µL.Interestingly, a centrifugation step was not required to achieve phase separation. Under the optimum conditions, melamine was determined in the linear range of 3-600 ng mL-1, the limit of detection (3Sblank/m) of 0.9 ng mL-1, and the enrichment factor of 144. The validation of the method was investigated by the analysis of reference materials. Consequently, the method was successfully applied for the analysis of melamine residues in milk and milk-based products.

Optimization of vortex-assisted switchable hydrophilicity solvent liquid phase microextraction for the selective extraction of vanillin in different matrices prior to spectrophotometric analysis.

The main purpose of this research article is to develop a vortex-assisted switchable hydrophilicity solvent liquid phase microextraction (VA-SHS-LPME) for the selective and efficient extraction of trace vanillin in food samples. Four switchable hydrophilicity solvents (SHSs) were prepared and tested for the extraction of vanillin. The obtained extract phase after phase separation was analyzed by UV-vis spectrophotometry. The extraction parameters including pH, vortex time, NaOH volume, and SHS volume were optimized using central composite design based on response surface methodology. Under optimized conditions, the linear range (0.2-400 ng mL-1 with r2 = 0.9985), limit of detection (0.06 ng mL-1), limit of quantitation (2.0 ng mL-1), extraction recovery (97 ± 4 %) and enhancement factor (220) were obtained. Also, relative standard deviations were less than 2.1 % indicating good precision. The VA-SHS-LPME procedure showed some advantages including good extraction, low consumption of chemical and low matrix effect. Finally, the VA-SHS-LPME procedure was applied for the determination of vanillin in food samples, and acceptable recoveries (91 ± 3-99 ± 3 %) were obtained.

Synthesized of poly(vinyl benzyl dithiocarbonate-dimethyl amino ethyl methacrylate) block copolymer as adsorbent for the vortex-assisted dispersive solid phase microextraction of patulin from apple products and dried fruits.

A new and novel poly(vinyl benzyl dithiocarbonate-dimethyl amino ethyl methacrylate) block copolymer (Pvb-DMA-Xa) as adsorbent was synthesized for the vortex-assisted dispersive solid phase microextraction (VA-DSPME) of patulin from apple products and dried fruits using Uv-visible spectrophotometer. The characterization of synthesized Pvb-DMA-Xa block copolymer was performed with Fourier Transform Infrared spectroscopy (FTIR-ATR) technique. Analytical characteristics such as pH, sorbent amount, adsorption time, eluent type and its volume, desorption time and adsorption capacity were optimized. Limit of detection (3Sb/m) and limit of quantitation (10Sb/m) were found 0.3 and 1.0 ng mL-1. Linear dynamic range (LDR), relative standard deviation (RSD) and recovery values were found in the range of 1-30 ng mL-1, 2.1-2.7 % and 93.5-97.3 %, respectively. Enhancement factor (EF) was found 193. The accuracy of the method was confirmed with standard addition method and analyzing of samples by reference method.

Synthesized of a novel xanthate functionalized polypropylene as adsorbent for dispersive solid phase microextraction of caffeine using orbital shaker in mixed beverage matrices.

A newly synthesized xanthate functionalized chlorinated polypropylene (PP-Xa) was used as adsorbent for the orbital shaker based on dispersive solid phase microextraction (OS-DSPME) of caffein from several tea, coffee, energy drink, coca-cola and chocolate samples using UV-vis. spectrophotometer. Synthesized PP-Xa was characterized using Fourier Transform Infrared spectroscopy (FTIR-ATR) and nuclear magnetic resonance spectroscopy (1H NMR). Various parameters like pH, PP-Xa amount, extraction time, type of eluent and its volume were optimized. Linear range, detection limit (LOD), limit of quantification (LOQ), relative standard deviation (RSD), recovery values, and enrichment factor (EF) were found 90-1000 µgL-1, 27.3 µg L-1, 90 µg L-1, 1.9-2.6%, 98 ± 2%, and 167, respectively. Adsorption capacity of PP-Xa was found 271.9 mg g-1. Standard addition and reference method were used for confirm the accuracy of present method.

Chemometric approach for the spectrophotometric determination of chloramphenicol in various food matrices: Using natural deep eutectic solvents.

A novel, simple and green temperature controlled-natural deep eutectic solvent emulsification liquid-liquid microextraction (TC-NADES-LLME) coupled with UV-vis spectrophotometry was optimized for preconcentration and measurement of chloramphenicol (CAP) in eggs, milks honeys and chicken meat. Four different NADES were prepared and investigated for the efficient extraction of CAP. The important parameters (pH, NADES-3 vol, Fe(III) amount and extraction temperature) affecting the extraction efficiency of the TC-NADES-LLME procedure were investigated and optimized using a chemometric approach. In this study, Fe(III), NADES-3 and extraction temperature were used as complexing agent, extraction solvent and emulator accelerator, respectively. Using optimized values, the linear range of the TC-NADES-LLME procedure was in the range of 0.1-300 µg L-1 with a coefficient of determination of 0.9991. The detection limit and enhancement factor were 0.03 µg L-1 and 285, respectively. The precision of the method has been confirmed in repeatability and reproducibility studies. Relative standard deviation of these studieswas<4.2 %. The matrix effect was investigated by adding three different CAP concentrations to the selected samples, and the results indicated the low matrix effect of the method. The TC-NADES-LLME procedure was successfully applied to determine and extract CAP in the selected samples.

Experimental design of ligandless sonication-assisted liquid- phases microextraction based on hydrophobic deep eutectic solvents for accurate determination of Pb(II) and Cd(II) from waters and food samples at trace levels.

A straightforward, accurate and efficient analytical procedure was developed by ligandless sonication-assisted liquid- phases microextraction based on hydrophobic deep eutectic solvents (SA-LPME-HDES) to trace toxic Pb(II) and Cd(II) in waters and foods. Optimization of the SA-LPME-HDES procedure was carried out by Box-Behnken design. Under optimum conditions, linear ranges for Pb(II) and Cd(II) were 0.8-350 (r2:0.9962) and 1.5-500 µg L-1 (r2: 0.9937), respectively. Relative standard deviations (N = 5, 10 µg L-1) were 1.4% for Pb(II) and 1.6% for Cd(II), respectively. Limits of detection were 0.24, and 0.46 µg L-1, respectively. The accuracy was evaluated by the analysis of two certified reference materials and the results were to be in agreement with the certified values. The SA-LPME-HDES method was successfully applied to tap water, mineral water, river water, well-water, sesame, peanut, eggplant, corn, wheat, soy and cucumber. The SA-LPME-HDES method allows operational simplicity, green, and low cost when compared with some microextraction procedure.

A new analytical approach for preconcentration, separation and determination of Pb(II) and Cd(II) in real samples using a new adsorbent: Synthesis, characterization and application.

A green and efficient analytical approach was reported for simultaneous preconcentration, and separation of Pb(II) and Cd(II) in water, vegetables, and barbecue samples by dispersive solid-phase microextraction prior to their determination using flame atomic absorption spectrometry. A new poly-3-hydroxy butyrate-polyvinyl triethyl ammonium chloride comb-type amphiphilic cationic block copolymer (PHBvbNCl) was synthesized and characterized. Main variables such as pH, sorbent amount, adsorption time, eluent type, desorption time, and sample volume were optimized. Detection limits and working ranges for Pb(II) and Cd(II) were 0.03 µg L-1, 0.15 µg L-1, 0.1-250 µg L-1 and 0.5-375 µg L-1, respectively. Enhancement factor for Pb (II) and Cd (II) were 114 and 98. The adsorption capacity of PHBvbNCl for Pb(II) and Cd(II) was 175.2 mg g-1 and 152.9 mg g-1. After the accuracy of the method was confirmed by the analysis of certified reference materials, it was successfully applied to real samples. Finally, the analytical performance of the present method was compared with other methods.

Optimization of green and rapid analytical procedure for the extraction of patulin in fruit juice and dried fruit samples by air-assisted natural deep eutectic solvent-based solidified homogeneous liquid phase microextraction using experimental design and computational chemistry approach.

In this paper, a green and inexpensive air-assisted natural deep eutectic solvent-based solidified homogeneous liquid phase microextraction procedure was optimized for extraction of patulin in fruit juice and dried fruit samples using experimental design prior to its spectrophotometric determination. Four different natural deep eutectic solvent were prepared and applied to ensure efficient, and selective extraction of patulin. The significant variables including Zn(II) amount, cooling time, pH and amount of natural deep eutectic solvent were optimized by using central composite design. Under optimized conditions, working range was 10-750 µg L-1 with 0.9996 of correlation coefficient. Detection limit and preconcentration factor were 3.5 µg L-1 and 150, respectively. The repeatability and reproducibility precision were in the range of 3.2-4.6% and 4.3-5.6% respectively. Recoveries ranging from 94% to 104% proved the accuracy of the method. The optimized method was successfully applied to the extraction and identification of patulin in the selected samples.

Development of sensitive and accurate solid-phase microextraction procedure for preconcentration of As(III) ions in real samples.

We synthesized the poly(methyl methacrylate-co-2-aminoethyl methacrylate (PMaema) amphiphilic copolymer in a form of solid phase adsorbent. Then it was used for separation, preconcentration and determination of trace amount of As(III) ions from foods and waters with hydride generation atomic absorption spectrometry. The PMaema was characterized by fourier transform infrared spectrometer and nuclear magnetic resonance spectrometer. The adsorption of As(III) to the PMaema was also supported using computational chemistry studies. The experimental parameters (pH, PMaema amount, adsorption time and ethanol volume) were optimized using a three-level Box-Behnken design with four experimental factors. We observed linear calibration curve for the PMaema amount in the 10-500 ng L-1 range (R2 = 0.9956). Limit of detection, preconcentration factor and sorbent capacity of PMaema were equal to 3.3 ng L-1, 100 and 75.8 mg g-1, respectively. The average recoveries (spiked at 50 ng L-1) changes in the range of 91.5-98.6% with acceptable relative standard deviation less than 4.3%. After validation studies, the method was successfully applied for separation, preconcentration and determination of trace amount of As(III) from foods and waters.

Optimization of an ultrasound-assisted alcohol-based deep eutectic solvent dispersive liquid-phase microextraction for separation and preconcentration of quercetin in wine and food samples with response surface methodology.

We optimized ultrasound-assisted alcohol-based deep eutectic solvent dispersive liquid-phase microextraction for separation and preconcentration of quercetin in wine and food samples by experimental design based on central composite design. Five different alcohol-based deep eutectic solvents were prepared and tested for quercetin extraction. The effect of important parameters and matrix components were optimized. After optimization, the determination of quercetin was performed at 385 nm using spectrophotometry. Analytical data such as detection limit, working range and preconcentration factor were found as 6.1 µg/L, 20-850 µg/L, and 120, respectively. The selectivity of the optimized extraction conditions for quercetin was investigated in the presence of different matrices. The validation of the method was investigated by reproducibility, repeatability and recovery studies, as well as by comparing the analytical results obtained from real samples with the reference method. Lastly, the recommended procedure was successfully applied for the extraction and quantification of quercetin in wine and food samples.

Ultrasonic-assisted cloud point microextraction and spectrophotometric determination of Ponceau 4R in various beverage samples using Non-ionic surfactant PONPE 7.5.

In the current study, a simple, cheap, and fast analytical procedure, termed ultrasonic-assisted cloud point microextraction (UA-CPME), combined with UV-VIS spectrophotometry, was developed for the pre-concentration and identification of Ponceau 4R in some beverage samples. Ponceau 4R was extracted from aqueous solution using polyethylene glycol mono-p-nonylphenyl ether (PONPE 7.5) as extraction solvent in the presence of Cu(II) at pH 6.0. Variables influencing the UA-CPME extraction efficiency such as pH, metal type and amount, temperature, ultrasonic effect, solvent type, non-ionic surfactant type and concentration were optimised in detail. Under optimum conditions, the analytical properties of the developed method were as follows: linear working range, 20-750 µg L-1; limit of detection, 6.5 µg L-1; and the pre-concentration factor, 200. The relative standard deviation (RSD%) obtained for 50 µg L-1 (n = 5) of Ponceau 4R was 2.9%. The accuracy and precision of the method were evaluated by intra-day and inter-day studies. Finally, the developed method has been successfully applied to the separation and identification of Ponceau 4R in the selected samples and the recoveries ranged from 94.3 to 104.2.

Ionic hydrophobic deep eutectic solvents in developing air-assisted liquid-phase microextraction based on experimental design: Application to flame atomic absorption spectrometry determination of cobalt in liquid and solid samples.

This paper reports a new and simple microextraction procedure for cobalt determination using green ionic hydrophobic deep eutectic solvent in developing air-assisted liquid-phase microextraction and flame atomic absorption spectrometry. Thecomplexationof Co(II) ions was carried out by using dithizone solution as complexing agent at pH5.The key variables affecting microextraction steps were optimized by response surface methodology (RSM) based on central composite design. Under the optimum microextraction conditions, calibration graph was linear in the range of 0.1-500 µg L-1 Co(II) with correlation coefficient of 0.9985. Additionally, detection limit, quantitation limit and enrichment factor were found to be 0.04 µg L-1, 0.1 µg L-1 and 175, respectively. The reproducibility and repeatability were ≤ 2.9% and ≤ 3.6%, respectively. Based on the results obtained, the proposed methodology has been successfully employed for Co analysis in liquid and solid samples with recovery range of 94.2-105%.

Poly(styrene)-co-2-vinylpyridine copolymer as a novel solid-phase adsorbent for determination of manganese and zinc in foods and vegetables by FAAS.

The aim of this study is to extract zinc and manganese from foods and vegetables using an amphiphilic copolymer adsorbent, poly(styrene)-co-2-vinylpyridine which was synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization from styrene and 2-vinyl pyridine in the presence of a trithiocarbonate and 2,2'-azo-bis isobutyro nitrile (AIBN) in toluene solution under argon at 80 °C. Fourier Transform Infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy were used in the characterization of the obtained copolymer. Under the optimum conditions, several validation variables such as uncertainty measurement, selectivity, robustness, precisions, matrix effects and accuracy were investigated. Taking an adsorption time of 15 min, detection limits of 0.04 µg L -1 and 0.2 µg L-1and 7.9 µg L-1and enrichment factors of 145 and 110 were obtained for Mn(II) and Zn(II), respectively.The method was successfully applied to the analysis of Mn(II) and Zn(II) in foods and vegetables.

A green and efficient vortex-assisted liquid-phase microextraction based on supramolecular solvent for UV-VIS determination of nitrite in processed meat and chicken products.

This paper describes a simple, efficient and rapid analytical method for extraction and determination of nitrite in meat and chicken products by vortex-assisted supramolecular solvent-based liquid phase microextraction (VA-SUPRAS-LPME) prior to spectrophotometric detection. The SUPRAS was rapidly formed by the addition of a colloidal decanoic acid suspension to tetrahydrofuran (THF). The validation studies were carried out in terms of linearity, limit of detection (LOD), limit of quantitation (LOQ), matrix effects, robustness, uncertainty measurement, precision, accuracy, and certified reference material (CRM) analysis using optimized experimental conditions. The LOD, LOQ, linearity and matrix effect were 0.035 ng mL-1, 0.1 ng mL-1, 0.1-300 ng mL-1, and 9.6% respectively, with high preconcentration factor (200). The method was successfully applied for the determination of nitrite in processed products. Moreover, the results obtained by the proposed method were compared to the standard Griess method, and showed no significant differences in term of Student's t-test.

A simple and quick ionic liquid-based ultrasonic-assisted microextraction for determination of melamine residues in dairy products: Theoretical and experimental approaches.

In this study, a simple and quick ionic liquid- based ultrasonic-assisted microextraction (IL-UA-ME) procedure has been improved for extraction of melamine in dairy productsfollowed by UV-VIS spectrometry. For the analysis of stability and reactivity of melamine and its some metal complexes, quantum chemical parameters like frontier orbital energy-HOMO-LUMO energy gap, hardness and softness were calculated using computational chemistry tools. The results regarding to stability analysis made considering density functional theory showed that theoretical data obtained are compatible with experimentally obtained results, and Fe-melamine complex is more stable compared to others. Under optimum conditions, the linearity was in the range of 0.05-400 ng mL-1 with detection limit of 0.015 ng mL-1. Following the validation studies, recovery and relative standard deviation were obtained in range of 92.5-104.3% and 1.4-2.1%, respectively. The first research article in which experimental and theoretical studies are used together for the determination of melamine in dairy products.

Alcohol-DES based vortex assisted homogenous liquid-liquid microextraction approach for the determination of total selenium in food samples by hydride generation AAS: Insights from theoretical and experimental studies.

This research article proposes a simple, quick, green and cheap approach for the determination of total selenium in food samples using alcohol-DES based vortex-assisted homogenous liquid-liquid microextraction (alcohol-DES-VA-HLLME) combination with hydride generation atomic absorption spectrometry (HG AAS). Analyte, complexing agent and working pH were Se(IV), Sudan-II and pH 4.0, respectively. In order to analyze the nature of the chemical interaction between Se(IV) ion and Sudan-II ligand, experimental results were supported with computational chemistry tools calculating quantum chemical descriptors like frontier orbital energies, hardness, softness, electronegativity, electrophilicity, nucleophilicity, transferred electron from the ligand to ion, electron donating power, electron accepting power, complexation energy, molecule-ion interaction energy. In addition, the alcohol-DES-VA-HLLME method was earned a good detection limit of 3.5 ng L-1 and a wide calibration curve in the concentration range of 12-300 ng L-1 (r: 0.9981). The validity of the method was evaluated by analyzing the two standard reference material (SRMs). The recoveries and relative standard deviations for 25 and 100 ng L-1 of Se(IV) (N:5) were in the range of 1.2-2.5% and 92.1-103.7% respectively, which proved acceptable. The analytical results showed that the proposed method had important features such as cheapness, green, quick extraction and reuse, which made it attractive for the determination and efficient extraction of total selenium in the food samples.

Towards green analysis of curcumin from tea, honey and spices: Extraction by deep eutectic solvent assisted emulsification liquid-liquid microextraction method based on response surface design.

A fast, cheap and green analytical method was developed for the determination and extraction of curcumin in tea, honey, and spices using deep eutectic solvent-assisted emulsification liquid-liquid micro-extraction (DES-ELLME) coupled to UV-VIS spectrophotometry. Quantitative extraction of curcumin from the sample was obtained by the DES, which was prepared by mixing choline chloride and maltose in a 1:3 molar ratio. Response surface design was used for the optimisation of significant experimental parameters including sample pH, amount of extraction solvent, amount of emulsifier solvent and vortex time. The optimum conditions obtained were pH 4.25, 762.5 µL of DES, 107.5 mL of tetrahydrofuran and 3.4 min vortex time, while keeping centrifugation speed fixed at 4000 rpm, 5 min. Under the extraction conditions obtained, analytical features such as calibration equation, limit of detection, enrichment factor, and linearity were Abs = 6.5 × 10-4 [Curcumin, ng mL-1]-1.2 × 10-5, 0.1 ng mL-1, 114 and 0.4-120 ng mL-1, respectively. Moreover, the repeatability and reproducibility of the DES-ELLME method, expressed as relative standard deviation (RSDs%), varied in the ranges of 1.4-3.0% and 2.0-4.3%, respectively. Finally, the proposed method was successfully applied to the extraction and determination of curcumin from prepared samples. The relative mean recovery ranged from 92.3% to 104.4%.

Usage of the newly synthesized poly(3-hydroxy butyrate)-b-poly(vinyl benzyl xanthate) block copolymer for vortex-assisted solid-phase microextraction of cobalt (II) and nickel (II) in canned foodstuffs.

The current research article was reported the synthesis of a novel poly(3-hydroxy butyrate)-b-poly(vinyl benzyl xanthate) block copolymer (PHB-Xa) for vortex-assisted solid-phase microextraction of cobalt(II) and nickel(II) from canned foodstuffs prior to their determinations by flame atomic absorption spectrometry. The block copolymer was synthesized and characterized by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. Experimental variables affecting the extraction efficiency of the copolymer were optimized. Since the PHB-Xa block copolymers have a high π conjugate structure and hydrophobicity, the use of this adsorbent yielded quantitative results for the extraction of Ni(II) and Co(II). After optimization, the linearities for Ni(II) and Co(II) were 0.05-80 ng mL-1 and 0.2-100 ng mL-1, respectively. The limits of detection and the limits of quantification were in the range of 0.015-0.06 ng mL-1 and 0.05-0.2 ng mL-1, respectively. The method was successfully applied to determination of Ni(II) and Co(II) in canned foodstuffs prepared by microwave digestion.