Development a novel supramolecular solvent microextraction procedure for copper in environmental samples and its determination by microsampling flame atomic absorption spectrometry

A Low-Cost Colorimetric Assay for the Analytical Determination of Copper Ions with Consumer Electronic Imaging Devices in Natural Water Samples

This study reports a new approach for the determination of copper ions in water samples that exploits the complexation reaction with diethyldithiocarbamate (DDTC) and uses widely available imaging devices (i.e., flatbed scanners or smartphones) as detectors. Specifically, the proposed approach is based on the ability of DDTC to bind to copper ions and form a stable Cu-DDTC complex with a distinctive yellow color detected with the camera of a smartphone in a 96-well plate. The color intensity of the formed complex is linearly proportional to the concentration of copper ions, resulting in its accurate colorimetric determination. The proposed analytical procedure for the determination of Cu²⁺ was easy to perform, rapid, and applicable with inexpensive and commercially available materials and reagents. Many parameters related to such an analytical determination were optimized, and a study of interfering ions present in the water samples was also carried out. Additionally, even low copper levels could be noticed by the naked eye. The assay performed was successfully applied to the determination of Cu²⁺ in river, tap, and bottled water samples with detection limits as low as 1.4 µM, good recoveries (89.0-109.6%), adequate reproducibility (0.6-6.1%), and high selectivity over other ions present in the water samples.

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.

Supramolecular solvent-based micro-extraction of pesticides in food and environmental samples

Supramolecular solvent-based micro-extraction is a very important green technique for the isolation and pre-concentration of pesticide residues in food and environmental samples prior to their chromatographic analysis. The attractive features of supramolecular solvent-based micro-extraction include its simplicity, high pre-concentration factor, fastness, accuracy, low cost, less consumption of chemical reagents and environmental friendliness. The supramolecular solvent is generated from a ternary mixture of amphiphiles, water and a water miscible dispersion and coacervating solvent. Tehydrofuran is one of the solvents commonly used as both a dispersion solvent and a coacervating agent. This paper gives a recent comprehensive review on the application of alkanols as amphiphiles during supramolecular solvent-based micro-extraction of pesticide residues in food and environmental samples. Other researchers used long chain fatty acids as amphiphiles during pesticide analysis in food and environmental samples using supramolecular solvent-based micro-extraction, and this is discussed in this paper. The incorporation of ferrofluids in supramolecular solvents enables phase separation using a magnet instead of the time-consuming centrifugation technique. This paper also gives a detailed review of the application of ferrofluid-based supramolecular solvent micro-extraction of pesticide residues in food and environmental samples.

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.

Liquid phase microextraction techniques combined with chromatography analysis: a review

Sample pretreatment is the first and the most important step of an analytical procedure. In routine analysis, liquid–liquid microextraction (LLE) is the most widely used sample pre-treatment technique, whose goal is to isolate the target analytes, provide enrichment, with cleanup to lower the chemical noise, and enhance the signal. The use of extensive volumes of hazardous organic solvents and production of large amounts of waste make LLE procedures unsuitable for modern, highly automated laboratories, expensive, and environmentally unfriendly. In the past two decades, liquid-phase microextraction (LPME) was introduced to overcome these drawbacks. Thanks to the need of only a few microliters of extraction solvent, LPME techniques have been widely adopted by the scientific community. The aim of this review is to report on the state-of-the-art LPME techniques used in gas and liquid chromatography. Attention was paid to the classification of the LPME operating modes, to the historical contextualization of LPME applications, and to the advantages of microextraction in methods respecting the value of green analytical chemistry. Technical aspects such as description of methodology selected in method development for routine use, specific variants of LPME developed for complex matrices, derivatization, and enrichment techniques are also discussed.

Selective solvent bar micro-extraction as a single-step approach for the measurement of Cu fractions in seawater

Hollow fibre-supported liquid membrane was used for Cu fractionation in marine waters, using di-2-pyridylketone benzoylhydrazone (dPKBH) as a carrier due to its capacity to transport dissolved inorganic Cu at natural seawater pH. Optimized conditions were dPKBH (0.5 mmol L^-1), HNO₃ (0.5 mol L^-1) as acceptor agent, extraction time of 120 min and stirring speed of 800 rpm. Additionally, the selectivity of the method for the extraction of the inorganic Cu fraction was validated by comparing the experimental results with theoretical data, and a mathematical model was obtained for estimation of Cu linked to dissolved organic matter. The method was applied for the measurement of Cu fractions in real seawater samples. Results were successfully compared with the reference material BCR 403 and recovery analysis in waters from the Gulf of Cádiz, showing that it could be used as a simple approach for the study of different Cu fractions in marine waters. Graphical abstract.

State-of-the-art on the technique of dispersive liquid-liquid microextraction

Dispersive liquid-liquid microextraction is a new sample pretreatment technology based on traditional liquid liquid extraction. In this paper, the application of low-toxicity extractants such as low-density extractants, auxiliary extractants, stripping agents and ionic liquids in this technology and the extraction modes such as solvent de-emulsification, suspension extractant curing, auxiliary extraction, back extraction, and ionic liquid-dispersion liquid microextraction, are summarized. In addition, the synergism of this technique with other sample preparation techniques, such as liquid-liquid extraction, solid-phase extraction, solid-phase microextraction, dispersive solid phase extraction, matrix solid-phase dispersion extraction, supercritical fluid extraction and ultrasound-assisted dispersive liquid-liquid microextraction is discussed.

Ultrasonically formation of supramolecular based ultrasound energy assisted solidification of floating organic drop microextraction for preconcentration of methadone in human plasma and saliva samples prior to gas chromatography-mass spectrometry

In this work, an ultrasonic-assisted supramolecular based on solidification of floating organic drop microextraction (UA-SM-SFO-ME) was developed as a green method for preconcentration of methadone prior to gas chromatography-mass spectrometry (GC-MS). The supramolecular solvent aggregates containing reverse micelles of 1-dodecanol in tetrahydrofuran (THF) were formed by ultrasonication that subsequently dispersed in the sample solution. Ultrasonic waves caused the fast formation of supramolecular solvent aggregates. In this work, ultrasonication was used in two phases: First phase, the formation of reverse micelles and the second phase, the dispersion of supramolecular solvent in the sample solution. Actually, ultrasonication was basic of this presented work. In order to provide the highest extraction efficiency, the influence of various parameters on the method performance (supramolecular solvent type and volume, disperser solvent condition, pH, extraction time and salt concentration) was investigated. Based on the obtained optimum conditions, the limits of detection (LODs) and the limits of quantitation (LOQs) were obtained 0.5-1.2 µg L^-1 and 1.2-2.5 µg L^-1 with preconcentration factors in the range of 182-191, in water and biological samples, respectively. Subsequently, the method was assessed for preconcentration of the methadone in human plasma and saliva samples.

Development of a new emulsification microextraction method based on solidification of settled organic drop: application of a novel ultra-hydrophobic tailor-made deep eutectic solvent

In this research, a new microextraction method based on the solidification of settled organic drop (SSOD) was developed by coupling a novel tailor-made ultra-hydrophobic deep eutectic solvent (DES) with effervescence assisted emulsification microextraction.

The extraction of uranium using graphene aerogel loading organic solution

A new approach for uranium extraction employing graphene aerogel (GA) as a skeleton loading organic solution (GA-LOS) is proposed and investigated. Firstly, the GA with super-hydrophobicity and high organic solution absorption capacity was fabricated by one-step reduction and self-assembly of graphene oxide with ethylenediamine. By adsorbing Tri-n-butyl phosphate (TBP)/n-dodecane solution to prepare GA-LOS, the extraction of U(VI) from nitric acid medium using GA-LOS was investigated and compared with conventional solvent extraction. It is found that the GA-LOS method can provide several advantages over conventional solvent extraction and adsorption due to the elimination of aqueous-organic mixing-separation procedures and easy solid-liquid separation. Furthermore, it also possesses higher extraction capacity (the saturated extraction capacity of GA loading TBP for U(VI) was 316.3mgg^-1 ) and lower consumption of organic diluents, leading to less organic waste. Moreover, the stability of GA-LOS in aqueous solution and cycling test were also studied, and it shows a remarkable regeneration capability, making it an ideal candidate for metal extraction from aqueous solution.

A new supramolecular based liquid solid microextraction method for preconcentration and determination of trace bismuth in human blood serum and hair samples by electrothermal atomic absorption spectrometry

A simple and reliable supramolecule-aggregated liquid solid microextraction method is described for preconcentration and determination of trace amounts of bismuth in water as well as human blood serum and hair samples. Catanionic microstructures of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactants, dissolved in deionized water/propanol, are used as a green solvent to extract bismuth (III)-diethyldithiocarbamate complexes by dispersive microextraction methodology. The extracted solid phase is easily removed and dissolved in 50 μL propanol for subsequent measurement by electrothermal atomic absorption spectrometry (ET-AAS). The procedure benefits the merits of supramolecule aggregates' properties and dispersive microextraction technique using water as the main component of disperser solvent, leading to direct interaction with analyte. Phase separation behavior of extraction solvent and different parameters influencing the extraction efficiency of bismuth ion such as salt concentration, pH, centrifugation time, amount of chelating agent, SDS:CTAB mole ratio, and solvent amounts were thoroughly optimized. Under the optimal experimental conditions, the calibration curve was linear in the range of 0.3-6 μg L^-1 Bi (III) with a limit of detection (LOD) of 0.16 μg L^-1 (S/N = 3). The relative standard deviations (RSD) of determination were obtained to be 5.1 and 6.2 % for 1 and 3 μg L^-1 of Bi (III), respectively. The developed method was successfully applied as a sensitive and accurate technique for determination of bismuth ion in human blood serum, hair samples, and a certified reference material.

Supramolecular solvent-based dispersive liquid–liquid microextraction of copper from water and hair samples

A supramolecular solvent based dispersive liquid–liquid microextraction (SM-DLLME) procedure has been established for the separation and preconcentration of Cu(ii) before its determination by microsampling flame atomic absorption spectrometry.

Supramolecular solvent-based microextraction method for cobalt traces in food samples with optimization Plackett–Burman and central composite experimental design

A new microextraction method based on formation of supramolecular solvent (Ss) was developed by using of chemometric optimization method for cobalt determination with microsampling flame atomic absorption spectrometry (MS-FAAS).

Synthesis and characterization of diphenylcarbazide-siliceous mesocellular foam and its application as a novel mesoporous sorbent for preconcentration and trace detection of copper and cadmium ions

We are introducing diphenylcarbazide functionalized siliceous mesocellular foam as a novel mesoporous solid-phase for the extraction of heavy metal ions including copper(ii) and cadmium(ii).

Ligandless ultrasonic-assisted and ionic liquid-based dispersive liquid-liquid microextraction of copper, nickel and lead in different food samples

A simple and rapid ultrasonic assisted-ionic liquid based-liquid-liquid microextraction (UA-IL-DLLME) method has been developed for the enrichment and separation of Cu(II), Ni(II) and Pb(II). A two level factorial design was used to determine the effect of key factors such as pH, volume of ionic liquid (IL), carbon tetra chloride (CCl4) and sonication time (St). 1-Butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) and CCl4 were used as an extractant and dispersant solvent, respectively. The accuracy of the proposed method was evaluated by analysing of SRM Apple Leaves 1515 certified reference material. The limits of detections (LODs) were 0.17 μg/L, 0.49 μg/L and 0.95 μg/L for Cu, Ni and Pb, respectively. The enrichment factor (EF) was 100. The method has been successfully applied for the analysis of the content of Cu, Ni and Pb in spice, vegetable and fruit samples by flame atomic absorption spectrometry (FAAS).

Supramolecular solvent microextraction of gold prior to its determination by microsample injection system coupled with flame atomic absorption spectrometry

A supramolecular solvent based liquid–liquid microextraction (SsLLME) system for gold was developed prior to its determination by a microsample injection system coupled with flame atomic absorption spectrometric (MS-FAAS).