Preconcentration Of Traces Research Articles

Evaluation of Lead Ion in the Wastewater of the Lifting and Treatment Stations Using ICP-MS and CPE Methods

To pre-concentrate trace amounts of lead before determining it by UV-vis spectrophotometer, a new method for micelle-mediated phase separation has been created. The process depends on the extraction of lead from iodine media using Triton X-114 in the cloud point extraction method without the need for any chelating agents, where the optimal conditions for the method were achieved, which temperature 50 °C, pH 4, and 30 mmol L−1 concentration of KI, 0.3 mL of 2% (v/v) Triton X-114, and time of 10 min in the water bath. Linearity was followed between 1 and 16 µg/mL of lead concentration. The method's lead detection limit is 0.1 µg/mL and %RSD 3.633. Additionally, the interference impact of certain cations was evaluated. The proposed technique was successfully applied to determine the lead ion in the wastewater in ten different stations in the center and district of Al-Hur in Karbala City. The lead ion of the wastewater of the stations under study was also determined directly using inductively coupled plasma-mass spectrometry (ICP-MS) technology comparing its results with the new method and performing the statistical analysis of both methods. The p-value was less than 0.05, showing significant differences between both methods.

MWCNT@TiSiO4 nanocomposite for dispersive solid phase extraction of traces cadmium in food and environmental samples

Cadmium contamination presents substantial hazards to both human health and the environment due to its persistent presence in ecosystems and toxic characteristics. It accumulates in soil and water, causing chronic renal and respiratory issues, and carcinogenicity. Effective detection for monitoring the environmental and public health effects of Cd is required. This study addresses a new separation and enrichment method with a novel MWCNT@TiSiO4 nanocomposite synthesized via sol-gel and calcination synthesis techniques. A comprehensive characterization of the nanocomposite was conducted utilizing X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, and Field Emission-Scanning Electron Microscopy (FE-SEM) techniques. The nano-sorbent was utilized in conjunction with dispersive solid phase extraction (DSPE) to separate and preconcentrate trace amounts of Cd(II) prior to its determination by using flame atomic absorption spectrometry (FAAS). The optimization of analytical parameters, including pH, sample and eluent volumes, sorbent quantities, and eluent composition, was studied. The effect of matrix components was investigated. The method showed a low limit of detection (LOD), limit of quantification (LOQ), and relative standard deviation (%RSD) of 0.053 ng mL−1, 0.176 ng mL−1, and 4.6%, respectively. The method was validated by analyzing certified reference materials. The developed methodology was applied to determine Cd(II) levels in water, tobacco, and food samples. The recovery values were quantitative (90–101%). The maximum and minimum concentrations of Cd in food samples were in shrimp (47.87 ng g−1) and lentil (11.25 ng g−1), respectively.

Dispersive Micro-Solid Phase Extraction Using a Graphene Oxide Nanosheet with Neocuproine and Batocuproine for the Preconcentration of Traces of Metal Ions in Food Samples.

A dispersive micro-solid phase extraction (Dµ-SPE) method for the preconcentration of trace metal ions (Pb, Cd, Cr, Mn, Fe, Co, Ni, Cu, Zn) on graphene oxide with the complexing reagents neocuproine or batocuproine is presented here. Metal ions form cationic complexes with neocuproine and batocuproine. These compounds are adsorbed on the GO surface via electrostatic interactions. The factors affecting the separation and preconcentration of analytes such as pH, eluent (concentration, type, volume), amount of neocuproine, batocuproine and GO, mixing time, and sample volume were optimized. The optimal sorption pH was 8. The adsorbed ions were effectively eluted with 5 mL 0.5 mol L-1 HNO3 solution and determined by the ICP-OES technique. The preconcentration factor for the GO/neocuproine and GO/batocuproine in the range 10-100 and 40-200 was obtained for the analytes, with detection limits of 0.035-0.84 ng mL-1 and 0.047-0.54 ng mL-1, respectively. The method was validated by the analysis of the three certified reference materials: M-3 HerTis, M-4 CormTis, and M-5 CodTis. The procedure was applied to determine metal levels in food samples.

Design, Synthesis and Application of Chemically Modified Amberlite XAD‐2 for Separation and Preconcentration of Pb(II)

AbstractA highly selective, efficient, green analytical method was developed to separate and preconcentrate trace amounts of lead from aqueous samples using gallic acid‐immobilized Amberlite XAD‐2. The method was designed by determining the stability constant of the Pb‐GA complex and plotting the chemical speciation diagram, which indicated strong complexation of Pb(II) with GA (log βPb‐GA=9.50). The species distribution curve for the Pb‐GA complex indicates almost 98 % complexation, forming Pb‐GA as the predominant species. Considering the strong interaction of GA toward the lead, GA was immobilized on the polymeric matrix of Amberlite XAD‐2, and the conditions for the uptake of lead from the aqueous solutions were optimized by both batch and column methods. The sorption capacity and concentration factor of modified Amberlite XAD‐2 for Pb(II) were found to be 4554 μg g−1 and100 respectively. The method was employed for the determination of lead in various wastewater samples. Molecular modeling studies were also performed on GA‐immobilized Amberlite XAD‐2 to determine the active structure of GA on the surface.

Removing of some heavy metals from cutting rock samples by using nano graphene oxide

A modified Totland's approach was used to separate and preconcentrate trace elements from cutting rock samples obtained from different depths of oil fields in Maysan Province, Iraq. FT-IR, UV-Vis spectrophotometer, (XRD) X-ray diffraction spectroscopy, (ZP) Zeta potential analyzer, and (FESEM) field emission scanning electronic microscopy, were used to characterize (NGO) nano graphene oxide, synthesized by a modified Hummer's method. The (SPME) method solid phase micro extraction method employed to remove the trace elements (Mg, Co, Ni, Cu, Cd, and Pb) from cutting rock samples under the optimum conditions. The average concentrations of Magnesium, Cobalt, Nickel, Copper, Cadmium, and Lead, the average concentrations in cutting rock samples (direct technique) were (9.72 g/mL), (1.318 g/mL), (5.646 g/mL), (0.616 g/mL), (0.567 g/mL), and (9.296 g/mL). The average element concentrations by SPME technique (2.082 g/mL), (0.24 g/mL), (1.066 g/mL), (0.162 g/mL), (0.055 g/mL), and (2.153 g/mL) for Magnesium, Cobalt, Nickel, Copper, Cadmium, and Lead, respectively were decreased, confirming the chemical adsorption process on the (NGO) surface sheets.

A magnetic covalent organic framework as selective adsorbent for preconcentration of multi strobilurin fungicides in foods

A new method that utilizes a magnetic covalent organic framework (Fe3O4@BTA-TAPM) as a selective solid-phase extraction adsorbent has been developed for the simultaneous preconcentration of trace eleven kinds of strobilurin fungicides (SFs) in foods combined with ultra-high performance liquid chromatography-tandem mass spectrometry. The preconcentration conditions were optimized, including the adsorbent amount, extraction time, pH value, shaking time, elution solvent, desorption time and the interference ions. The maximum adsorption capacity of the adsorbent was ranging from 42.84 mg g−1 to 54.18 mg g−1 for eleven SFs. The low limits of detection were 0.003–0.072 μg kg−1. The recoveries of eleven SFs spiked at levels of 0.25–1000 μg kg−1 ranged from 80.2% to 109.3%, and the relative standard deviations were <6.8% (n = 3). The utility of the adsorbent was demonstrated to determine traces SFs in four different samples.

Preparation of a Novel Biocompatible Sorbent Based on Metal-Organic Frameworks Containing L-Menthol-Salicylic Acid Deep Eutectic Solvent for Pre-Concentration of Traces of Some Hazardous Heavy Metal Ions from Several Real Samples and Their Determination by Electrothermal Atomic Absorption Spectrometry

Preparation of a Novel Biocompatible Sorbent Based on Metal-Organic Frameworks Containing L-Menthol-Salicylic Acid Deep Eutectic Solvent for Pre-Concentration of Traces of Some Hazardous Heavy Metal Ions from Several Real Samples and Their Determination by Electrothermal Atomic Absorption Spectrometry

Front Cover: Application of a synthetic ligand in rapidly synergistic cloud point method for separation and preconcentration trace amounts of copper of water samples

DOI: 10.1002/sscp.202100029 The cover picture shows the use of the rapidly synergistic cloud point extraction method. The selection of a suitable ligand (here 4-BPDC) can lead to a low detection limit and good sensitivity in the UV/Vis spectrophotometry technique, which it is an advantage in addition to ease of operation, use of inexpensive materials and the easy access of this method for the determination of trace amounts of copper in water samples.

Application of a synthetic ligand in rapidly synergistic cloud point method for separation and preconcentration trace amounts of copper of water samples

AbstractIn this study, a rapidly synergistic cloud point extraction method was used to separate and pre‐concentrate small amounts of copper ions. Synthetic ligand 4‐benzylpyridine dithiocarbamate as a complexing agent, non‐ionic surfactant (Triton X‐100) as an extractant, and octanol as a synergic reagent were used. Parameters affecting copper ion extraction such as pH, ligand concentration, octanol volume, type of diluent solvent, stirring speed and time, surfactant concentration, and the effect of ionic strength were investigated. Ultraviolet‐visible spectrophotometry was used to measure the absorption of copper complex. Under optimal conditions, limit of detection, preconcentration factor, and relative standard deviation for copper were 1.4 × 10–3 μg /mL, 10 and 2.1, respectively. Also, the relative extraction efficiency of copper extraction in real samples was greater than 97%.

A centrifuge-less cloud point extraction-spectrophotometric determination of copper(II) using 6-hexyl-4-(2-thiazolylazo)resorcinol

A simple, cheap, and environmentally friendly centrifuge-less cloud point extraction procedure was developed for the preconcentration of traces of Cu(II) before its spectrophotometric determination. It is based on a complexation reaction with the hydrophobic azo reagent 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR), in which a complex with a stoichiometric ratio of 1:1 and an absorption maximum at 535 nm is formed. The experimental conditions for Cu(II) determination were found: HTAR concentration (8 × 10−6 mol mL−1), mass fraction of the surfactant Triton X-114 (2.2%), pH (5.9, ammonium acetate buffer), and incubation time (10 min at 60 °C). The linear range, limit of detection, molar absorption coefficient and preconcentration factor were calculated to be 4.5–254 ng mL−1, 1.34 ng mL−1, 2.54 × 105 L mol−1 cm−1, and 10, respectively. The effect of foreign ions was studied, and the proposed procedure was applied to the analysis of water samples and a saline solution for intravenous infusion.

Application of HKUST‐1 metal‐organic framework as coating for headspace solid‐phase microextraction of some addictive drugs

In the present study, a copper-based metal-organic framework (HKUST-1) was used first time for preconcentration trace amounts of addictive drugs in biological samples. HKUST-1 was synthesized and coated onto the surface of stainless steel wire. The prepared coating was used in headspace solid-phase microextraction method coupled with gas chromatography-mass spectrometry for preconcentration and determination of some addictive drugs in biological fluids. Prepared coating shows good extraction efficiency due to large surface area, and π-π stacking interaction with selected analytes. Under optimum conditions, the method was validated with a reasonable determination coefficient (R2 >0.9961) and suitable linear dynamic range (0.5-1000μgL-1 ). Also, the limits of detections were obtained in the range of 0.1-0.4, 0.2-0.6, and 0.4-0.7μgL-1 for water, urine, and plasma samples, respectively. The limits of quantification of present method were obtained in the range 0.5-1.3, 0.7-1.5, and 1.0-1.9μgL-1 in water, urine, and plasma samples, respectively. The intra-day and inter-dye single fiber and fiber to fiber relative standard deviations were observed in the range 3.0-13.9% and 3.5-12.3%, respectively. Finally, the present method was applied for the determination of the drugs in biological samples.

An environmentally friendly cloud point extraction–spectrophotometric determination of trace vanadium using a novel reagent

A simple, low-cost, and green cloud point extraction (CPE) procedure was developed for the preconcentration of traces of vanadium as a preliminary step for its spectrophotometric determination. Vanadium(V) was complexed with H2O2 and a novel commercially available reagent, 6-hexyl-4-(2-thiazolylazo)-resorcinol (HTAR), which was preliminary investigated by both theoretical (B3LYP/6-311++G**) and experimental approaches. The ternary complex was then extracted into a small volume of a surfactant-rich phase (Triton X-100). The experimental conditions for total vanadium determination, optimized by the one‐factor‐at‐a‐time method, were found: H2O2 concentration (1.8 × 10−4 mol L−1), HTAR concentration (6.4 × 10−5 mol L−1), acidity (7 × 10−3 mol L−1 H2SO4), mass fraction of the surfactant (2%), incubation time (25 min) and wavelength (582 nm). The linear range, limit of detection, molar absorption coefficient and enrichment factor were calculated to be 2.6–510 ng mL−1, 0.8 ng mL−1, 1.66 × 105 L mol−1 cm−1, and 10.4, respectively. The composition of the extracted complex was V:HTAR:O22− = 1:1:2, which corresponds to a formula [VV(HL)(O2)2], where HL− is the monoprotonated HTAR. The effect of foreign ions was studied, and the accuracy of the proposed procedure was verified by an analysis of an environmental matrix reference material (TM-15.3; Canadian fortified lake water containing 14.2 ng mL−1 of vanadium) and spent silica-supported catalysts. The “greenness” of the developed method was evaluated using the Green Analytical Procedure Index (GAPI).

Preparation of a novel amino functionalized ion-imprinted hybrid monolithic column for the selective extraction of trace copper followed by ICP-MS detection

In this work, a novel amino functionalized Cu(II) ion-imprinted organic-inorganic hybrid monolithic column (Cu(II)-IIHMC) was prepared via one-pot co-condensation and the combination of sol-gel and ion-imprinting techniques in a fused capillary. The Cu(II)-IIHMC was used as solid phase microextraction (SPME) matrix followed by inductively coupled plasma-mass spectrometry (ICP-MS) for the analysis of trace Cu(II). The prepared Cu(II)-IIHMC has good mechanical strength, stable imprinting sites and homogeneous structure of network skeleton with large flow-through pores by optimizing the synthesis process. Under the optimized conditions, the Cu(II)-IIHMC can selectively adsorb Cu(II) with the adsorption capacity of 3.13 mg g−1. With enrichment factor of 10-fold, the calibration curve was established in the range of 0.05–50 μg L−1 with r2 of 0.9992 and the detection limit was 0.008 μg L−1 for Cu(II). Compared with the non-imprinted hybrid monolithic column (Cu(II)-NIHMC), the Cu(II)-IIHMC possesses better selectivity, anti-interference ability and adsorption capacity. The Cu(II)-IIHMC can specifically capture the target ion in the presence of competitive ions, with the selectivity coefficients exceeding 39.4. The protocol was validated by analyzing Certified Reference Materials of standard sediment, soil and iron ore, and the results were in good agreement with certified values. Moreover, the proposed in-tube SPME procedure can not only preconcentrate trace Cu(II), but also effectively reduce the matrix effect and powerfully eliminate the interference from the main metals in real samples. Therefore, the developed SPME-ICP-MS method with facile preparation, specific selectivity, high sensitivity and efficient analysis, was applied in the determination of trace Cu(II) in environmental and mineral samples with the recoveries of 89.8–111.8% in all spiked samples.

Magnetic Fe3O4@Mg/Al-layered double hydroxide adsorbent for preconcentration of trace metals in water matrices

A magnetic Fe3O4@MgAl-layered double hydroxide (MLDH) nanocomposite was successfully synthesized and applied as an effective adsorbent for preconcentration of trace As(III), Cd(II), Cr(III), Co(II), Ni(II), and Pb(II) ions from complex matrices. The quantification of the analytes was achieved using the inductively coupled plasma optical emission spectrometry (ICP-OES) technique. The nanocomposite was then characterized using BET, FTIR, SEM, and EDS. Due to its high adsorption surface area, compared to traditional metal oxide-based adsorbents, MLDH nanocomposite exhibited high extraction efficiency. Several experimental parameters controlling the preconcentration of the trace metals were optimized using response surface methodology based on central composite design. Under optimum conditions, the linearity ranged from 0.1 to 500 µg L−1 and the correlation of coefficients (R2) were higher than 0.999. The limits of detection (LODs) and quantification (LOQs) were 0.11–0.22 µg L−1 and 0.35–0.73 µg L−1, respectively. The intra-day (n = 10) and inter-day precisions (n = 5 working days) expressed in the form of percent relative standard deviations (%RSDs) were below 5%. The proposed method was successfully applied for the analysis of the As(III), Cd(II), Cr(III), Co(II), Ni(II), and Pb(II) ions in different environmental water samples.

Preconcentration and separation of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) in environmental samples on cellulose nitrate membrane filter prior to their flame atomic absorption spectroscopy determinations

ABSTRACT A new and sensitive enrichment membrane filtration method was applied for the preconcentration and separation of trace amounts of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) ions from environmental (water and food) samples prior to their flame atomic absorption spectrometric (FAAS) determinations. The method was based on the collection of analyte ions as quinalizarin complexes on cellulose nitrate membrane filter and then eluted using nitric acid. The concentration levels of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) ions in the final solutions were determined by FAAS. Various analytical parameters which affect the collection and determination of metal ions including pH, amounts of quinalizarin, sample volume, type and size of the membrane filter, flow rates and matrix effects were investigated. The analyte ions recovery values were measured and found to be in the range of 95–101%. The relative standard deviation (RSD%) was measured to determine the precision of the proposed approach and was found to be ≤5.0%. The detection limits for the proposed method were in the range of 0.1–0.7 μg L−1. The preconcentration factors were 100 and 125 for (Cd(II), Co(II), Cu(II) and Ni(II)) and Pb(II), respectively. The validation of the proposed method was verified by the analysis of certified reference materials. Satisfactory results for separation and preconcentration trace levels of the analyte ions in water and food samples.

A new carrier element-free coprecipitation method with 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-thiol for separation, preconcentration, and determination of some metal ions in water and food samples

ABSTRACT A new, simple, and accurate carrier element-free coprecipitation method has been developed to separate and preconcentrate of Cd(II), Cu(II), Ni(II), and Pb(II) ions from water and food samples. The proposed method was based on utilisation of 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-thiol (BNBATT) as a new organic co-precipitant at pH 7.0 and the determination of the metal ions being examined using FAAS. To recover the metal ions analysed, The influencce of many parameters including pH, sample volume, co-precipitant quantity, and the rate and time of centrifugation, was tested. There was also monitoring the effect of matrix ions, and no interferences were found. The validity of the proposed method was verified by test of certified reference materials. The analyte ions recovery values were measured and found to be in the range of 95–100%. The relative standard deviation (RSD%) was measured to determine the precision of the proposed approach and was found to be ≤ 5.0%. The limits of detection (K = 3.0, N = 10), were determined in the range of 0.3–0.8 μg L−1. The calculated preconcentration factor was 100 for Cd(II), Cu(II) and Ni(II) and 80 for Pb(II). Satisfactory results for separation and preconcentration trace amounts of the studied metal ions in water, food, and certified reference materials samples.

Efficient pre-concentration of As(III) in food samples using guanidine-modified magnetic mesoporous silica

An efficient magnetic mesoporous structure was designed and prepared for the facile pre-concentration of As(III) ions. To prepare the sorbent, core–shell magnetic silica nanoparticles were covered by MCM-41 like structure and then the surface was modified by guanidine via an amine linker (GA-MSMP). The prepared adsorbent was investigated as an effective and sensitive material for the adsorption of arsenic ions from the aqueous solution by applying a normal batch method. The imperative variables of the adsorption were studied to increase efficiency. The dynamic and static processes were tested that matched a pseudo-second-order of kinetic model and the Langmuir isotherm model, respectively. The sorbent reusability was investigated and it was confirmed that the designed product could be applied at best for six cycles successively without any significant efficiency losing. The synthesized product was tested to determine and pre-concentrate trace amounts of arsenic ions in rice and natural waters as a real sample. A desorption process applying 5 mL of hydrochloric acid (0.5 mol L−1) as an eluent, exhibited about 98% recovery of the As(III) ions adsorbed on the GA-MSMP sorbent. The maximum adsorption capacity of the GA-MSMP was calculated to be 312 mg g−1 for adsorption of As(III) under the optimal conditions.

The in situ technique of aqueous binding concentration and diffusion for measurements of arsenate concentrations in lake waters

Arsenic contaminations in waters are concerned worldwide. This research was to examine an in situ method of aqueous binding concentration and diffusion (ABCD) technique with an aqueous solution of metal immobilized polycationic polymer (MIP) as a binding phase and a dialysis membrane as a diffusive layer to pre-concentrate trace arsenate in lake waters. Although the maximum binding capacity of arsenate to MIP was influenced by the presence of anions in water, the binding phase was capable of pre-concentrating arsenate in lake water. This in situ pre-concentration technique was combined with light emitting diodes (LED) for semi-on line detection of trace arsenate in waters. The system was eventually validated in lake waters in lab and in natural lake waters in China.In this work, new colorimetric method for detection of arsenate in the binding phase has been developed to minimize the potential spectra interferences of silicates, phosphates and other oxyanions. Potassium iodide was used to reduce arsenate to arsenite before the solution was mixed with the colour generation reagent of RhodamineB.

Sorption Preconcentration Of Silver For Atomic Absorption Analysis And Antibacterial Properties Of The Acid-Modified Clinoptilolite – Ag Composite

Sorptive properties of the acid-modified Transcarpathian clinoptilolite towards Ag(I) were studied under dynamic conditions. It was found that the most effective acid-modifier is 1 M HNO3 solution. The sorption capacity value of H-clinoptilolite under the optimal conditions is 6.15 mg of Ag per 1 g of zeolite. The solid-phase extraction procedure with acid-modified clinoptilolite was used to pre-concentrate trace amounts of silver ions in aqueous solutions and then finally to determine them by the atomic absorption method. Due to the acceptable recoveries (≥ 98 %) and RSD values (2.3-4.7 %) for tap and lake water, the developed method can be successfully applied for the determination of trace amounts of silver ions in the presence of major components of water. It was established that the initial form of clinoptilolite has a better antibacterial effect against E. coli than the H-form. However, antagonistic activity against S. aureus was lower than against E. coli in both forms. The combination of different forms of clinoptilolite with Ag(I) increases their antibacterial activity.

Mesoporous graphitic carbon nitride@NiCo2O4 nanocomposite as a solid phase microextraction coating for sensitive determination of environmental pollutants in human serum samples.

We report a facile hydrothermal method to synthesize a novel mesoporous graphitic carbon nitride (MCN)@NiCo2O4 nanocomposite, which can be used as a solid phase microextraction coating for high efficiency extraction and preconcentration of trace polychlorinated biphenyls and polycyclic aromatic hydrocarbons in human serum samples.