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 (3S_blank/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.

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.

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%.

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.

Analysis of Zinc and Chromium in Grain Samples Using Ionic Liquid-Based Ultrasound-Assisted Microextraction Followed by Flame-AAS After Microwave Digestion

A simple, rapid and eco-friendly microextraction method was developed for the determination and preconcentration of zinc (Zn) and chromium (Cr) from grain products by ultrasonic-assisted ionic liquid dispersive liquid-liquid microextraction (UA-IL-DLLME) combined with flame atomic absorption spectrometry (FAAS). Quercetin (2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one dihydrate) was used for the complexation of Zn(II) and Cr(III) ions at different pHs. The 1-hexyl-3-methylimidazolium bis[(trifluoromethyl) sulfonyl]imide ([Hmim][NTf2] and acetonitrile were used as extraction solvent and dispersive solvent, respectively. To provide quantitative extraction of analytes, important experimental variables such as pH of sample solution, temperature, ultrasonic time, amount of chelating agent, amount of ionic liquid, type and amount of dispersive solvent, and interference effect were extensively studied and optimized. The detection limits and operating ranges for Zn(II) and Cr(III) using the optimized conditions were 7.5, 25-450 and 2.4, 8-300 μg L^-1, respectively. For the validation of the proposed method, the certified reference material was tested using the standard addition method. After microwave digestion analysis of grain products, relative standard deviations (RSDs%) and recoveries were ranged from 1.2 to 2.3% and from 91.2 to 103.7%, respectively. The UA-IL-DLLME method has been successfully applied for the determination of Zn and Cr in grain samples (chickpea, broad bean, pea, beans, and wheat).

Simple and Green Heat-Induced Deep Eutectic Solvent Microextraction for Determination of Lead and Cadmium in Vegetable Samples by Flame Atomic Absorption Spectrometry: a Multivariate Study

In this study, a simple, green, and cheap analytical procedure based on heat-induced deep eutectic solvent microextraction (HI-DES-ME) coupled with flame atomic absorption spectrometer (FAAS) was developed for the determination of Pb(II) and Cd(II) in vegetables. After the preliminary experiment, response surface methodology (RMS) based on central composite design (CCD) was used for the optimization of critical factors such as pH of sample solution, amount of extraction solvent, temperature, and amount of ligand. Microwave step was applied for the digestion of vegetable samples. Under optimum conditions obtained by the CCD, calibration graphs for Pb(II) and Cd(II) were linear in the concentration range of 0.5-250 and 1.0-300 ng mL^-1, respectively. Limits of detection (LODs) and sensitivity enhancement factor (SIFs) were found in the range of 0.17-0.35 ng mL^-1 and 93-67 ng mL^-1, respectively. Relative standard deviations (N = 10, RSDs%) for Pb(II) (10 ng mL^-1) and Cd(II) (50 ng mL^-1) were 3.7% and 2.3%, respectively. In order to validate the proposed method, certified reference material (CRM) and spiked samples were used. Experimental results showed that there was no significant difference between the obtained and certified values. Then, the proposed method was successfully applied for the preconcentration and determination of Pb(II) and Cd(II) in different vegetables.

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.

Vortex assisted-ionic liquid dispersive liquid-liquid microextraction and spectrophotometric determination of quercetin in tea, honey, fruit juice and wine samples after optimization based on response surface methodology

The aim of our study is to develop a new vortex assisted-ionic liquid dispersive liquid-liquid microextraction (VA-IL-DLLM) method for preconcentration and determination of the quercetin in tea, honey, fruit juice and wine samples by spectrophotometry. The method is based on pH sensitive ion-pair formation between quercetin and rhodamine B at pH 6.5 by donor-acceptor mechanism, and then dispersion of the complex in the fine-drops of ionic liquid (IL). In this context, the effects of pH, concentrations of ion-pairing reagent, the IL, vortex time and dispersive solvent type on the preconcentration process of quercetin were investigated using a 2-level-5-factor central composite half fraction design (CCD) as experimental design for response surface methodology (RSM). Quantitative model was developed to determine the quercetin in food samples, and it is verified by analysis of variance (ANOVA) at a 95% confidence level (P < 0.05). Response surface plots and contour plots obtained by the model are used to determine the interactions of experimental variables. After the optimization, calibration graph was obtained between 35 and 750 μg L^-1 with the detection limit of 10.2 μg L^-1. The recovery and relative standard deviations (RSD%) were in range of 94-104%, and in range of 2.5-4.2%, respectively. The accuracy and precision of the method were tested by the experimental studies such as recoveries, intermediate precision, trueness and expanded uncertainty. A comparison of the current results to those reported for other studies is also presented.

Inactivation of Staphylococcus aureus and Escherichia coli O157:H7 on fresh kashar cheese with pulsed ultraviolet light

Pulsed ultraviolet light is a potential postprocessing decontamination method which is able to reduce pathogens on solid food surfaces. Cheese surfaces may become easily contaminated with pathogens due to improper handling or contact with unhygienic surfaces during or after processing. In this study, the effects of pulsed ultraviolet light on Staphylococcus aureus and Escherichia coli O157:H7 on fresh kashar cheese were investigated. Pulsed ultraviolet light was applied to kashar cheese for different times (5, 15, 30, 45, 60 s) at 5, 8, and 13 cm from the quartz window in a pulsed ultraviolet light system. Based on the inactivation level, time, and visual evaluation, the most favorable treatment was determined as the 45 s-13 cm treatment (∼44 J/cm²). This treatment yielded about 1.62 and 3.02 log₁₀ reductions (cfu/cm²) for S. aureus and E. coli O157:H7, respectively, while did not alter (p>0.05) the pH, lipid oxidation, and moisture content of kashar cheese, except the color parameters. When 0.5 cm thick kashar cheese was treated with pulsed ultraviolet light at a distance of 5 cm from the quartz window, the highest energy transmittance was found to be about 9.16%. These findings demonstrate that pulsed ultraviolet light has the potential for postprocessing decontamination of semi-hard cheese surfaces.

Innovative and practical deep eutectic solvent based vortex assisted microextraction procedure for separation and preconcentration of low levels of arsenic and antimony from sample matrix prior to analysis by hydride generation-atomic absorption spectrometry

Considering the negative impacts on human health and the environment, determinations of arsenic (As) and antimony (Sb), is of unquestionable importance. The present study describes the development of innovative and practical deep eutectic solvent (DES) based vortex assisted microextraction (DES-VAME) method for preconcentration of As and Sb from environmental waters, honey and rice prior to analysis by hydride generation-atomic absorption spectrometry (HG-AAS). The use of As(III) and Sb(III) in presence of dithizone at pH 10.5 by means of donor-acceptor mechanism were decided as analytes. Total As and Sb were determined after reduction process. The analytical properties obtained following optimization were as follows. Limit of detection (LOD), precision (as RSD%), recoveries and enhancement factor for As and Sb were calculated as 7.5 ng L^-1/15.6 ng L^-1, 2.1% /2.7%, 93.5%/96.2% and 104/85, respectively. Following validation with certified reference material, the method was successfully applied to the analysis of real samples.