Development of an orbital shaker-assisted fatty acid-based switchable solvent microextraction procedure for rapid and green extraction of amoxicillin from complex matrices: Central composite design.

In this study, a cheap, fast and simple orbital shaker-assisted fatty acid-based switchable solvent microextraction (OS-FASS-ME) procedure was developed for the extraction of amoxicillin (AMOX) in dairy products, pharmaceutical samples and wastewater prior to its spectrophotometric analysis. Fatty acid-based switchable solvents were investigated for extracting AMOX. The key factors of the OS-FASS-ME procedure were optimized using a central composite design. The linearity of OS-FASS-ME procedure was in the range 5-600 ng mL-1 with a correlation coefficient of 0.991. In five replicate experiments for 20 ng mL-1 of AMOX solution, the recovery and relative standard deviation were 95.8% and 2.2%, respectively. Limits of detection and quantification were found 1.5 ng mL-1 and 5 ng mL-1, respectively. The accuracy, precision, robustness and selectivity of the OS-FASS-ME procedure were investigated in detail under optimum conditions. The OS-FASS-ME procedure was applied to milk, cheese, wastewater, syrups and tablets. A comparison of the results obtained from the reference method and the OS-FASS-ME method showed that the OS-FASS-ME procedure can be successfully applied to complex matrices.

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.

Optimization of [P6,6,6,14+]3[GdCl63-] magnetic ionic liquid assisted dispersive liquid-liquid microextraction for selective and sensitive determination of cadmium in environmental water and food.

A simple and green hydrophobic magnetic ionic-liquid assisted dispersive liquid-liquid microextraction (MIL-DLLME) was optimized for the determination of trace cadmium (Cd (II)) in environmental and food samples by flame atomic absorption spectrophotometer. To achieve selective and sensitive extraction of Cd (II), four MILs were prepared and tested. Extraction parameters of the MIL-DLLME including pH, type and volume of the MIL, type and volume of dispersive solvent, extraction cycle, ionic strength and sample volume were investigated in detail and optimized by Box-Behnken design. Under optimum conditions, matrix effect, recovery study, intra-day and inter-day precision were performed for the MIL-DLLM. The analytical characteristics such as limit of detection, limit of quantification and pre-concentration factor were 0.17, 0.56 and 125 ng mL-1, respectively. The validation of the MIL-DLLME was evaluated by analysis of reference materials. Moreover, the accuracy of the results in the analysis of real samples was evaluated by standard addition and quantitative recoveries (91 ± 5-101 ± 2%) were achieved. The results obtained in the analysis of both reference materials and real samples showed that the MIL-DLLME has a selective applicability for cadmium.

Ultra-Sensitive Determination of Cadmium in Food and Water by Flame-AAS after a New Polyvinyl Benzyl Xanthate as an Adsorbent Based Vortex Assisted Dispersive Solid-Phase Microextraction: Multivariate Optimization.

Background: Cadmium (Cd) is a very toxic and carcinogenic heavy metal even at low levels and it is naturally present in water as well as in food. Methods: A new polyvinyl benzyl xanthate (PvbXa) was synthesized and used as a new adsorbent in this work. It contains pendant sulfide groups on the main polystyryl chain. Using this new adsorbent, PvbXa, a vortex-assisted dispersive solid-phase microextraction (VA-dSPµE) procedure was developed for the determination of cadmium from food and water samples via flame atomic absorption spectrophotometry (FAAS). Synthesized PvbXa was characterized by 1H Nuclear magnetic resonance (NMR) Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). The different parameters of pH, sample volume, mixing type and time, sorbent amount, and eluent time were optimized using standard analytical methods. Results: The optimized method for assessment of Cd in food and water samples shows good reliability. The optimum conditions were found to be a 0.20-150 µg L-1 linear range, 0.06 µg L-1 LOD, 0.20 µg L-1 LOQ, 4.3 RSD %, and a preconcentration factor of 160. Conclusions: The statistically experimental variables were utilized using a central composite design (CCD). The present method is a low-cost, simple, sensitive, and very effective tool for the recovery of Cd.

Ultrasound assisted dispersive solid phase microextraction using polystyrene-polyoleic acid graft copolymer for determination of Sb(III) in various bottled beverages by HGAAS.

A new polyoleic acid-polystyrene (PoleS) block/graft copolymer was synthesized and applied as adsorbent for ultrasound assisted dispersive solid phase microextraction (UA-DSPME) of Sb(III) in different bottled beverages and analysis using hydride generation atomic absorption spectrometry (HGAAS). Adsorption capacity of the PoleS was 150 mg g-1. Several sample preparation parameters such as sorbent amount, solvent type, pH, sample volume and shaking time were optimized (based on central composite design (CCD) approach) and evaluated in respect to the recovery of Sb(III). The method revealed a high tolerance limit of matrix ions presence. Under optimized conditions, linearity range, the limit of detection, the limit of quantitation, extraction recovery, enhancement factor, preconcentration factor were 5-800 ng L-1, 1.5 ng L-1, 5.0 ng L-1, 96%, 82, 90, respectively. Accuracy of the UA-DSPME method was confirmed based on different certified reference materials and standard addition method. Factorial design was utilized to estimate the influences of variables of recovery of Sb(III).

Optimization of vortex-assisted hydrophobic magnetic deep eutectic solvent-based dispersive liquid phase microextraction for quantification of niclosamide in real samples.

In this manuscript, a green and fast vortex-assisted hydrophobic magnetic deep eutectic solvent-based dispersive liquid phase microextraction (VA-HMDES-DLPME) method was developed for the selective extraction and determination of niclosamide in read samples, including rice, medicine tablets, and water samples. Here, hydrophobic magnetic deep eutectic solvents were used as the extracting solvent without requiring any centrifugation step. In the light of preliminary experiments, important parameters, such as volume of extraction solvent, pH, acetonitrile volume and vortex time, affecting the extraction efficiency of niclosamide were optimized using a Box-Behnken design. The linear dynamic range (0.25-120 µg/L), the limit of detection (0.08 µg/L), the limit of quantitation (0.25 µg/L), preconcentration factor (180), and enrichment factor (130) of the method were determined using optimized data. In particular, the validation parameters of the optimized VA-HMDES-DLPME, including robustness, matrix effect accuracy, and precision, were investigated. In addition to this, intra- and inter-day precisions were determined as ≤3.5 % and ≤4.1%, respectively. Finally, the optimized method was successfully used for the extraction of niclosamide in the selected samples prior to spectrophotometric analysis.

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.

Preparation of fatty acid-based ternary deep eutectic solvents: Application for determination of tetracycline residue in water, honey and milk samples by using vortex-assisted microextraction.

Simple, rapid, low cost, selective, and sensitive analytical method was developed using fatty acid-based ternary deep eutectic solvents (TDESs) for extraction and determination of tetracycline in honey, milk and water samples by vortex assisted (VA) microextraction and UV-vis spectrophotometer. Four different TDES were prepared by combination of nonanoic acid, dodecanoic acid, decanoic, hexanoic acid, octanoic acid. Analytical parameters such as pH, TDES types and its molar ratio, dispersive solvent types and solvent volume and salt effect were optimized. VA-TDES method was good recovery of tetracycline in the samples from 94 to 99%. The LOD and LOQ values were found 1.0 and 3.3 µg L-1, respectively. The linear range of calibration graph was 3.3 -450 µg L-1. Intra-day and inter-day precision was found 2.8-4.1% and 3.6-5.2%. Enhancement factor was found 109. The factorial design was drawn to evaluate the significant level of factors and effects of variables on the recovery of tetracycline. Standard addition method was used for the validation and accuracy of the method. Present VA-TDES method was successfully applied to real samples.

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.

Ultrasonic-assisted dispersive liquid-liquid microextraction based on hydrophilic deep eutectic solvents: Application to lead and cadmium monitoring in water and food samples.

A green and innovative ultrasonic-assisted dispersive liquid-liquid microextraction using hydrophilic deep eutectic solvents (UA-HDES-DLLME) was developed for the selective and simultaneous extraction and enrichment of Pb (II) and Cd (II) in water and food samples for flame atomic absorption spectrometry. Several natural deep eutectic solvents (NADES) were used for the preparation of six different HDES and methyl violet was used as chelating reagent. Effective parameters such as pH, sonication time, methyl violet amount, DES type, dispersive solvent types, etc were optimized. Relative standard deviation (RSD) and preconcentration factor (PF) were 4.0% and 80. Low limits of detection (LOD, 1.3 ng mL-1 for Pb (II) and 0.33 ng mL-1 for Cd (II)) and quantification (LOQ, 4.0 ng mL-1 for Pb (II) and 1.0 ng mL-1 for Cd (II)) were found. The method accuracy was confirmed with analyses of certified reference materials.

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.

Chemometric design-based optimization of a green, selective and inexpensive switchable hydrophilicity solvent-based liquid phase microextraction procedure for pre-concentration and extraction of sulfadiazine in milk, honey and water samples.

In this research, a green, selective and inexpensive switchable hydrophilicity solvent-based liquid phase microextraction (SHS-LPME) procedure has been optimized for the extraction and preconcentration of sulfadiazine (SDZ) in milk, honey and water samples prior to spectrophotometric analysis. Five variables affecting the SHS-LPME procedure were optimized using chemometric-based central composite design. For the SHS-LPME procedure, analytical parameters such as linearity, limit of detection, extraction recovery and enrichment factor were 15-300 µg L-1, 4.5 µg L-1, 96 ± 3% and 113, respectively. The precision of the method was investigated by repeatability and reproducibility studies. The relative standard deviation from these studies was found in the range of 2.4-4.5%. The recovery of the SDZ in the samples was in the range of 94 ± 4-99 ± 2%. Collected samples were analyzed by both the SHS-LPME procedure and the reference method using flow injection-flame atomic absorption technique, and the results were compared. There was no statistically significant difference between the two methods. This showed that the SHS-LPME procedure can be safely applied to the analysis of real samples.

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.

In-situ sorbent formation for the extraction of pesticides from honey.

An organic polymer was re-precipitated in solution to use as an adsorbent in dispersive solid-phase extraction of some pesticides from honey samples prior to their determination by high-performance liquid chromatography-tandem mass spectrometry. In this approach, different deep eutectic solvents were prepared using lysine and their ability in elution of the analytes from the adsorbent surface was tested. A diluted honey solution was transferred into a glass test tube and then a solution of polystyrene dissolved in dimethylformamide was injected into the solution. By doing this, polystyrene is re-precipitated in the solution and dispersed in whole parts of it as many tiny particles. Then the mixture was centrifuged and the adsorbed analytes on the particles were eluted using a proper hydrophilic deep eutectic solvent. The central composite design approach was used for the optimization of effective parameters. The limits of detection and quantification were in the ranges of 0.06-0.20 and 0.22-0.69 ng/g, respectively. The calibration curves obtained by matrix-matched standard solutions were linear in the range of 0.69-500 ng/g with a coefficient of determinations ≥0.9962. The method provided high extraction recoveries (70-99%) and enrichment factors (140-198), and an acceptable precision (relative standard deviations ≤7.1%).

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.

Air-Assisted Alkanol-Based Nanostructured Supramolecular Liquid-Liquid Microextraction for Extraction and Spectrophotometric Determination of Morin in Fruit and Beverage Samples.

A new air-assisted liquid-liquid microextraction method based on alkanol nanostructured supramolecular solvents coupled to spectrometric analysis was developed for extraction, preconcentration, and spectrophotometric determination of morin. Al(III)-morin complex was performed at pH 4.5. Four different alkanol-based SUPRAS (supramolecular solvents) were prepared for the separation and preconcentration of Al-morin complex from aqueous solution by using vortex and centrifugation. Effect of analytical variables and tolerance limit of matrix ions were investigated. Under the optimum conditions, detection limit, quantification limit, relative standard deviation, preconcentration factor, and enhancement factor were found as 3.5 µg L-1, 10 µg L-1, 3.1%, 120, and 95, respectively. The accuracy of the method was performed with standard addition. The obtained results demonstrated the applicability of the method for the separation, preconcentration, and determination of morin in fruit and beverage samples. The method also complies with green chemistry principles as it uses green solvents, reduces reagent volumes, and produces low amounts of waste. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12161-021-02111-3.

Synthesis of polystyrene-polyricinoleic acid copolymer containing silver nano particles for dispersive solid phase microextraction of molybdenum in water and food samples.

Polystyrene-polyricinoleic acid copolymer containing silver nano particles (AgPSrici) was synthesized and used in separation of molybdenum from different aqueous and foodstuff samples during a dispersive-µ-solid phase extraction approach. The synthesized nano particles were verified using Fourier transform infraredspectroscopy. An electrothermal atomic absorption spectrometry has been used for measurement of the studied ions. AgPSrici amount pH, sample volume, elution solvent kind, and the time of extraction were the effective parameters that were optimized by one-variable-at-one-time method. Analytical data of the method was calculated and limit of detection, relative standard deviation, limit of quantification were 0.022 µg L-1, 2.9%, 150, and 0.066 µg L-1, respectively. The synthesized adsorption capacity was obtained 170 mg g-1.Accuracy of the method was studied by performing the method on certified reference materials and the presence of different interfering ions was studied. Molybdenum content of different water and foodstuffs was determined by the introduced method.

Air-assisted liquid-liquid microextraction of total 3-monochloropropane-1,2-diol from refined edible oils based on a natural deep eutectic solvent and its determination by gas chromatography-mass spectrometry.

In this paper, a fast, sensitive, and selective sample preparation procedure was presented for the determination of 3-monochloropropane-1,2-diol (3-MCPD) in refined edible oils using gas chromatography-mass spectrometry. In this method, firstly, the sample lipids and analyte fatty esters are saponified by sodium hydroxide under sonication. After that the analyte was derivatized using phenylboronic acid (as the derivatization agent) and the obtained derivative was extracted during an air-assisted liquid-liquid microextraction procedure (AALLME). Six different deep eutectic solvents (DESs) were prepared as the extraction solvents and the most effective extraction for 3-MCPD was obtained in the presence of a natural DES (NDES) consisting of choline chloride (ChCl)-acetic acid (AcOH). Important variables such as sodium hydroxide concentration and volume, sonication time, temperature, extraction solvent type and volume, and phenylboronic acid concentration and volume have been optimized. Using the optimum conditions, broad linear range (0.88-1000 ng g-1), suitable coefficient of determination (0.995), and low limits of detection (0.26 ng g-1) and quantification (0.88 ng g-1) were obtained. Relative standard deviations for intra- (n=8) and inter-day (n=6) precisions at a concentration of 5 ng g-1 were 2.6 and 3.2%, respectively. The developed method has been successfully applied to 3-MCPD determination in refined edible oil samples including sunflower, corn, and canola oils.