Supramolecular Solvent-based Liquid Phase Microextraction Research Articles

A new sample treatment strategy based on supramolecular solvent for determination of herbicide residues in water samples by Box-Behnken design

This paper describes a sensitive, simple and green analytical method for pretreatment of sulfonylurea and pyrethroid herbicides in water samples by supramolecular solvent-based liquid phase microextraction (SUPRAS-LPME). The SUPRAS was rapidly formed by nonanoic acid and tetrahydrofuran (THF)/water solution. The attractive features of SUPRAS-LPME include the simplicity, high enrichment factor, low cost and less consumption of organic solvents. The main influencing factors including type and volume of fatty acids, volume of THF, ionic strength, vortex time and volume of formic acid were optimized in detail, and then the significant variables were optimized by Box-Behnken design (BBD). Under the optimized condition, the proposed method shows high precision (RSDs < 13.7 %), low limits of detection (0.5–10 μg L-1) and limits of quantitation (10–45 μg L-1), acceptable recovery (71.3 %-95.9 %). The proposed method was successfully applied for analysis of sulfonylurea and pyrethroid herbicides in water samples, making it an alternative analytical strategy for determination of trace analytes at the microgram per liter range with desirable sensitivity.

Accurate and sensitive analytical method for trace iron determination in clove tea and tap water samples by slotted quartz tube-flame atomic absorption spectrometry after its preconcentration with supramolecular solvent-based liquid-phase microextraction

A green supramolecular solvent-based liquid-phase microextraction (SUPRAs-LPME) strategy was developed and used for the preconcentration of iron in clove tea and tap water samples at trace levels. Complex formation occurred between the iron and a Schiff base ligand obtained from 5-bromosalicylaldehyde and o-phenylenediamine reaction, and the coordinate complex formed was extracted to supramolecular solvent phase. Limit of detection and quantification values was found as 4.3 and 14.2 μgL−1, respectively, under the optimized conditions. When the analytical performance values obtained with SQT-FAAS, SUPRAs-LPME-FAAS and SUPRAs-LPME-SQT-FAAS are compared with FAAS, enhancements in detection power based on the LOD comparisons were calculated as 1.8, 31.4 and 65.8 times, respectively. The presented method was successfully applied to the determination of water-soluble iron in real clove tea in addition to tap water samples at trace levels, and the percent recoveries were obtained as 94.7–103.0% and 96.9–107.6%, respectively.

Green Supramolecular Solvent-Based Liquid-Phase Microextraction Method for Spectrophotometric Determination of Aluminum in Food, Water, Hair and Urine Samples

Background: Aluminum Al(III) is the most significant metal in the earth's crust to which humans are frequently exposed and has several industrial applications. On the other hand, Al (III) has high potential toxic impacts on some human pathologies like Parkinson and Alzheimer's disease. So, it is very important to monitor and determine the trace level of Al (III) in various environmental and biological samples. Objective: In the present work, a novel green supramolecular Solvent-Based Liquid-Phase Microextraction (SS-LPME) procedure has been developed to preconcentrate and determine aluminum (III) in various real samples. Methods: The proposed procedure was based on the application of 1-decanol/THF as a Supramolecular Solvent (SS) system and quinalizarin as a chelating agent. Al(III)-quinalizarin hydrophobic complex was obtained at pH 7.0, extracted into supramolecular solvent phase (1- decanol/THF), centrifuged and then measured spectrophotometrically at 580 nm. The impact of different analytical parameters on the microextraction efficiency was studied and optimized. The validation of the proposed preconcentration procedure was checked using certified reference materials. Results: The calibration curve was linear in the range of 2.0-150 μg L-1. The developed method has preconcentration factor of 40 and detection limit (LOD) was 0.20 μg L-1. The precision of the method was confirmed with low relative standard deviation (RSD ≤ 1.0%). Conclusion: This study explores the effectiveness of quinalizarin for the first time together with SS to develop green SS-LPME method to preconcentrate and separate trace quantities of Al (III) in real water, fruit juice, food, hair, and urine samples collected from Saudi Arabia.

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 0.035ngmL-1, 0.1ngmL-1, 0.1-300ngmL-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.

Micelle-based restricted access ion-pair microextraction of phosphate at trace levels in water samples for separation, preconcentration and determination

Abstract A new and simple micelles-rich restricted access supramolecular solvent-based liquid phase microextraction method (RASUPRASs-LPME) based on the ion-pair complex formation of phosphate (PO4 3-) ions with ammonium heptamolybdate and malachite green in acidic medium was developed. The phosphate ion concentration after microextraction of the ion-pair complex to the hexagonal aggregates of decanoic acid (DA) was measured with micro-volume UV-Vis spectrophotometer at 625 nm. All analytical parameters which are effective on the method such as acid type and concentration, supramolecular solvent volume, amount of the components forming the complex, sample volume, were optimized. The preconcentration factor (PF), limit of detection (LOD) and limit of quantification (LOQ) for the developed method was found to be 15, 9.6 and 32.1, respectively. The RA-SUPRAs-LPME method was finally applied for the analysis of the phosphate content of different types of water samples.

Supramolecular solvents formation in aqueous solutions containing primary amine and monoterpenoid compound: Liquid phase microextraction of sulfonamides

A phenomenon of supramolecular solvents formation in aqueous solutions containing primary amine and monoterpenoid compound is presented for the first time. A novel supramolecular solvent-based liquid phase microextraction was developed. In an aqueous phase primary amine formed isotropic solution due to formation of amphiphile supramolecular assembly. The phase separation was achieved by a coacervation process. The monoterpenoid phenol (thymol) acted as a coacervation agent and induced spontaneous in situ formation of tiny supramolecular solvent droplets. The applicability of the proposed microextraction procedure was demonstrated for the separation of sulfonamides from biological fluids (human plasma and serum). An obtained composition of supramolecular solvent (1-decylamine, thymol, water) promoted satisfactory extraction of polar analytes from aqueous phase. The calibration graphs were linear over the concentration ranges of 0.06–50 mg L−1 for sulfamethoxazole, sulfamethazine and sulfapyridine. The limit of detection calculated from the blank tests based on 3σ was 0.02 mg L−1 for all analytes. The total analysis time was 15 min.

Supramolecular Solvent-Based Liquid Phase Microextraction Combined with Ion-Pairing Reversed-Phase HPLC for the Determination of Quats in Vegetable Samples.

In this study, we used anion supramolecular solvent (SUPRAS) prepared from a mixture of an anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic surfactant, tetrabutylammonium bromide (TBABr), as the extraction solvent in liquid phase microextraction (LPME) of paraquat (PQ) and diquat (DQ). The enriched PQ and DQ in the SUPRAS phase were simultaneously analyzed by ion-pairing reversed-phase high performance liquid chromatography. PQ and DQ were successfully extracted by LPME via electrostatic interaction between the positive charge of the quats and the negative charge of SUPRAS. PQ, DQ, and ethyl viologen (the internal standard) were separated within 15 min on a C18 column, with the mobile phase containing 1-dodecanesulfonic acid and triethylamine, via UV detection. The optimized conditions for the extraction of 10 mL aqueous solution are 50 μL of SUPRAS prepared from a mixture of SDS and TBABr at a mole ratio of 1:0.5, vortexed for 10 s at 1800 rpm, and centrifugation for 1 min at 3500 rpm. The obtained enrichment factors were 22 and 26 with limits of detection of 1.5 and 2.8 µg L−1 for DQ and PQ, respectively. The precision was good with relative standard deviations less than 3.86%. The proposed method was successfully applied for the determination of PQ and DQ in vegetable samples and recoveries were found in the range of 75.0% to 106.7%.

A new environment-friendly supramolecular solvent-based liquid phase microextraction coupled to high performance liquid chromatography for simultaneous determination of six phenoxy acid herbicides in water and rice samples

A green supramolecular solvent (SUPRAS) has been ex situ synthesized and used as the extraction solvent for liquid phase microextraction (LPME) for six phenoxy acid herbicides including 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy)propanoic acid (Dichloprop), 2-(4-Chloro-2-methylphenoxy) propanoic acid (Mecoprop), 4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB) and 4-(4-Chloro-2-methylphenoxy) butanoic acid (MCPB) before their analysis by HPLC. The SUPRAS was generated from the aggregation of sodium dodecyl sulfate (SDS) and tetrabutylammonium bromide (TBABr) at the molar ratio of 1:4, in the presence of AlCl3 at ambient temperature. The synthesized SUPRAS was found to be stable for at least one month and a single prepared batch can be used for extraction of 12 samples. The optimum conditions for the extraction were 20 µL of SUPRAS, 3.5% (w/v) of AlCl3, vortex for 20 s and centrifugation at 6000 rpm for 1 min. The micro-volume extraction phase was settled at the narrow bottom of the centrifugation tube allowing easy collection without any special equipment required, providing high efficiency and reproducibility for HPLC analysis. Under the optimum conditions, the method provided the enhancement factor of 37–149 with the limits of detection in the range of 1–2 µg L − 1. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) was used for rice sample preparation before extraction and analysis by HPLC. The proposed method was successfully applied for the analysis of the studied herbicides in water and rice samples with the good percentage recovery ranged from 81–110 and 81–108, respectively.

An environment-friendly supramolecular solvent-based liquid–phase microextraction method for determination of aluminum in water and acid digested food samples prior to spectrophotometry

Aluminum (III) has high toxic impacts in some human pathologies like renal osteodystrophy, Parkinson's and Alzheimer's disease. So, it is very important to assess and determine the trace concentrations of Aluminum (III) in various water and acid digested food samples. The present work proposed a new green supramolecular solvent liquid–phase microextraction procedure has been sophisticated to preconcentrate and determine Aluminum (III) in various samples. The proposed method was based on the application of Undecanol/THF supramolecular solvent system and thymol blue as a chelating agent. Aluminum (III)-thymol blue complex was formed at pH 6.0, extracted into (Undecanol/THF) supramolecular solvent phase, centrifuged and spectrophotometrically measured at 550 nm. The influence of different analytical parameters was studied and optimized. The validation of the suggested preconcentration method was checked using certified reference materials. The calibration curve was linear in the range of 5.0–200 μg L−1. The developed method has preconcentration factor of 50 and detection limit was 1.20 μg L−1. The method precision was confirmed with relative standard deviation ≤1.80%. The accuracy of the new preconcentration procedure was checked by the analysis of the certified reference materials (SRM 1643e trace element in water and NIST SRM 1515 Apple Leaves), and successfully applied to determine Aluminum (III) in real samples with relative recovery values in the range of 95.0%–100% for the spiked samples. This study explores the effectiveness of thymol blue for the first time together with supramolecular solvent to develop green supramolecular solvent liquid–phase microextraction method to preconcentrate and separate of trace amount of Aluminum (III) in real samples.

Supramolecular solvent-based liquid phase microextraction of malachite green at trace level from water samples for its UV–vis spectrophotometric detection

ABSTRACT A simple and fast microextraction procedure based on supramolecular solvent extraction of malachite green from water samples has been established in the presented work. The effective analytical parameters including pH, solvent volume, sample volume etc. on the quantitative recoveries of the malachite green were optimised. Matrix effects were also investigated. The preconcentration factor was found as 50. The limit of detection and limit of quantification were 16.3 and 54.5 µg L−1, respectively. The relative standard deviation percentage was below 7%. The presented procedure was applied to the determination of malachite green content of natural water samples from fish farm and tap water etc.

Development of an ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction (UA-RAS-LPME) method for separation-preconcentration and UV-VIS spectrophotometric detection of curcumin

ABSTRACTEnvironment-responsive long chain acid (C7–C14)-based supramolecular solvents (SUPRAs) were produced and their potential usage for microextraction of curcumin was assessed in the presented work. The SUPRAs were prepared by mixing of decanoic acid with tetrahydrofuran. The ultrasonic-assisted restricted access supramolecular solvent liquid phase microextraction of curcumin was achieved at pH 6 by 200 µL of using SUPRAs. Various parameters including pH, solvent volume, ultrasonication time, and sample volume were optimized. The limit of detection, limit of quantification, relative standard deviation %, and preconcentration factor were 5.3 µg L−1, 17.5 µg L−1, 2.2%, and 50, respectively. The accuracy of method was checked by additional-recovery experiments.

Multivariate statistical design optimization for ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction of quercetin in food samples

In this method, quercetin as a flavonoid has been extracted, preconcentrated and determined by using ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction method in food samples. The quercetin concentration in extraction phase was determinated by UV–visible spectrophotometer which has microsampling cuvette. Multivariate statistical design approach was used to optimize the analytical variables including the pH, ratio of restricted access solvent components, volume of restricted access solvent, ultrasonication and centrifugation times. The analytical performance values of the developed method including limit of detection, limit of quantification, preconcentration factor and relative standard deviation (10 replicates of 10–5 M of quercetin solution) were found as 2.98, 9.93 μg L−1, 30 and 6.3%, respectively. The method provides important advantages such as use of minimum volume of organic solvents, simple and economical operation and easy optimization via multivariate statistical design approach. The developed procedure was validated with four food samples, and acceptable recoveries (87–104%) were achieved.

Ultrasonic-assisted supramolecular solvent-based liquid phase microextraction of mercury as 1-(2-pyridylazo)-2-naphthol complexes from water samples

ABSTRACTA separation-preconcentration method based on supramolecular solvent ultrasonic-assisted liquid-phase microextraction (Ss-USA-LPME) for spectrophotometric determination of mercury as 1-(2-pyridylazo)-2-naphthol (PAN) chelates has been established. Red coloured Hg(II)-PAN hydrophobic complex was extracted into the supramolecular phase (1-decanol/THF) at pH 9.5. The extract was separated from aqueous phase by centrifugation, diluted with ethanol and determined by UV–Vis spectrophotometer at λmax = 560 nm. The influences of important analytical parameters such as pH, amount of PAN, 1-decanol and THF, sample volume and matrix effects for the quantitative recoveries were examined and optimised. Under the optimised experimental conditions, the amount of ligand, 1-decanol and THF were 1.0 × 10–4 M, 200 µL and 300 µL, respectively. The optimum time of ultrasonic bath and centrifugation were found as 2 min and 5 min. A linear calibration graph was obtained linearly in the concentration ranges of 8.3–1000 µg L−1. The preconcentration factor was obtained as 20. The limit of detection (LOD) was 2.6 µg L−1 with the relative standard deviation (RSD) of 2.4% for mercury (C = 100 µg L−1, n = 7). The validity of the developed Ss-USA-LPME technique was checked with a certified reference material of NIST 1641d. The presented method has been successfully applied to the determination of mercury in water samples.