Aluminum Fluoride Complexes Research Articles

Formation of Aluminum-Fluoride Complexes Compromises Defluoridation Efficiency of Aluminum-Based Coagulation.

Aluminum-based coagulation has long been regarded as a reliable and cost-effective process for the defluoridation of industrial effluents. However, such a well-recognized viewpoint is challenged by the underestimation of fluoride levels in treated effluents. Herein, we developed a systematic protocol to distinguish different fluoride species, including free F-, exchangeable fluoride (EF), and nonexchangeable fluoride (NEF). We demonstrated that EF forms complexes with octahedral aluminum (AlO6) on the surface of polyaluminum and can be exchanged with (1,2-cyclohexylenedinitrilo)-tetraacetic acid (CDTA). However, NEF is incorporated with tetrahedral aluminum (AlO4) at the core of polyaluminum, as confirmed by 19F/23Al NMR and ESI-MS analysis, and cannot be exchanged with CDTA due to steric hindrance. Increasing the aluminum coagulant dosage effectively reduced free F- levels in photovoltaic and electroplating effluents to below 1 mg/L. However, the total fluoride content, with over half in the form of EF and NEF, was above 2 mg/L, exceeding the discharge limit regulated by many local governments of China. Furthermore, both EF and NEF can gradually transform to free F- in natural waters. Our findings indicate that aluminum-based coagulation inevitably accompanies the formation of substantial amounts of EF and NEF, compromising its defluoridation efficiency toward industrial effluents.

Investigating the Mechanism of Aluminum Fluoride Chelation.

Aluminum fluoride (AlF) complexes have been used over the past decade to incorporate [18F]fluoride into large biomolecules in a highly selective fashion by using relatively facile conditions. However, despite their widespread usage, there are a large number of variations in the reaction conditions, without a definitive discussion provided on the mechanism to understand how these changes would alter the end result. Herein, we report a detailed mechanistic investigation of the reaction, using a mixture of theoretical studies, fluorine-19 and fluorine-18 chemistry, and the consequences it has on the efficient clinical translation of AlF-containing imaging agents.

Utilisation of a dianionic pentadentate ligand in group 13 chemistry

Using the pentadentate tetrapyrazolylpyridyl diborate (B2Pz4Py) ligand allowed for the isolation of overall seven group 13 complexes, which have been fully characterised and whose solid-state structures were obtained by single-crystal X-ray diffraction analysis. The aluminium chloride (1) and bromide (2) complexes as well as the gallium chloride (3) and iodide (4) complexes are accessible by deprotonation of the ligand precursors [B2Pz4LiPyH]2 with lithium hexamethyldisilazide and subsequent reaction with aluminium and gallium trihalides. Using indium(I) chloride instead gives rise to the indium(III) bis(trimethylsily)amide complex 5. Chloride abstraction from the aluminium(III) complex 1 using a combination of TlBArF24 and TlPF6 affords the related aluminium(III) fluoride complex 6 while using the gallium(III) complex 3 yields the dinuclear cationic PF2O2-bridged gallium(III) complex 7.

Spectrophotometric Determination of Fe(II) and Fe(III) Using 5-(4-Ethylphenyl azo ) 2-Hydroxybenzaldehyde Oxime Reagent

Spectrophotometric Determination of Fe(II) and Fe(III) Using 5-(4-Ethylphenyl azo ) 2-Hydroxybenzaldehyde Oxime Reagent

18F-labeled tracers targeting fibroblast activation protein

BackgroundCancer-associated fibroblasts are found in the stroma of epithelial tumors. They are characterized by overexpression of the fibroblast activation protein (FAP), a serine protease which was already proven as attractive target for chelator-based theranostics. Unfortunately, the value of gallium-68 labeled tracers is limited by their batch size and the short nuclide half-life. To overcome this drawback, radiolabeling with aluminum fluoride complexes and 6-fluoronicotinamide derivatives of the longer-lived nuclide fluorine-18 was established. The novel compounds were tested for their FAP-specific binding affinity. Uptake and binding competition were studied in vitro using FAP expressing HT-1080 cells. HEK cells transfected with the closely related dipeptidyl peptidase-4 (HEK-CD26) were used as negative control. Small animal positron emission tomography imaging and biodistribution experiments were performed in HT-1080-FAP xenografted nude mice. [18F]AlF-FAPI-74 was selected for PET/CT imaging in a non-small cell lung cancer (NSCLC) patient.ResultsIn vitro, 18F-labeled FAPI-derivatives demonstrated high affinity (EC50 = < 1 nm to 4.2 nm) and binding of up to 80% to the FAP-expressing HT1080 cells while no binding to HEK-CD26 cells was observed. While small animal PET imaging revealed unfavorable biliary excretion of most of the 18F-labeled compounds, the NOTA bearing compounds [18F]AlF-FAPI-74 and -75 achieved good tumor-to-background ratios, as a result of their preferred renal excretion. These two compounds showed the highest tumor accumulation in PET imaging. The organ distribution values of [18F]AlF-FAPI-74 were in accordance with the small animal PET imaging results. Due to its less complex synthesis, fast clearance and low background values, [18F]AlF-FAPI-74 was chosen for clinical imaging. PET/CT of a patient with metastasized non-small cell lung cancer (NSCLC), enabled visualization of the primary tumor and its metastases at the hepatic portal and in several bones. This was accompanied by a rapid clearance from the blood pool and low background in healthy organs.Conclusion[18F]AlF-labeled FAPI derivatives represent powerful tracers for PET. Owing to an excellent performance in PET imaging, FAPI-74 can be regarded as a promising precursor for [18F]AlF-based FAP-imaging.

Indirect determination of aluminum (III) in water samples by in-electrode coulometric titration

A new procedure has been developed for indirect determination of aluminium(III) in water through in-electrode coulometric titration in a porous reticulated vitreous carbon electrode. It was determined through different aluminium fluoride and ferric fluoride complex stabilities. The ferric fluoride complex thereby formed was decomposed with Al(III) from the sample and an aliquot of the released Fe(III) was determined electrochemically. It was measured with an EcaFlow GLP 150 electrochemical flow analyser, while 0.2 mol L−1 sodium chloride solution was used as the electrolyte to flush the system. Calibration solutions and samples were modified in a mixed solution medium of 0.2 mol L−1 NaCl + 10 mg L−1F(I-) + 10 mg L−1Fe(III). All working parameters for electrochemical determination were optimised. The detection limit and precision were found to be 0.02 mg L−1 and 1.9% respectively. The linear concentration range was 0.05 – 8.5 mg L−1 of aluminium. After having been complexed with sodium cyanide, the iron’s interference effect was suppressed by removing it with an ion-exchange resin. Among the other influences studied, only the interference from thorium, zirconium and cerium was significant. The method was applied for the analysis of various water samples. The results were in good agreement with data from high resolution atomic absorption spectrometry.

Application of microextraction techniques for indirect spectrophotometric determination of fluorides in river waters

The present study is dedicated to development of improved method for determination of trace amounts of fluorides in natural waters which is based on the interaction of fluorides with ion associate (IA) of Al(III), salicylic aldehyde acylhydrazones (benzhydrazone (SABH) and 4-picolinhydrazone (SAPH)) and polymethine dye Astra Phloxine FF (AP). Comparison of analytical forms [Al(SABH)2]⋅AP and [Al(SAPH)2]⋅AP showed that the analytical system Al(III)-SAPH-AP is more effective, namely, a higher level of preconcentration of the analytical form is ensured by and extraction equilibrium is achieved faster. Based on the study, we propose a new, fast, simple, reliable, sensitive, and accurate method of the indirect UV–Vis-spectrophotometric determination of fluorides grounded on the interaction of fluorides with IA of Al(III), SAPH and AP with the utilization of vortex-assisted liquid-liquid microextraction (VALLME). The method is based on the discoloration of the microextract of IA of Al(III), SAPH and AP (Al-SAPH-AP) in presence of fluoride ions due to the formation of fluoride complexes of aluminum with higher stability. The effect of various factors has been studied. The optimal conditions of the UV–Vis-spectrophotometric determination of fluorides were defined as: pH 7.0–10.0, 1.0⋅10−6 mol⋅L−1 Al(III); 4.0⋅10−5 mol⋅L−1 SAPH; 1.0⋅10−6 mol⋅L−1 AP; λ = 560 nm. VALLME have been carried out in 250 μL of CCl4 at 20:1 vol ratios of aqueous and organic phases, with vortexing at 3000 rpm for 15 s followed by centrifugation at 2000 rpm for 2 min. The determination of fluorides is feasible in the presence of various interferences. The calibration curve shows the linear dependence in the range of 0.3–114 μg⋅L−1 of the fluorides concentration (R2 = 0.993) with the limit of detection of 0.086 μg⋅L−1 and the limit of determination of 0.284 μg⋅L−1. The accuracy of the proposed protocol of fluorides determination was verified towards a reference method on the samples of natural rivers waters (RSD 2.6–3.1%, recovery 98.3–101.4%).

Thiol-Reactive PODS-Bearing Bifunctional Chelators for the Development of EGFR-Targeting [18F]AlF-Affibody Conjugates.

Site-selective bioconjugation of cysteine-containing peptides and proteins is currently achieved via a maleimide–thiol reaction (Michael addition). When maleimide-functionalized chelators are used and the resulting bioconjugates are subsequently radiolabeled, instability has been observed both during radiosynthesis and post-injection in vivo, reducing radiochemical yield and negatively impacting performance. Recently, a phenyloxadiazolyl methylsulfone derivative (PODS) was proposed as an alternative to maleimide for the site-selective conjugation and radiolabeling of proteins, demonstrating improved in vitro stability and in vivo performance. Therefore, we have synthesized two novel PODS-bearing bifunctional chelators (NOTA-PODS and NODAGA-PODS) and attached them to the EGFR-targeting affibody molecule ZEGFR:03115. After radiolabeling with the aluminum fluoride complex ([18F]AlF), both conjugates showed good stability in murine serum. When injected in high EGFR-expressing tumor-bearing mice, [18F]AlF-NOTA-PODS-ZEGFR:03115 and [18F]AlF-NODAGA-PODS-ZEGFR:03115 showed similar pharmacokinetics and a specific tumor uptake of 14.1 ± 5.3% and 16.7 ± 4.5% ID/g at 1 h post-injection, respectively. The current results are encouraging for using PODS as an alternative to maleimide-based thiol-selective bioconjugation reactions.

Effects of post bonding annealing on GaAs//Si bonding interfaces and its application for sacrificial-layer-etching based multijunction solar cells

By using the sacrificial layer (SL) etching, GaAs substrates are separated from III–V epi substrate//Si substrate junctions that are made by surface activated bonding (SAB) technologies. The post-bonding low-temperature (300-∘C) annealing plays an essential role in achieving a promising (∼90%) bonding yield. The effects of the post-bonding annealing are investigated by hard X-ray photoemission spectroscopy and current–voltage measurements of GaAs//Si bonding interfaces. It is found that the concentration of oxygen atoms at interfaces is reduced and the resistance decreases to 1.6–2.1 mΩcm2 by the low-temperature annealing. Aluminum fluoride complexes are not observed by X-ray photoelectron spectroscopy on the exposed surfaces of separated GaAs substrates. The roughness average of the surfaces is ≈0.25–0.30 nm. The characteristics of double junction cells fabricated on the GaAs//Si junctions prepared by the SL etching are almost the same as those of cells fabricated by dissolving GaAs substrates after bonding. These results indicate that multijunction cells could be fabricated in a process sequence compatible with reuse of GaAs substrates by combining the SL etching and SAB.

Tea components influencing bioavailability of fluoride and potential transport mechanism in the Caco‐2 cell line model

SummaryPrevious work showed that the bioavailability of fluoride in dark tea was lower than NaF solution. However, limited information is available indicating the effects of tea components on the fluoride bioavailability. In this study, the effects of the components in tea on the bioavailability of fluoride were evaluated in the Caco‐2 cell line model. Additionally, the mechanism of effect of aluminium on fluoride transport was investigated. The result showed that 10–100 μm of epigallocatechin gallate (EGCG) could not influence fluoride transport. Al3+ significantly decreased fluoride transport in both apical‐basolateral and basolateral‐apical directions. Moreover, aluminium could form different forms of aluminium fluoride complexes, which were transported through Caco‐2 cells by different pathways. F− transport was mainly dependent on the paracellular pathway and active transport involving Cl− channels. The paracellular pathway played a predominant role in transport of AlF3. The paracellular pathway and active transport both participated in AlF2+ transport.

Preliminary investigation of aluminium fluoride complexes in aqueous solutions with capillary electrophoresis coupled with electrospray ionization mass spectrometry and with inductively coupled plasma mass spectrometry.

It is crucial to identify and confirm the original species of aluminium ions (Al3+ ) dissolved in water, since they behave differently. Depending on their species, the toxicity differs. Capillary electrophoresis (CE) coupled with electrospray ionization mass spectrometry (ESI-MS) and CE coupled with inductively coupled plasma mass spectrometry (CE/ICP-MS) were explored to identify and determine simple systems of Al species solutions at pH 3.0. The new combinations of techniques, namely, ESI-MS coupled with CE for identification of species and ICP-MS coupled with CE for confirmation, were applied to for the analyses of Al and fluoride (F) solutions. Al monomers, some Al dimers and trimers were detected by CE/ESI-MS. CE/ICP-MS experiments were conducted with the assembled interface. As a result, the calibration line showed R2 = 0.9856, and the detection limits were 35 nL and 0.037 μM. The results were compared with data obtained using MINEQL+. Most of the Al species detected were monomers; some dimers and trimers were detected by CE/ESI-MS, but they were not detected by CE-ICP-MS, probably owing to extremely low concentrations. The Al speciation technique was improved by CE/ESI-MS, and the Al species present at extremely low concentrations were ascertained by CE/ICP-MS. The use of coupled instruments will be one of the most powerful tools for identifying dissolved metal ions.

Preparation and Properties of an Aluminum Hydroxide-Modified Diatomite Sorbent for Removal of Fluorides from Waters

A new sorbent (Al-D) for the removal of fluoride ions is prepared by modifying diatomite with aluminum ions. The sorbent is studied using X-ray diffraction, thermogravimetry, X-ray photoelectron spectroscopy, and adsorption structure analysis; its ability to remove fluoride ions from model aqueous solutions is measured under static conditions. The diatomite, which is modified by heterogeneous hydrolysis of an aluminum salt in the presence of diatomite suspension, has a higher specific surface area and a greater sorption pore volume and exhibits excellent characteristics in fluoride adsorption. Fluoride sorption isotherms measured under equilibrium conditions are modeled using the Langmuir, Freundlich, Langmuir−Freundlich, Brunauer−Emmett−Teller, and two-step Langmuir equations. The model parameters are calculated. The two-step Langmuir model gives the best fit to the experimental isotherms (R2 = 0.9836). Fluoride adsorption on the sorbent Al-D occurs via ion exchange: surface OH− groups are replaced with fluoride ions from solution to form aluminum fluoride complexes at the sorbent surface.

Identification of aluminum fluoride complex in the absorber of a desulfurization system

Electric power plants generate energy, but by products in the form of small particles of waste which contain high quantities of sulfides are also produced. Regional law prohibits the expulsion of sulfur into the atmosphere. Because sulfurous acid gas (SO2) becomes concentrated in power plant furnaces owing to the recirculation of flue gas, optimal conditions for efficient sulfation are required. In conventional coal combustion, the indirect sulfation of limestone occurs. The sulfation efficiency in conventional coal combustion is usually low because of sintering of the absorber. Usually preserving values for optimal conditions are set and plant operation is maintained at 100%, but sometimes a 1 or 2% decrease in activity occurs. When [Al]3+ = 0.4 mM and [F]− = 4 mM at pH 5.5, the concentration of [AlF4]− is higher than that of [AlF3]. Under these conditions in the absorber, [AlF4]− is considered to increase in quantity and to form a complex with Ca2+ from limestone. When the pH of the absorber increases, [AlF3] and [AlF4]− decrease and [F]− increases. It is concluded that the concentration of [AlF4]− governs the decrease in activity in the absorber. In the spectra of electrospray ionization mass spectrometry (ESI-MS), five peaks were observed and assigned to CaSO4+ AlF4−, 2CaCO3+ AlF4−, 2CaCO3 + CaF2 + AlF4−, 2CaCO3 + CaSO4 + H2O + AlF4−, and 2CaCO3 + CaF2 + CaSO4 + H2O + AlF4− from the chemical components in the actual absorber.

Interactions between different acids and bauxitic-based ceramic proppants used in gravel-packed and fractured wells

Proppants are widely used in hydraulic fracturing operations. They consist of solid particles with specific strengths and are used to keep the fractures open to enhance well production. They can be natural sand or artificial ceramic materials. Most ceramic proppants are alumina-based, using kaolin and bauxitic clays as the raw materials. The acid resistance of the fracturing proppant is an essential property. Acids are sometimes needed to clean the fracture by removing scale and clays that reduce the fracture conductivity.In this study, several experiments were conducted using a see-through cell, and an aging cell with 10 wt% HCl, mud acids (6.0 wt% HCl, 1.0 wt% HF and 12.0 wt% HCl, 3.0 wt% HF), i.e., (6:1 and 12:3), and formic (HCOOH), trisodium salt of N-(hydroxyethyl)-ethylenediaminetriacetic acid (Na3-HEDTA) and HF mixtures up to 350 °F. The effects of varying acid system, temperature, soaking time, static and dynamic conditions were examined. The supernatant of solubility tests was analyzed with Fluorine Nuclear Magnetic Resonance (19F NMR) to identify the reaction products. Key elements concentrations were measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). A Zeiss Axiophot microscope was used to acquire images for the proppant particles to study particle shape and effect of acid solubility. Proppants were then analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The proppant was sieved before and after the experiments. The residual solids were dried and analyzed using a scanning electron microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) capabilities. Effects of acid dissolution on mechanical performance of the proppants were also tested using an automated load frame.The results show that bauxite has a minimal solubility of 0.5 wt% in 10.0 wt% HCl. The proppant is readily soluble in different mud acids, 56.0 wt% dissolved in some cases. The amount dissolved increases with temperature, soaking time, acid concentration, and dynamic conditions. The fines generated and the changes in grain size distribution are detrimental to the proppant conductivity. 19F NMR showed aluminum fluoride complexes with different mud acids due to the high Al/F affinity. XRF showed that the solubility of the proppant occurs mainly in mullite and maghemite due to their high reactivity. Crush resistance test shows a direct relationship between solubility and mechanical strength of bauxite. Assessing solubility effects will help to better design acid treatments without jeopardizing the integrity of the proppant.

Fluoride removal by Al, Ti, and Fe hydroxides and coexisting ion effect

Batch experiments were conducted to evaluate fluoride removal by Al, Fe, and Ti-based coagulants and adsorbents, as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal by co-precipitation with alum (Al2(SO4)3·18H2O). Aluminum sulfate was more efficient than the other coagulants for fluoride removal in the pH range between 6 and 8. Nano-crystalline TiO2 was more effective for fluoride removal than Al and Fe hydroxides in a pH range of 3–5. Coexisting anions in water decreased the removal of fluoride in the order: phosphate (2.5mg/L)>arsenate (0.1mg/L)>bicarbonate (200mg/L)>sulfate (100mg/L)=nitrate (100mg/L)>silicate (10mg/L) at a pH of 6.0. The effect of silicate became more significant at pH>7.0. Calcium and magnesium improved the removal of fluoride. Zeta-potential measurements determined that the adsorption of fluoride shifted the PZC of Al(OH)3 precipitates from 8.9 to 8.4, indicating the chemical adsorption of fluoride at the surface. The presence of fluoride in solution significantly increased the soluble aluminum concentration at pH<6.5. A Visual MINTEQ modeling study indicated that the increased aluminum solubility was caused by the formation of AlF2+, AlF2+, and AlF3 complexes. The AlFx complexes decreased the removal of fluoride during co-precipitation with aluminum sulfate.

Speciation analysis of aluminium in plant parts of Betula pendula and in soil

The research presents the first results of aluminium speciation analysis in aqueous extracts of individual plant parts of Betula pendula and soil samples, using High Performance Ion Chromatography with Diode Array Detection (HPIC-DAD). The applied method allowed us to carry out a full speciation analysis of aluminium in the form of predominant aluminium–fluoride complexes: AlF(x=2,3,4)(3−x) (first analytical signal), AlF2+ (second analytical signal) and Al3+ (third analytical signal) in samples of lateral roots, tap roots, twigs, stem, leaf and soil collected under roots of B. pendula. Concentrations of aluminium and its complexes were determined for two types of environment characterised by different degree of human impact: contaminated site of the Chemical Plant in Luboń and protected area of the Wielkopolski National Park. For all the analysed samples of B. pendula and soil, AlF(x=2,3,4)(3−x) had the largest contribution, followed by Al3+ and AlF2+. Significant differences in concentration and contribution of Al–F complexes and Al3+ form, depending on the place of sampling (different anthropogenic pressure) and plant part of B. pendula were observed. Based on the obtained results, it was found that transport of aluminium is “blocked” by lateral roots, and is closely related to Al content of soil.

An Aluminum Fluoride Complex with an Appended Ammonium Salt as an Exceptionally Active Cooperative Catalyst for the Asymmetric Carboxycyanation of Aldehydes.

Al-F bonds are among the most stable σ bonds known, exhibiting an even higher bond energy than Si-F bonds. Despite a stability advantage and a potentially high Lewis acidity of Al-F complexes, they have not been described as structurally defined catalysts for enantioselective reactions. We show that Al-F salen complexes with appended ammonium moieties give exceptional catalytic activity in asymmetric carboxycyanations. In addition to aromatic aldehydes, enal and aliphatic substrates are well accepted. Turnover numbers up to around 104 were achieved, whereas with previous catalysts 101 -102 turnovers were typically attained. In contrast to Al-Me and Al-Cl salen complexes, the analogous Al-F species are remarkably stable towards air, water, and heat, and can be recovered unchanged after catalysis. They possess a considerably increased Lewis acidity as shown by DFT calculations.

Aluminum Activity in Alpine Tundra Soil, Rocky Mountain National Park, Colorado, U.S.A.

Shifts in seasonal aluminum (Al) activity and speciation in poorly buffered alpine tundra soil, attributable to atmospheric deposition of reactive nitrogen, can result in increased Al bioavailability, adversely impacting high-altitude plant and microbial communities. To evaluate seasonal changes in Al soil solution chemistry, intact soil column leaching studies were conducted to determine pore water Al speciation and transport under saturated spring melt-off conditions and unsaturated late summer conditions. These results were compared with aqueous Al speciation in surface and groundwater seep samples collected during the June to August growing season. Analysis of soil column leachates, surface and groundwater seep samples, indicated that Al activity was controlled by the aluminum hydroxyl sulfate suite of minerals, jurbanite, basaluminite, and alunite. Soil pore water collected from saturated soil cores consisted primarily of aluminum fluoride (Al-F) complexes for pore volumes (PV) < 5.0, with aluminum hydroxyl (Al-OH) complexation increasing with continued elution. Leachates collected from unsaturated soil cores exhibited Al-F transport only within the soil wetting front, PV < 1.0, after which, Al-OH complexes were predominant. The presence of fluoride (F−) in the soil pore water in the reactive solution front resulted in notable shifts between Al controlling solid phases and aqueous speciation. Similar shifts in Al speciation and controlling Al solid phases were observed in surface and groundwater seep samples, with sampling date and elevation. Results suggest that Al speciation and transport within alpine tundra soil may be seasonally influenced by soil moisture content and F− release from soil solid phases within the O/A1 soil horizons.

Fluoride removal from Double Leached Waelz Oxide leach solutions as alternative feeds to Zinc Calcine leaching liquors in the electrolytic zinc production process

The most important limitation of leached Waelz Oxide from the pyrometallurgical treatment of Electric Arc Furnace Dust (EAFD) is its high fluorine content. This work deals with the reduction of the harmful effects of the Double Leached Waelz Oxide fluorine content in the hydrometallurgical process for electrolytic zinc production process when it is used as raw material directly in the leaching stage. The resulting process is a purification treatment of Double Leached Waelz Oxide leach solution to remove the dissolved fluoride in this unpurified zinc liquor. Leached fluorides from this liquor are precipitated in order to reduce their concentration until the specified values, avoiding cathode corrosion in the electrowinning cells. In this paper a selective precipitation process to maximize the fluoride removal and to minimize the zinc losses is presented, achieving the industrially specified solution composition when the Zinc Calcine is the used raw material. The formation of aluminium-fluoride complexes and the variation of their solubilities with the pH evolution are the basis of the proposed treatment. In addition, this fluoride removal has also been improved and optimized in order to be integrated in the overall industrial hydrometallurgical process and the obtained results are presented and discussed proving the viability of this improved stage.

Application of a new HPLC-ICP-MS method for simultaneous determination of Al(3+) and aluminium fluoride complexes.

The paper presents the new HPLC-ICP-MS method used for conducting speciation analysis of aluminum as free Al3+ and aluminum fluoride complexes during one analysis. In the study, 5% HNO3 was used as a derivative reagent in order to minimize the possibility of clogging the torch in ICP-MS. Using the new HPLC-ICP-MS method, speciation analysis of aluminum and aluminum fluoride complexes was conducted on the basis of model solutions and real samples (soil-water extracts and groundwater samples). The analysis in the presented analytical system lasts only 4 min.