Separation and preconcentration of aluminum in parenteral solutions and bottled mineral water using different analytical techniques

[Research progress of solid phase extraction materials in the application of metal ion pretreatment]

Monitoring of trace heavy metal pollutants released during industrial and agricultural processes is essential because of their widespread distribution in the environment and health hazards. Several techniques, including inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-optical emission spectrometry (ICP-OES), electrothermal atomic absorption (ETAAS), and flame atomic absorption spectrometry (FAAS), have been proposed for the determination of heavy metals in serum, plasma, whole blood, and food. All these techniques have earned robust recognition in the field of trace heavy metals and have many advantages such as multi-elemental analysis capability, large dynamic linear range, low detection limits, and high productivity. Nevertheless, most of the recommended techniques require digestion of the sample and extraction with an organic solvent for isolation of the metal ion from the sample solution prior to analysis. Despite improvements in the performance of modern analytical instruments, the direct determination of heavy metal ions in real samples is difficult because of their low concentration levels and matrix interference. Thus, extraction and clean-up steps are required for pre-concentration of the analyte, so that detection and elimination of the interfering matrix component are possible. Solid-phase extraction (SPE) is one of the popular metal ion pretreatment methods. The advantages of SPE include easy cartridge/column regeneration, high analytical frequency, and high preconcentration factors for sorbents with high adsorption capacities. On the other hand, when the analytes are extracted from a complex matrix such as serum and meat samples, large amounts of proteins from the samples can be retained on the sorbent surface, obstructing the binding sites on the sorbent and leading to poor precision and accuracy. The key to metal ion detection is the development of new SPE materials with high efficiency and enrichment factors as well as an effective pretreatment technology. Nanomaterials such as restricted-access carbon nanotubes, nanoadsorbents, nanoparticle carriers, and magnetic nanoparticles have shown great promise in advancing biomedical and environmental analysis because of the unique properties originating from their ultrafine dimensions. Nanomaterials can provide large specific surface areas and tunable functional groups to facilitate metal ion absorption. They could also possess superior optical properties and allow for high sensitivity in simple fluorescent or colorimetric detection methods. Owing to their excellent mechanical and chemical stability, polymer materials have been of great interest as adsorbents for the SPE of metal ions from solution. Moreover, a designed polymeric material can show triple functionality such as physical adsorption, chelate formation, and ion exchange for the target metal ions. A dual-functional nanomaterial-DNAzyme platform can simultaneously allow for the sensitive detection and effective removal of heavy metal ions in water. Thus, this platform can serve as a simple, cost-effective tool for rapid and accurate metal quantification in the determination of human metal exposure and inspection of environmental contamination. Furthermore, the new photocaged chelator can uncage and release the combined metal ions into an aqueous solution that is free of the other components of the matrix. In this manner, we can develop diagnostic tests for metal ions that are often difficult to detect using other methods. In this paper, the characteristics of new SPE materials, including nanomaterials, polymer materials, and functional materials as well as advances in their applications to the preparation of complex samples are summarized, and the direction for future development is proposed.

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.

Evaluate the exposure of toxic metals via drinking water and smoking nonbranded cigarette in malnourished women by modified single/two-step cloud point extraction

Presently, the exposure of heavy metals (cadmium and lead) was determined in biological sample (serum) of women (pregnant and nonpregnant) who belong to low socioeconomic group (malnutrition). The cadmium (Cd) and lead (Pb) were determined in drinking water and locally produced cigarette (bidi), smoking by women of childbearing age. The preconcentration of heavy metals in serum, water, and tobacco of bidi were carried out by cloud point extraction at single and two-step methods before determination by atomic absorption spectrometry with flame mode. The Cd and Pb in the water- and acid-digested serum and tobacco samples were treated with a complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN). The hydrophobic complex of Cd and Pb was entrapped in Triton X-114. For the first step, the entrapped analytes in Triton X-114 was diluted with alcoholic acid (0.2 mol/L of HNO₃) and subjected to FAAS, whereas for the second step of CPE, the surfactant-rich analyte was subjected to the second round of enrichment method. Lastly, the analyte was back-extracted in acidic solution (0.2 mol/L) and analyzed by FAAS. The all significant variable was optimized for optimal recovery of Cd and Pb. The recommended single/two-step cloud point extraction method was validated by simultaneously evaluated matrices matched certified reference materials of water, serum, and tobacco. The resulted data indicated that the groundwater samples contained elevated concentrations of Cd and Pb than recommended values for drinking water by WHO, while the contents of Cd and Pb were observed about two-fold higher in nonbranded cigarette (bidi) than branded cigarette. It was observed that there were about 3 to 4 times higher concentrations of both toxic metals in blood serum of smoker malnourished women group than in referent nonsmoker women. Graphical abstract.

Evolution of Environmentally Friendly Strategies for Metal Extraction

The demand for the recovery of valuable metals and the need to understand the impact of heavy metals in the environment on human and aquatic life has led to the development of new methods for the extraction, recovery, and analysis of metal ions. With special emphasis on environmentally friendly approaches, efforts have been made to consider strategies that minimize the use of organic solvents, apply micromethodology, limit waste, reduce costs, are safe, and utilize benign or reusable materials. This review discusses recent developments in liquid- and solid-phase extraction techniques. Liquid-based methods include advances in the application of aqueous two- and three-phase systems, liquid membranes, and cloud point extraction. Recent progress in exploiting new sorbent materials for solid-phase extraction (SPE), solid-phase microextraction (SPME), and bulk extractions will also be discussed.

Preconcentrations of Ni(II) and Co(II) by using immobilized thermophilic Geobacillus stearothermophilus SO-20 before ICP-OES determinations

This study deals with the preconcentrations of Ni(II) and Co(II) ions in real samples using the solid phase extraction method (SPE) before their determinations by inductively coupled plasma optical emission spectrometry (ICP-OES). Thermophilic bacterium Geobacillus stearothermophilus SO-20 (Accession number: KJ095002), loaded with Amberlite XAD-4, was utilized as a novel biosorbent. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope (SEM) were employed for the investigation of the bacterial surface before and after Ni(II) and Co(II) biosorption. The experimental parameters were examined to find the best conditions. The retained Ni(II) and Co(II) ions on the biosorbent were eluted by using 5.0 ml of 1.0 mol l^-1 HCI as the best eluent. The sorption capacities were found to be 16.8 mg g^-1 for Ni(II) and 21.6 mg g^-1 for Co(II). It was also successfully used for the quantification of Ni(II) and Co(II) in a river water sample, some vegetables and soil.

Boletus edulis loaded with γ-Fe2O3 nanoparticles as a magnetic sorbent for preconcentration of Co(II) and Sn(II) prior to their determination by ICP-OES

The authors show that the fungus Boletus edulis loaded with γ-Fe₂O₃ nanoparticles is a viable sorbent for magnetic solid phase extraction of trace levels of Co(II) and Sn(II). The surface structure of immobilized magnetized B. edulis was characterized by FT-IR, SEM and EDX. Experimental parameters were optimized. Following elution with 1 M HCl, the ions were quantified by ICP-OES. The limits of detection are 21 pg·mL^-1 for Co(II), and 19 pg·mL^-1 for Sn(II). The preconcentration factors are 100 for both ions. The sorption capacities of the sorbent are 35.8 mg·g^-1 for Co(II) and 29.6 mg·g^-1 for Sn(II). The method was applied to the analysis of certificated reference materials and gave ≥95% recoveries with low RSDs. It was also successfully applied to the quantification of Co(II) and Sn(II) in spiked environmental and food samples. Graphical abstract The fungus Boletus edulis loaded with γ-Fe₂O₃ nanoparticles is a viable biosorbent for magnetic solid phase extraction (MSPE) of trace levels of Co(II) and Sn(II). The surface structure of immobilized magnetized B. edulis was characterized by FT-IR, SEM and EDX. Experimental parameters were optimized.

Inorganic arsenic speciation in water samples by miniaturized solid phase microextraction using a new polystyrene polydimethyl siloxane polymer in micropipette tip of syringe system

The polymer, polystyrene polydimethyl siloxane was loaded into the micropipette tip of the syringe system as an adsorbent to developed miniaturized solid phase microextraction. Standard solutions of arsenate and arsenite were passed through the adsorbent loaded in micropipette tip to check the adsorption behaviors. It was observed that arsenate adsorbed on the polystyrene polydimethyl siloxane in the pH rang of 6-8, while arsenite was directly passed through the micropipette tip of syringe system. The adsorbed arsenate in micropipette tip of syringe system were eluted by 1.0M hydrochloric acid. The total inorganic arsenic contents were obtained by the addition of oxidizing agent potassium permanganate into the studied samples before passing to the micropipette tip of syringe system. Arsenite concentration in water samples were measured by subtracting arsenate from total inorganic arsenic concentration. Different characteristics which effect the determination of arsenate specie like amount of adsorbent, adsorption capacity, pH, pulled and pushed cycles for adsorption and desorption, volume of sample, eluent type and it volume were also studied in detail. Enrichment factor and detection limit of arsenate by desired method were 218 and 6.9ngL^-1 respectively. The relative standard deviation was 4.1% (n=10, C=0.12µgL^-1). Accuracy of the desired technique was confirmed by analysis of the CRMs (Lake Ontario Water TM-28.3 and Riverine Water NRCC-SLRS-4). Desired technique was significantly useful for determination of the total arsenic, arsenate, and arsenite contents in different natural water samples.

A novel 4-(2-pyridylazo) resorcinol functionalised magnetic nanosorbent for selective extraction of Cu(II) and Pb(II) ions from food and water samples

This paper describes a novel sorbent based on 4-(2-pyridylazo) resorcinol functionalised magnetic nanoparticles and its application for the extraction and pre-concentration of trace amounts of Cu(II) and Pb(II) ions. The nanosorbent was characterised by Fourier transform infrared spectroscopy, X-ray powder diffraction, thermal analysis, elemental analysis and scanning electron microscopy. The effects of various parameters such as pH, sorption time, sorbent dosage, elution time, volume and concentration of eluent were investigated. Following the sorption and elution of analytes, Cu(II) and Pb(II) ions were quantified by flame atomic absorption spectrometry. The limits of detection were 0.07 and 0.7 μg l(-1) for Cu(II) and Pb(II), respectively. The relative standard deviations of the method were less than 7%. The sorption capacity of this new sorbent were 92 and 78 mg g(-1) for Cu(II) and Pb(II), respectively. Finally this nanosorbent was applied to the rapid extraction of trace quantities of Cu(II) and Pb(II) ions in different real samples and satisfactory results were obtained.

Complex-forming organic ligands in cloud-point extraction of metal ions: a review

Cloud-point extraction (CPE), an easy, safe, environmentally friendly, rapid and inexpensive methodology for preconcentration and separation of trace metals from aqueous solutions has recently become an attractive area of research and an alternative to liquid-liquid extraction. Moreover, it provides results comparable to those obtained with other separation techniques and has a greater potential to be explored in improving detection limits and other analytical characteristics over other methods. A few reviews have been published covering different aspects of the CPE procedure and its relevant applications, such as the phenomenon of clouding, the application in the extraction of trace inorganic and organic materials, as well as pesticides and protein substrates from different sources, or incorporation of CPE into an FIA system. This review focuses on general properties of the most frequently used organic ligands in cloud-point extraction and on literature data (from 2000 to 2012) concerning the use of modern techniques in determination of metal ions' content in various materials. The article is divided according to the class of organic ligands to be used in CPE.

Preconcentration, separation and spectrophotometric determination of aluminium(III) in water samples and dialysis concentrates at trace levels with 8-hydroxyquinoline-cobalt(II) coprecipitation system

A separation-preconcentration procedure was developed for the determination of trace amounts of aluminium in water samples and dialysis concentrates by UV-vis Spectrophotometry after coprecipitation using 8-hydroxyquinoline (8-HQ) as a chelating agent and Co(II) as a carrier element. This procedure is based on filtration of the solution containing precipitate on a cellulose nitrate membrane filter following aluminium(III) coprecipitation with Co/8-HQ and then the precipitates together with membrane filter were dissolved in concentrated nitric acid. The metal contents of the final solution were determined by UV-vis Spectrophotometry with Erio Chrome Cyanine-R standard method. Several parameters including pH of sample solution, amount of carrier element and reagent, standing time, sample volume for precipitation and the effects of diverse ions were examined. The enrichment factor was calculated as 50 and the detection limits, corresponding to three times the standard deviation of the blank (N: 10), was found to be 0.2 microg L(-1). The accuracy of the method was tested with standard reference material (CRM-TMDW-500) and spiked addition. Determination of aluminium(III) was carried out in sea water, river water, tap water and haemodialysis fluids samples. The recoveries were >95%. The relative standard deviations of determination were less than 6%.

Cloud point extraction of vanadium in pharmaceutical formulations, dialysate and parenteral solutions using 8-hydroxyquinoline and nonionic surfactant

A cloud point extraction (CPE) method has been developed for the determination of trace quantity of vanadium ions in pharmaceutical formulations (PF), dialysate (DS) and parenteral solutions (PS). The CPE of vanadium (V) using 8-hydroxyquinoline (oxine) as complexing reagent and mediated by nonionic surfactant (Triton X-114) was investigated. The parameters that affect the extraction efficiency of CPE, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of CPE of V was checked by standard addition method in real samples. The extracted surfactant-rich phase was diluted with nitric acid in ethanol, prior to subjecting electrothermal atomic absorption spectrometry. Under these conditions, the preconcentration of 50 mL sample solutions, allowed raising an enrichment factor of 125-fold. The lower limit of detection obtained under the optimal conditions was 42 ng/L. The proposed method has been successfully applied to the determination of trace quantity of V in various pharmaceutical preparations with satisfactory results. The concentration ranges of V in PF, DS and PS samples were found in the range of 10.5-15.2, 0.65-1.32 and 1.76-6.93 microg/L, respectively.