Precipitation Method Research Articles

In-situ forming Cu-based metal-organic framework in the presence of chitosan-Fe3O4 nanohybrids: A pH-sensitive carrier for controlled release of doxorubicin

In recent years, stimuli-responsive drug delivery systems based on pH, particularly those developed using bio-derived nanocomposite systems, have gained significant attention. In this work, a novel magnetic carrier was designed based on biopolymeric chitosan and metal-organic framework (MOF) for pH-controlling the release of anticancer drugs. To end this, an in-situ green method was performed to form Cu-based MOF in the presence of a magnetic polysaccharide synthesized by precipitation method toward the construction of CS/Fe3O4/Cu-MOF nanocomposite. The nanocomposite was immersed in an aqueous solution of a model anticancer drug, doxorubicin (DOX), and a higher loading capacity (90.1 ± 0.5 %) was achieved. The in-vitro drug release study showed low release rates in simulated physiological environments (pH 7.4, 37 °C, lower than about 20 %), but higher release rates in tumor tissue conditions (pH 4.5, 41 °C, higher than about 60 %) over 96 h, allowing for sustained and extended delivery of DOX. Additionally, the MTT assay demonstrated that the blank and DOX-loaded CS/Fe3O4/Cu-MOF had good cytocompatibility (over 80 % cell viability) and considerable cytotoxicity (lower than 40 % at 16 μg/mL) toward breast cancer (MCF-7) cell line, respectively. These results indicated that the synthesized nanocomposite with suitable pH-sensitivity has potential as a targeted anticancer agent.

Design of oscillatory helical baffled reactor and dual functional mesoporous catalyst for oxidative desulfurization of real diesel fuel

Enhancing real diesel fuel properties by expelling pollutants using a new design has received considerable interest in the present day. This work investigates the conversion of sulfur compounds via oxidation reaction with peracetic acid as an oxidant. For this purpose, a dual functional mesoporous catalyst was synthesized via loading active metal (iron oxide) nanoparticles over mesopore γ-alumina-anatase titanium oxide prepared via the impregnation procedure (IWI) and precipitation methods, respectively. The novel design of the mesoporous catalyst represents the dual functional catalyst in the oxidative desulfurization process (ODS). The mesoporous catalyst that was formulated underwent a comprehensive analysis using various characterization techniques such as physical adsorption-desorption under N2, X-ray diffraction-XRD, Fourier transforms infrared spectroscopy-FTIR, Field Emission Scanning Electron Microscopy-FESEM, Energy dispersive X-ray analyzer-EDX, and thermogravimetric analysis-TGA. A newly designed laboratory pilot plant for an oscillatory helical baffled reactor (OHBR) was developed and utilized for the ODS process to evaluate the performance of the synthesized mesopore catalyst. The investigated rapid conversion for sulfur removal was found to be 98.42 % under ambient operating conditions such as oscillation of frequency 2 Hz, oscillation of amplitude 8 mm, temperature of oxidation 80°C, and residence time of 9 min. It is clearly observed that the new design of OHBR and mesoporous catalyst highly affected sulfur removal, resulting in a clean diesel.

An Enzyme-Induced Carbonate Precipitation Method for Zn2+, Ni2+, and Cr(VI) Remediation: An Experimental and Simulation Study

Heavy metal contamination has long been a tough challenge. Recently, enzyme-induced carbonate precipitation (EICP) has been proposed to handle this problem. This paper aims to explore the efficacy, process, and mechanisms of EICP using crude sword bean urease extracts to remediate Zn2+, Ni2+, and Cr(VI) contamination. A series of liquid batch tests and geochemical simulations, as well as microscopic analyses, were conducted. The liquid batch test results show that Zn2+, Ni2+, and Cr(VI) can be effectively immobilized by the EICP method, and the highest immobilization percentage was observed for Zn2+, reaching up to 99%. Ni2+ and Cr(VI) were immobilized at 62.4% and 24.4%, respectively. Additionally, the immobilization percentage of heavy metals increased with the concentration of added Ca2+. The simulation results and XRD results reveal that the organic molecules in crude sword bean urease can promote ZnCO3, Zn(OH)2, Zn5(CO3)2(OH)6, and NiCO3 precipitation. The FTIR and SEM-EDS results provide evidence for heavy metal adsorption by the functional groups in crude urease and calcium carbonate. The liquid batch test results, as well as the simulation results and the microscopic analysis results, indicate that the mechanism of EICP in heavy metal remediation can be summarized as biomineralization to form heavy metal carbonate precipitates and metal hydroxide precipitates, adsorption by calcium carbonate, and adsorption or complexation or promoting nucleation by organic molecules.

Summary of the Research Progress on Advanced Engineering, Processes, and Process Parameters of Rare Earth Green Metallurgy.

The addition of rare earth metals to aluminum alloys can effectively improve their corrosion resistance and has been widely used in the aerospace and military industries. However, the current methods for the preparation of rare earth metals involve long processing steps, high energy consumption, and high carbon emissions, which severely constrains the development of aluminum alloys. Its output is further developed. To this end, this paper reviews mainstream rare earth production processes (precipitation methods, microemulsion methods, roasting-sulfuric acid leaching methods, electrochemical methods, solvent extraction methods, and ion exchange methods) to provide basic information for the green smelting of rare earth metals and help promote the development of green rare earth smelting. Based on the advantages and disadvantages of each process as well as recent research results, the optimal process parameters and production efficiency were summarized. Studies have concluded that the precipitation method is mostly used for the recovery of rare earth elements and related valuable metals from solid waste; the microemulsion method is mostly used for the preparation of nanosized rare earth alloys by doping; the roasting-sulfuric acid leaching method is mostly used for the treatment of raw rare earth ores; and the molten salt electrolysis method is a more specific method. This is a green and environmentally friendly production process. The results of this study can provide direction for the realization of green rare earth smelting and provide a reference for improving the existing rare earth smelting process.

Effect of carboxylate additives on CaCO3 particle size by precipitation method using scallop shell

Effect of carboxylate additives on CaCO3 particle size by precipitation method using scallop shell

Surfactant-Free Synthesis of Melon Seed-Like CeO2 and Ho@CeO2 Nanostructures with Enriched Oxygen Vacancies: Characterization and Their Enhanced Antibacterial Properties.

To overcome the poor antibacterial performance of cerium oxide (CeO2) nanoparticles at low concentrations, melon seed-shaped CeO2 (MS-CeO2) and holmium (Ho)-doped CeO2 (Ho@MS-CeO2) nanoparticles were synthesized using a simple precipitation method without the addition of any surfactants. The surface morphology, phase structure, crystallinity, Ce3+ and Ce4+ valence, lattice defects, and reactive oxygen species (ROS) production of both synthesized nanostructures were examined using different techniques, i.e., scanning electron microscopy (SEM), energydispersive X-ray (EDX), resolution transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), Raman spectroscopy, ultraviolet (UV) spectra, fluorescence spectra, and zeta potential (ζ). The results show that under certain stirring and aging temperatures, CeO2 and Ho-doped CeO2 nanoparticles with a melon seed-like morphology can be prepared in a short period. Both nanoparticles were tested as antiseptic agents against G+ and G - bacteria (E. coli and S. aureus), and the results confirmed that the Ho@MS-CeO2 nanostructures exhibited remarkable antimicrobial activity at a low concentration (0.5 mg/L) compared with the control group, which is attributed to the reversible conversion of Ce3+ and Ce4+ in the ceria crystal lattice, enriched oxygen vacancy, ROS species production, and positive surface charge.

Tailored solar collector coatings: Synthesis and characterization of CuFe2O4/PANI nanocomposites

This work successfully synthesized CuFe2O4 nanoparticles and CuFe2O4/PANI nanocomposites via a simple chemical precipitation method followed by in-situ polymerization. The main objective is to investigate the solar selective properties of these novel nanomaterials for solar collector applications. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy were used to characterize phase structure and crystallite sizes. Scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), and UV–vis spectroscopy were performed to examine the morphology and optical characteristics of the nanostructures. XRD confirmed the development of spinel copper ferrite nanoparticles and copper ferrite/PANI nanocomposites with average crystallite sizes of 20.64 ± 4.04 nm, consistent with FT-IR and Raman results. Optical direct band gaps, estimated using Tauc plots, ranged from 2.7 eV to 3.3 eV for copper ferrite nanoparticles and reduced to 2.5 eV–3.0 eV with polyaniline inclusion. Reflectance spectra showed that CuFe₂O₄/PANI nanocomposites exhibited strong solar absorptance (αs) of 95 % in the visible spectrum and reduced emittance (εt) of 1 % in the infrared region, with a superior selectivity of 96.28 %. These nanocomposites can emerge as a novel class of selective coating materials with outstanding selective optical properties.

Microstructural and Optical Effects of Zn-Doped Magnesium Oxide Nanoparticles Obtained by the Precipitation Method

Microstructural and Optical Effects of Zn-Doped Magnesium Oxide Nanoparticles Obtained by the Precipitation Method

Synthesis of hydroxyapatite and strontium-substituted hydroxyapatite for bone replacement and osteoporosis treatment

Hydroxyapatite (HAp) is an inorganic component exhibiting bioactivity similar to that of natural bone. However, it is not resorbed by osteoclasts during bone remodelling due to its lack of bio-resorption property. This can be enhanced by the substitution of other element presented in bone mineral. In this research work, hydroxyapatite (HAp) and strontium-substituted hydroxyapatite (Sr-HAp) were synthesized by a precipitation method. Calcium nitrate tetra hydrate [Ca(NO3)2•4H2O], disodium hydrogen phosphate (Na2HPO4), and Strontium nitrate [Sr(NO3)2] were used as Ca, PO4 and Sr sources, respectively. Molar ratio Ca/P=1.67 was used to synthesize HAp, where (Ca+Sr)/P=1.67 was used to synthesize strontium substituted-HAp (Sr-HAp). The reaction was carried out at room temperature. The results show that pure HAp and Sr-HAp were formed with nanometer-sized particles. Sr substitution in the HAp lattice results in an increase in both the lattice disorder and crystal aspect ratio. The results of in vitro bioactive testing using simulated bodily fluid also showed that both HAp and Sr-HAp have high bioactive, with the Sr-HAp sample having the greater bioactive. Therefore, HAp and Sr-HAp have great potential for biological applications.

Impacts of future climate change on rice yield based on crop model simulation—A meta-analysis

Rice is one of the world's major food crops. Changes in major climatic factors such as temperature, rainfall, solar radiation and carbon dioxide (CO2) concentration have an important impact on rice growth and yield. However, many of the current studies that predict the impact of future climate change on rice yield are affected by uncertainties such as climate models, climate scenarios, model parameters and structure, and showing great differences. This study was based on the assessment results of the impact of climate change on rice in the future of 111 published literature, and comprehensively analyzed the impact and uncertainty of climate change on rice yield. This study utilized local polynomial (Loess) regression analysis to investigate the impact of changes in mean temperature, minimum temperature, maximum temperature, solar radiation, and precipitation on relative rice yield variations within a complete dataset. A linear mixed-effects model was used to quantitatively analyze the relationships between the restricted datasets. The qualitative analysis based on the entire dataset revealed that rice yields decreased with increasing average temperature. The precipitation changed between 0 and 25 %, it was conducive to the stable production of rice, and when the precipitation changed >25 %, it would cause rice yield reduction. The change of solar radiation was less than −1.15 %, the rice yield increases with the increase of solar radiation, and when the change of solar radiation exceeds −1.15 %, the rice yield decreases. Elevated CO2 concentrations and management practices could mitigate the negative effects of climate change. The results of a quantitative analysis utilizing the mixed effects model revealed that average temperature, precipitation, CO2 concentration, and adaptation methods all had a substantial impact on rice production, and elevated CO2 concentrations and management practices could exert positive influences on rice production. For every 1 °C and 1 % increase in average temperature and precipitation, rice yield decreased by 3.85 % and 0.56 %, respectively. For every 100 ppm increase in CO2 concentration, rice yield increased by 7.1 %. The variation of rice yield under different climate models, study sites and climate scenarios had significant variability. Elevated CO2 concentrations and management practices could compensate for the negative effects of climate change, benefiting rice production. This study comprehensively collected and analyzed a wide range of literature and research, which provides an in-depth understanding of the impacts of climate change on rice production and informs future research and policy development.

Microcube formation and characterization of cobalt and nickel selenite dihydrate: Thermal, spectral, and dielectric insights

This paper outlines the template-free preparation of cobalt and nickel selenite dihydrate microcubes using a simple precipitation method from aqueous solutions at room temperature. Structural analysis revealed the formation of pure, well-crystallized isostructural cobalt and nickel selenite dihydrate, exhibiting monoclinic crystal systems of space group P21/n. Thermal analysis showed distinct decomposition patterns for both compounds, highlighting their thermal stabilities. The intermediate formed after water loss were stable up to ∼550 °C, and crystallized before decomposing into their respective oxides via SeO2 sublimation. Scanning electron microscopy (SEM) images illustrated the presence of irregular-sized well-defined microcubes with smooth surfaces and sharp edges, distributed across the material. The formation of these microstructures is likely driven by self-aggregation and the Ostwald ripening process. Dielectric studies on pelletized materials revealed higher dielectric constants at low frequencies with minimal dielectric loss. CoSeO3⋅2H2O exhibited higher dielectric constants than NiSeO3⋅2H2O due to the larger ionic radius of Co2+ ions, which leads to a greater degree of polarization compared to Ni2+ ions. The considerably higher dielectric constant with an insignificant amount of dielectric loss indicates the materials’ potential for applications in dielectric and microwave technologies.

Lattice contraction and Surface stress investigation in nanoparticles of zinc sulfide

Nanostructured zinc sulfide was synthesized through controlled chemical precipitation method using zinc chloride and sodium sulfide as starting materials. Zinc sulfide nanoparticle with different average grain sizes were obtained by annealing the as prepared sample at different temperatures in inert atmosphere. The samples were characterized using XRD, TEM, and SAED. The lattice contraction, which have significant impact on the electrical and mechanical properties of nanomaterials were studied using Hall-Williamsons analysis. The lattice contraction present in nanoparticles of zinc sulfide with different average particle size at different planes was studied. The observed lattice contraction in nanoparticles of zinc sulfide seems to have contributions from micro strain over and above the contribution from quantum confinement effect due to small particle size and it follows an inverse proportional relationship with the particle size.The present paper discusses the reduced unit cell size in ZnS nanoparticles, along with their diminutive particle size, and its contribution to the broadening of X-ray diffraction peaks.

Efficient Photocatalytic Degradation of Triclosan and Methylene Blue by Synthesized Ag-Loaded ZnO under UV Light

Industrial discharge of hazardous organic and synthetic chemicals, such as antibacterials and dyes, poses severe risks to human health and the environment. This study was conducted to address the urgent need for efficient and stable zinc-oxide-based photocatalysts to degrade such pollutants. A novel approach to synthesizing silver-loaded zinc oxide (Ag@Z) catalysts was introduced by using a simple and efficient combination of hydrothermal and precipitation methods. Comprehensive characterization of Ag@Z photocatalysts was performed using XRD, XPS, Raman, UV–vis adsorption, FTIR, and SEM, revealing an enhancement of structural, optical, and morphological properties in comparison to pure zinc oxide. Notably, the 5%Ag@Z catalyst exhibited the highest degradation efficiency among the other synthesized catalysts under UV-C light irradiation, and enhanced the degradation rate of pure zinc oxide (Z) by 1.14 and 1.64 times, for Triclosan (TCS) and Methylene Blue (MB), respectively. the effect of catalyst dose and initial concentration was studied. A mechanism of degradation was proposed after investigating the effect of major reactive species. The 5%Ag@Z catalyst increased the photostability, which is a major problem of zinc oxide due to photocorrosion after reusability. We found that 50% and 74% of energy consumption for the photocatalytic degradation of TCS and MB by 5%Ag@Z, respectively, was saved in compassion with zinc oxide. The remarkable photocatalytic performance and the good recovery rate of Ag@Z photocatalysts demonstrate their high potential for photocatalytic degradation of organic contaminants in water.

Photocatalytic and electrochemical investigation of Mn and Sn co-doped ZnO nanoparticles: Effect of doping concentration

The chemical precipitation method is employed to prepare the Mn and Sn co-doped ZnO nanoparticles with various doping concentrations. Debye Scherrer’s formula, Williamson-Hall equation and Halder-Wagner methods are used to calculate the crystallite size of the prepared nanoparticles. The addition of dopants enhances the periodicity of the atoms. The bond lengths, second nearest neighbor distances and bond angles are examined. The purity of the samples is confirmed using energy dispersive X-ray analysis technique. The process of doping reduces the maximum optical absorption. The dopants reduce the band gap of the prepared nanoparticles and the band gap ranges from 3.07 eV to 3.03 eV. The charge carrier concentrations are calculated from the optical band gap. The Hall coefficient of the prepared nanoparticles increases due to the addition of the dopants. The refractive index of the material is also examined. The quenching is observed in the photoluminescence spectrum due to the dopants. The dielectric properties and electric modulus depend on doping concentrations of Mn and Sn. The degradation of the Congo red and methylene blue dyes with prepared nanoparticles as catalysis is reported. The specific charge of the Mn and Sn co-doped ZnO-based electrode is analyzed using cyclic voltammetric study and galvanostatic charge–discharge technique.

Sintesis dan Karakterisasi Pupuk Multinutrien Calcium-Ammonium-Phosphate (CAP) Berbahan Cangkang Kupang Merah

Fertilisers and composites are two types of materials that can be used to improve soil fertility. However, these two materials have some differences. One of them is in the manufacturing process, fertilisers can be made in various ways, while the composite manufacturing process can only be done by biological processes. The objectives of this paper are (1) To determine the effect of acidity degree (pH) on the formation of Calcium-Ammonium-Phosphate particles, (2) To determine the optimisation of Calcium Ammonium Phosphate from red mussel shells by precipitation method, and (3) To determine the characteristics of Calcium-Ammonium-Phosphate produced using SEM-EDX and XRF analysis. The type of research used uses experimental research. The results and conclusions drawn are (1) The solubility of CaHPO4 decreases with increasing pH so that the weight of the resulting product increases in the precipitation method, (2) The best condition for making calcium ammonium phosphate fertiliser with red shell material is in the condition of red shell weight of 30 grams and pH 7, (3) The chemical composition contained in the CAP product with the condition of 20 grams of shell weight at pH 5 is Ca content of 74.76%, and phosphorus content of 23.5%, (4) The particle size at pH 3 weight of 20 grams ranges from 830 nm - 1970 nm and the particle size at pH 3 weight of 30 grams ranges from 1980 nm - 5220 nm. Therefore the fertiliser product does not include nano particles, (5) The CAP fertiliser product meets the SNI standards for NPK fertiliser and dolomite fertiliser.

A simple and sensitive high-performance liquid chromatographic method combined with fluorescence detection for bioanalysis of scopoletin in rat plasma: Application to a pharmacokinetic study.

Scopoletin, a coumarin class natural phytoalexin, is present in medicinal plants such as noni (Morinda citrifolia). It exhibits diverse pharmacological properties, including antioxidant, anti-hyperuricemic, and anti-inflammatory effects. The objective of this study was to develop a novel HPLC-fluorescence (HPLC-FL) method for the quantitative analysis of scopoletin in the plasma and to investigate its pharmacokinetics in rats. Sample preparation involved a methanol-based protein precipitation method, and chromatographic separation was conducted using a C18 column with an isocratic mobile phase composed of water and acetonitrile containing 0.1% trifluoroacetic acid. The eluent was detected using an FL detector set to optimized excitation/emission wavelengths of 337/453 nm. Method validation encompassed assessments of selectivity, linearity (1-500 ng/mL), precision, accuracy, recovery, matrix effect, and stability in accordance with the prevailing Food and Drug Administration (FDA) guidelines. The developed method was successfully applied for pharmacokineticstudy in rats. To the best of our knowledge, this study is the first application of a simple and sensitive HPLC-FL method for the quantification of scopoletin in a pharmacokinetic study. This method offers a promising alternative for preclinical pharmacokinetic investigations with appropriate modifications and validations and holds potential for clinical applications.

Ag-bridged Z-scheme AgI/NU-1000 heterojunction for enhanced photocatalytic degradation of sulfamethazine: Pathways, mechanism insight, and DFT calculations

Constructing heterojunction structures is a crucial approach for improving carrier separation efficiency and expanding the visible-light absorption range of photocatalysts. Herein, a series of Ag-bridged Z-scheme (AgI/NU-1000) heterojunction photocatalysts were successfully prepared using a simple in-situ precipitation method. The photodegradation efficiency of the AgI/NU-1000 samples was assessed by degrading sulfamethazine under visible-light conditions. The optimized AgI/NU-10000.35 (AN-2) photocatalyst exhibited exceptional photodegradation activity, achieving a degradation rate of 89.68 % within 40 min. The toxicity test results proved that the solution degraded by AN-2 exhibited no detrimental effects on biological growth, thereby demonstrating its potential practical application value. Electrochemical and photochemical tests demonstrated that the creation of a Z-scheme heterojunction was favorable for the separation of photogenerated carriers. Density functional theory (DFT) calculations and X-ray photoelectron spectroscopy were used to clarify the electron migration direction within the AgI/NU-1000 heterojunction. Possible degradation pathways and mediate products were investigated using high-performance liquid chromatography–mass spectrometry and DFT calculations. This work demonstrates the potential application of AgI/NU-1000 composite materials in environmental treatment.

Z-scheme based photoactive ZnO:TiO2:CdO:g-C3N4 nanocomposites for advance oxidation process

Z-scheme-based hybrid [(ZnO0.40:0.60TiO2):CdO1.00]:g-C3N4] nanocomposites (NCs) were synthesized by sol-gel precipitation and thermal polycondensation methods. Microscopic FE-SEM images varied from a compact crystal-like structure to a mesoporous sheet-type structure. XRD patterns confirmed the polycrystallinity for all samples. Meanwhile, the g-C3N4 interacts extensively with Zn+2 and Cd+2. The optical bandgap increased from 2.12 eV to 2.25 eV with the addition of g-C3N4 concentration. Z-scheme [(ZnO0.40:0.60TiO2):CdO1.00]:[g-C3N4] NCs of the particular composition named ZTCG4 showed the highest photocatalytic activity and degraded the methylene blue (MB), methyl green (MG), and methyl orange (MO) to be 99.7 %, 99.8 %, and 99.9 %, respectively, under the illumination of the visible light. Mineralized factors: chemical oxygen demand (COD) and biochemical oxygen demand (BOD) achieved the maximum removal efficiencies of 89.4 % and 88.9 % for the sample g-C3N4. Prepared photocatalysts can be utilized to remove the organic pollutants from the drainage systems under visible light exposure.

Protective Encapsulation of a Bioactive Compound in Starch-Polyethylene Glycol-Modified Microparticles: Degradation Analysis with Enzymes.

Starch is a promising polymer for creating novel microparticulate systems with superior biocompatibility and controlled drug delivery capabilities. In this study, we synthesized polyethylene glycol (PEG)-modified starch microparticles and encapsulated folic acid using a solvent-mediated acid-base precipitation method with magnetic stirring, which is a simple and effective method. To evaluate particle degradation, we simulated physiological conditions by employing an enzymatic degradation approach. Our results with FTIR and SEM confirmed the successful synthesis of starch-PEG microparticles encapsulating folic acid. The average size of starch microparticles encapsulating folic acid was 4.97 μm and increased to 6.01 μm upon modification with PEG. The microparticles were first exposed to amylase at pH 6.7 and pepsin at pH 1.5 at different incubation times at physiological temperature with shaking. Post-degradation analysis revealed changes in particle size and morphology, indicating effective enzymatic degradation. FTIR spectroscopy was used to assess the chemical composition before and after degradation. The initial FTIR spectra displayed characteristic peaks of starch, PEG, and folic acid, which showed decreased intensities after enzymatic degradation, suggesting alterations in chemical composition. These findings demonstrate the ongoing development of starch-PEG microparticles for controlled drug delivery and other biomedical applications and provide the basis for further exploration of PEG-starch as a versatile biomaterial for encapsulating bioactive compounds.

TSQ Incubation Enhances Autometallographic Zinc Detection in Cultured Astrocytes.

Zinc is a critical ion for a large number of cellular functions. In the central nervous system, zinc ions are involved in synaptic transmission. Therefore, zinc homeostasis is essential, and cells have developed a variety of mechanisms to control cellular zinc concentration, including the zincosome formation. Alterations of free zinc levels have been associated with brain dysfunction and are present in many illnesses and syndromes. Astrocytes are implicated in the maintenance of the neuronal milleu and brain homeostasis. In this work, we have analyzed the combination of direct (TSQ) and indirect (autometallography) zinc detection methods to increase sensitivity for studying zinc uptake by rat astrocytes in vitro. Zincosome formation was visualized with the zinc fluorochrome TSQ by light microscopy. Additionally, we improved both zinc precipitation and cellular fixation methods to preserve zinc ions and make them suitable for autometallography development. Our tests pinpointed paraformaldehyde and sodium sulfide as the more adequate methods for cellular fixation and zinc precipitation, respectively. TSQ incubation and pH of the fixative were shown to be crucial for autometallography. Using this improved method, we visualized the zinc content of zincosomes at the ultrastructural level both as silver autometallographic precipitates and as electrodense sulfide-osmium zinc precipitates.