Effect of Potassium Permanganate on Staphylococcal Isolates Derived from the Skin of Patients with Atopic Dermatitis.

In atopic dermatitis (AD), Staphylococcus aureus frequently colonizes lesions, leading to superinfections that can then lead to exacerbations. The presence of biofilm-producing isolates has been associated with worsening of the disease. Potassium permanganate is used as a topical treatment of infected eczema, blistering conditions, and wounds. Little is known of its effects against microbes in AD skin. The aim of this study was to explore antibacterial and antibiofilm properties of potassium permanganate against staphylococcal isolates derived from AD skin. Viable count and radial diffusion assays were used to investigate antibacterial effects of potassium permanganate against planktonic staphylococcal isolates. The antibiofilm effects were assessed using biofilm assays and scanning electron microscopy. The Staphylococcus aureus isolates were completely killed when exposed to 0.05% of potassium permanganate. In concentrations of 0.01%, potassium permanganate inhibited bacterial biofilm formation. Eradication of established staphylococcal biofilm was observed in concentrations of 1%. Electron microscopy revealed dense formations of coccoidal structures in growth control and looser formations of deformed bacteria when exposed to potassium permanganate. This suggests antibacterial and antibiofilm effects of potassium permanganate against staphylococcal isolates derived from AD skin, when tested in vitro, and a potential role in the treatment of superinfected AD skin.

Simple dual-readout immunosensor based on phosphate-triggered and potassium permanganate for visual detection of fenitrothion.

Multicolor-based visual immunosensor is a promising tool for rapid analysis without the use of bulky instruments. Herein, an anti-fenitrothion nanobody-alkaline phosphatase fusion protein (VHHjd8-ALP) was employed to develop a multicolor visual immunosensor (MVIS) and a ratiometric fluorescence MVIS (RFMVIS, respectively). After one-step competitive immunoassay, the VHHjd8-ALP bound to microplate catalyzed phenyl phosphate disodium salt (ArP) into phenol. Under high alkaline condition (pH 12), the phenol reduced KMnO4 to intermediate (K2MnO4) and further to MnO2 in alkaline condition (pH 12), accompanied by a visible color transition of purple-green-yellow, which can be used for semiquantitative visual analysis or qualitative detection by measuring RGB value. RFMVIS was proposed on the basis of MVIS to further improve sensitivity. The CdTe quantum dot and fluorescein were used as signal probes to develop the fluorescent immunosensor. The CdTe dots with red emission (644 nm) was quenched by oxidation of KMnO4, whereas the fluorescein with green emission (520 nm) remained constant, accompanied by a fluorescent color transition of green-yellow-red. By measuring the ratio of the fluorescence intensity (I644/I520), the ratiometric fluorescence immunosensor was developed for qualitative analysis. The two visual immunosensors were sensitive and simple, and they showed good accuracy and practicability in the recovery test, thus are ideal tools for rapid screening.

Experimental evidence of effective disinfectant to control the transmission of Micropterus salmoides rhabdovirus.

Micropterus salmoides rhabdovirus (MSRV) is a significant pathogen that causes high morbidity and mortality in largemouth bass, leading to enormous economic losses for largemouth bass aquaculture in China. The aim of this study was to investigate the efficacy of four disinfectants (potassium permanganate, glutaraldehyde, trichloroisocyanuric acid and povidone iodine) on MSRV, to control the infection and transmission of MSRV in largemouth bass aquaculture. The disinfectants were tested at different concentrations (5, 25, 50, 100 and 500 mg/L) prepared with distilled water for 30 min contact time, and the viral nucleic acid was quantified using qPCR and the infectivity was tested by challenge experiment. Potassium permanganate at 5-500 mg/L, glutaraldehyde at 500 mg/L, trichloroisocyanuric acid at 50-500 mg/L and povidone iodine at 500 mg/L concentration could effectively decrease the virus nucleic acid, and the survival rate of largemouth bass juveniles after challenge experiment increased significantly from 3.7% ± 6.41% to 33.33 ± 11.11% - 100%. Moreover, the minimum effective time of 5 mg/L potassium permanganate was further studied at 2, 5, 10 and 20 min contact time. The viral nucleic acid decreased significantly at 5-20 min exposure time, and the survival rate increased significantly from 7.41% ± 6.41% to 77.78 ± 11.11% - 100%. The median lethal concentration (LC50 ) values of potassium permanganate were 10.64, 6.92 and 3.7 mg/L at 24, 48 and 96 h, respectively. Potassium permanganate could be used for the control of MSRV in the cultivation process; the recommended concentration is 5 mg/L and application time should be less than 24 h. The results could be applied to provide a method to control the infection and transmission of MSRV in water, and improve the health status of largemouth bass.

Depigmentation of Melanin-containing Tissues Using Hypochlorous Acid to Enhance Hematoxylin-eosin and Immunohistochemical Staining.

Pathologists diagnose diseases by observing the histologic and cellular morphology microscopically. However, the high pigmentation in melanin-containing tumors can hide the tumor cell structures, making diagnosing challenging. Previously, hydrogen peroxide and potassium permanganate were utilized for melanin bleaching with several limitations. For instance, hydrogen peroxide has a weak bleaching ability, and the process is time-consuming (12 h). Meanwhile, potassium permanganate affects the antigenicity of antigens and is unsuitable for immunohistochemical (IHC) staining. In this study, the hypochlorous acid (HClO) solution was applied to hematoxylin-eosin and IHC staining of melanin tissue sections. The study discovered that 1% HClO could completely bleach melanin particles in tumor tissues in a short period (19.95 ± 2.53 min) without compromising the hematoxylin-eosin staining. In addition, 2% HClO was utilized for bleaching at room temperature for 61.17 ± 4.32 minutes after the tissue was incubated with 3,3'-diaminobenzidine in IHC staining. This treatment effectively removed melanin without negatively impacting 3,3'-diaminobenzidine signal expression, thus ensuring that the sections met the necessary diagnostic requirements. Therefore, this method could facilitate pathologists in disease diagnosis of melanin-containing tissues.

Al and Mn speciation changes during the pre-oxidation with potassium permanganate and coagulation removing natural organic matter and its membrane fouling behavior.

In this study, we systematically explore coagulation behavior, ultrafiltration membrane fouling behavior and the mechanism involved in during the process of pre-oxidation of potassium permanganate and coagulation of aluminum chloride at different condition to treat model pollutants (humic acid, HA) and natural water. The KMnO4 pre-oxidation significantly enhances flocs formation, and for HA artificial water the flocs size increases from 82 to 122 µm at pH 5.5, from 63 to 185 µm at pH 7.0 and from 0 to 75 µm at pH 8.5, respectively, as for natural water it increases from 72 to 139 µm. The enhanced coagulation at pH 5.5 is attributed to the increased polymeric Al speciation after pre-oxidation along with the generated Mn2+ damaging the electric double layer structure. And for pH 8.5 it is mainly caused by the in-situ MnO2 as combination nuclei during pre-oxidation. Besides, for pH 7.0, the combined effect of in-situ MnO2 and the increased polymeric Al speciation both contribute to improvement of the coagulation. What's more, the enhanced Al coagulation by pre-oxidation of KMnO4 also helps alleviate the membrane fouling for both HA artificial water and natural water, and a much rougher surface with larger flocs forms after KMnO4-aided Al coagulation filtration. This study provides an alternative perspective on the mechanism of pre-oxidation coagulation process.

Synthesis of lignin nanoparticle­manganese dioxide complex and its adsorption of methyl orange.

Lignin nanoparticles (LNPs) were synthesized using an anti-solvent method and subsequently loaded with manganese dioxide (MnO2) via potassium permanganate treatment, resulting in the formation of MnO2@LNPs. An extensive investigation was conducted to elucidate the influence of MnO2@LNPs on the decolorization of methyl orange solution. The LNPs were successfully obtained by adjusting the preparation parameters, yielding particles exhibited average sizes ranging from 300 to 600 nm, and the synthesis process exhibited a high yield of up to 87.3% and excellent dispersion characteristics. Notably, LNPs size was reduced by decreasing initial concentration, increasing stirring rate, and adding water. In the acetone-water two-phase system, LNPs self-assembled into spherical particles driven by π-π interactions and hydrogen bond forces. Oxidation modification using potassium permanganate led to the formation of nanoscale MnO2, which effectively combined with LNPs. Remarkably, the resulting MnO2@LNPs demonstrated a two-fold increase in methyl orange adsorption capacity (227 mg/g) compared to unmodified LNPs. The process followed the Langmuir isotherm model and was exothermic.

Potassium permanganate modification of hydrochar enhances sorption of Pb(II), Cu(II), and Cd(II).

Hydrochars formed by hydrothermal carbonization of hickory wood, bamboo, and wheat straw at 200 °C were modified by potassium permanganate (KMnO4) for the sorption of Pb(II), Cd(II), and Cu(II). The wheat straw hydrochar (WSHyC) modified with 0.2 M KMnO4 resulted in the most promising adsorbent (WSHyC-0.2KMnO4). Characterization of WSHyC and WSHyC-0.2KMnO4 revealed that the modified hydrochar features large specific surface area, rich of surface oxygenic functional groups (OCFG), and a significant amount of MnOx micro-particles. Batch adsorption experiments indicated that the adsorption rate by WSHyC-0.2KMnO4 was faster than for WSHyC, attaining equilibrium after around 5 h. The optimum adsorption capacity (Langmuir) of Pb(II), Cd(II), and Cu(II) by WSHyC-0.2KMnO4 was 189.24, 29.06 and 32.68 mg/g, respectively, 12 âˆ¼ 17 times greater than by WSHyC. The significantly enhanced heavy metal adsorption can be attributable to the increased OCFG and MnOx microparticles on the surface, thereby promoting ion exchange, electrostatic interactions, and complexation mechanisms.

Enhancement of KMnO4 treatment on cyanobacteria laden-water via 1000 kHz ultrasound at a moderate intensity.

1000 kHz high-frequency ultrasound at 0.12 and 0.39 W/mL intensity was used to enhance the inactivation of suspensions of Microcystis aeruginosa cells using KMnO4. With 10 mg/L of KMnO4, ultrasound at 0.12 W/mL intensity was found to be effective in inactivating the cyanobacteria within 10 min. A Weibull model was found to describes the inactivation well. Its concave shape shows that some cells have a certain resistance to this treatment. Cytometry and microscopic analysis confirm that the treatment damages cell integrity. Despite that the extracellular organic matter in the water was not significantly increased. The concentration of extracellular cyanobacterial toxins even decreased. The filtered suspension of inactivated cyanobacteria was used to cultivate mung beans, and the suspension did not hinder their germination. This provides a new idea for using cyanobacteria-laden wastewater. These findings suggest a technique for speeding up the oxidation of Microcystis cells using KMnO4 with ultrasound at moderate intensity, which provide new insights into the biological effects of ultrasound.

Multiple roles of UV/KMnO4 in cyanobacteria containing water treatment: Cell inactivation & removal, and microcystin degradation.

Cyanobacterial blooms present great challenges to drinking water treatment and human health. The novel combination of potassium permanganate (KMnO4) and ultraviolet (UV) radiation is engaged as a promising advanced oxidation process in water purification. This study investigated the treatment of a typical cyanobacteria, Microcystis aeruginosa by UV/KMnO4. Cell inactivation was significantly improved by UV/KMnO4 treatment, compared to UV alone or KMnO4 alone, and cells were completely inactivated within 35 min by UV/KMnO4 in natural water. Moreover, effective degradation of associated microcystins was simultaneously achieved at UV fluence rate of 0.88 mW cm-2 and KMnO4 dosages of 3-5 mg L-1. The significant synergistic effect is possibly attributable to the highly oxidative species produced during UV photolysis of KMnO4. In addition, the cell removal efficiency via self-settling reached 87.9 % after UV/KMnO4 treatment, without additional coagulants. The fast in situ generated manganese dioxide was responsible for the enhancement of M. aeruginosa cell removal. This study firstly reports multiple roles of UV/KMnO4 process in cyanobacterial cell inactivation and removal, as well as simultaneous microcystin degradation under practical conditions.

[Removal Performance and Mechanism of Potassium Permanganate Modified Coconut Shell Biochar for Cd(â ¡) and Ni(â ¡) in Aquatic Environment].

In this study, coconut shell biochar modified by KMnO4 (MCBC) was used as the adsorbent, and its removal performance and mechanism for Cd(Ⅱ) and Ni(Ⅱ) were discussed. When the initial pH and MCBC dosage were separately 5 and 3.0 g·L-1, respectively, the removal efficiencies of Cd(Ⅱ) and Ni(Ⅱ) were both higher than 99%. The removal of Cd(Ⅱ) and Ni(Ⅱ) was more in line with the pseudo-second-order kinetic model, indicating that their removal was dominated by chemisorption. The rate-controlling step for Cd(Ⅱ) and Ni(Ⅱ) removal was the fast removal stage, for which the rate depended on the liquid film diffusion and intraparticle diffusion (surface diffusion). Cd(Ⅱ) and Ni(Ⅱ) were mainly attached to the MCBC via surface adsorption and pore filling, in which the contribution of surface adsorption was greater. The maximum adsorption amounts of Cd(Ⅱ) and Ni(Ⅱ) by MCBC were individually 57.18 mg·g-1 and 23.29 mg·g-1, which were approximately 5.74 and 6.97 times that of the precursor (coconut shell biochar), respectively. The removal of Cd(Ⅱ) and Zn(Ⅱ) was spontaneous and endothermic and had obvious thermodynamic characteristics of chemisorption. Cd(Ⅱ) was attached to MCBC through ion exchange, co-precipitation, complexation reaction, and cation-π interaction, whereas Ni(Ⅱ) was removed by MCBC via ion exchange, co-precipitation, complexation reaction, and redox. Among them, co-precipitation and complexation were the main modes of surface adsorption of Cd(Ⅱ) and Ni(Ⅱ). Additionally, the proportion of amorphous Mn-O-Cd or Mn-O-Ni in the complex may have been higher. These research results will provide important technical support and theoretical basis for the practical application of commercial biochar in the treatment of heavy metal wastewater.

Flow injection chemiluminescence determination of acetochlor and cartap-HCl in freshwater samples using an acidic KMnO4 -rhodamine-B reaction system.

A flow injection (FI) methodology using the acidic potassium permanganate (KMnO4 )-rhodamine-B (Rh-B) reaction with chemiluminescence (CL) detection was established to determine acetochlor and cartap-HCl pesticides in freshwater samples. Experimental parameters were optimized, and Chelex-100 cationic exchanger mini column and solid-phase extraction (SPE) were used as phase separation techniques. Linear calibration curves were observed for the standard solutions of acetochlor and cartap-HCl over the ranges 0.005-2.0 mg L-1 [y = 1155.8x + 57.551, R2  = 0.9999 (n = 8)] and 0.005-1.0 mg L-1 [y = 979.76x + 14.491, R2  = 0.9998 (n = 8)] with LODs and LOQs of 7.5 × 10-4 and 8.0 × 10-4  mg L-1 (3σ blank) and 2.5 × 10-3 and 2.7 × 10-3  mg L-1 (10σ blank), respectively, with an injection throughput of 140 h-1 . These methods were used to estimate acetochlor and cartap-HCl with or without the SPE procedure, respectively, in spiked freshwater samples. Results obtained were not significantly different at a 95% confidence level to those of other reported methods. Recoveries for acetochlor and cartap-HCl were obtained over the ranges 93-112% (RSD = 1.9-3.6%) and 98-109% (RSD = 1.7-3.8%), respectively. The most probable CL reaction mechanism was explored.

Could manganate be an alternative of permanganate for micropollutant abatement?

Permanganate (MnO4-), an oxidant that has been applied in water treatment, has highly varied reactivity toward pollutants. In this study, we found manganate (MnO42-) could destruct diverse functional groups, with oxidation rates being higher than that of permanganate under acidic and neutral conditions. Mechanistic study revealed manganate rapidly disproportionated to permanganate and colloidal MnO2 in solution. Under acidic conditions, the in-situ formed colloidal MnO2 possess higher reactivity than permanganate and primarily contributed to the degradation of pollutants. The reactivity of in-situ formed colloidal MnO2 is highly sensitive to pH and decreased dramatically with increasing pH. Consequently, the contribution of MnO2 to pollutant removal decreased with elevating pH, which also leads to the decreased degradation efficiency of micropollutants at high pH. Manganate is an intermediate produced during the manufacturing process of permanganate. This study indicates that manganate might be an alternative of permanganate for water purification under acidic and neutral conditions.

Reducing disinfection byproduct precursors through coagulation enhancement as particle weight and size control using potassium permanganate.

The widespread use of chlorine pre-oxidation in water purification has been limited in several countries owing to the production of carcinogenic byproducts when combined with naturally occurring organic matter. This study investigates the efficient use of potassium permanganate (KMnO4) pretreatment and coagulation enhancement as particle size and molecular weight distribution controlling parameters. KMnO4 pretreatment significantly reduced the apparent molecular weight of humic acid due to KMnO4 reduction and the continuous generation of manganese dioxide (MnO2) formed in situ under neutral and alkaline conditions. The MnO2 formed in situ had adsorption characteristics that enabled it to form large and stable flocs with the hydrolysis products of aluminum sulfate. However, under acidic conditions, KMnO4 pretreatment exhibited strong oxidation characteristics due to Mn(VII) reduction to Mn(II), and the mean particle floc size was the same as without KMnO4 pretreatment. Overall, KMnO4 pretreatment is a useful alternative strategy for traditional pre-oxidation using chlorine and a good coagulant enhancement agent in neutral and basic media.

Rediscover Potassium Permanganate as a Stain for Basic Proteins on Ultrathin Sections at Transmission Electron Microscopy.

Potassium permanganate solution has been used both as a fixative and as a staining for ultrathin sections at transmission electron microscopy, due to its ability to provide good contrast of different tissue components. Subsequently, it has been forgotten due to disadvantages such as conspicuous formation of precipitates and fragility of the tissue sections treated with this dye when placed under the electron beam. Here we demonstrate that the observed granularity of the sections is not related to the formation of non-specific precipitates, but rather to basic proteins such as chromatin proteins closely associated with DNA and ribosomal particles which are intensely stained. This results in a marked contrast of the nuclei, in particular of the heterochromatin areas, the granular component of the nucleoli, and the rough endoplasmic reticulum, that are rich in these protein complexes. We also show how the embedding in LR white acrylic resin can preserve a good morphology and be less sensitive to the treatment with potassium permanganate than the epoxy resin sections, also allowing to perform immunocytochemistry. The fragility of the epoxy resin sections can be partially improved by using formvar-coated grids.

Enhanced methane production from anaerobic digestion of waste activated sludge by combining ultrasound with potassium permanganate pretreatment.

The influence of ultrasound (US) and potassium permanganate (KMnO4) co-pretreatment on anaerobic digestion of waste activated sludge (WAS) was investigated in this survey. Results showed that KMnO4 (0.3 g/g TSS) cooperated with US (1 W/mL, 15 min) pretreatment significantly increased the cumulative methane yield to 174.44 ± 3.65 mL/g VS compared to the control group (108.72 ± 2.56 mL/g VS), solo US (125.39 ± 2.56 mL/g VS), and solo KMnO4 pretreatment group (160.83 ± 1.61 mL/g VS). Mechanistic investigation revealed that US combined with KMnO4 pretreatment effectively disrupted the structure of extracellular polymeric substances and cell walls by generating reactive radicals, accelerating the release of organics and hydrolytic enzymes as well as improving the biodegradability of soluble organics. Modeling analysis illustrated that the biochemical methane potential and hydrolysis rate of WAS were enhanced under US + KMnO4 pretreatment. Microbial community distribution indicated that the co-pretreatment of US and KMnO4 elevated the total relative abundance of functional microorganisms associated with anaerobic digestion (22.01 %) compared to the control (10.69 %), US alone (12.24 %) and KMnO4 alone (16.20 %).

Minimising risk of harm from potassium permanganate soaks.

Overview of: British Association of Dermatologists. Guidance on minimising risk of harm from potassium permanganate soaks. April 2022.

Development and application of low-density polyethylene-based multilayer film incorporating potassium permanganate and pumice for avocado preservation.

This study aimed to develop a low-density polyethylene-based multilayer active packaging film with three layers. The core layer was an active layer containing pumice and potassium permanganate, while the skin layer was the barrier layer impregnated with sodium chloride. The multilayer film showed an ethylene scavenging capacity of 1.6 µmol/(25 in2) within 8 d at 25 °C and was endowed with water absorption capacity. In addition, the oxygen and water vapor permeability of the multilayer film were improved in comparison to the neat one. Further, the multilayer film extended the shelf life of avocado from less than 10 d to 16 d at 25 °C, controlled ethylene and carbon dioxide concentrations, and caused a reduction in the loss of flesh firmness and weight. More importantly, according to migration testing, active agents in the core layer would not migrate to avocado peel, which ensured that avocados would not be contaminated.

Design and Fabrication of α-MnO2-Nanorods-Modified Glassy-Carbon-Electrode-Based Serotonin Sensor.

Serotonin is a very important monoamine neurotransmitter, which takes part in biological and psychological processes. In the present scenario, design and fabrication of a serotonin electrochemical sensor is of great significance. In this study, we have synthesized α-MnO2 via a hydrothermal synthesis method using potassium permanganate as a precursor. The physiochemical properties, such as structural and phase-purity of the prepared α-MnO2, were investigated by various characterization techniques and methods (powder X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy). Furthermore, the serotonin sensor was fabricated using α-MnO2 as an electrode modifier or electro-catalyst. The bare glassy carbon electrode (GCE) was adopted as a working substrate, and its active carbon surface was modified with the synthesized α-MnO2. This modified GCE (α-MnO2/GCE = MGCE) was explored as a serotonin sensor. The electrochemical investigations showed that the MGCE has excellent electro-catalytic properties towards determination of serotonin. The MGCE exhibits an excellent detection limit (DL) of 0.14 µM, along with good sensitivity of 2.41 µAµM-1 cm-2. The MGCE also demonstrated excellent selectivity for determination of serotonin in the presence of various electro-active/interfering molecules. The MGCE also exhibits good cyclic repeatability, stability, and storage stability.

Determinação do período de estabilidade de soluções volumétricas rotineiramente utilizadas em laboratórios de análises químicas / Determination of the stability period of volumetric solutions routinely used in chemical analysis laboratories / Determinación del período de estabilidad de las soluciones volumétricas utilizadas habitualmente en los laboratorios de análisis químicos

As soluções volumétricas são rotineiramente utilizadas nos laboratórios, principalmente nos processos de síntese de produtos e nas análises quantitativas de matéria-prima e/ou produto acabado, entretanto poucos são os estudos que abordam a estabilidade destas soluções. Considerando que a qualidade das soluções volumétricas pode afetar os procedimentos de análises químicas e consequentemente induzir a erros, e ainda que, a Farmacopeia Brasileira (2010) não cita tempo máximo de utilização dessas soluções padronizadas, a avaliação da estabilidade das mesmas é importante. Sendo assim, o objetivo do trabalho foi avaliar a estabilidadede 10 soluções volumétricas, empregadas rotineiramente em laboratórios de análises químicas, com o intuito de estabelecer o período que essas soluções permanecem estáveis, isto é, sem sofrer alteração na concentração. As metodologias de preparo e padronização das soluções volumétricas seguiram os métodos descritos na Farmacopeia Brasileira (2010), sendo as mesmas padronizadas no momento do preparo e a cada 20 dias, por um período de 180 dias. As soluções contendo ácidos e bases, bem como as soluções de iodato de potássio e nitrato de prata, permaneceram constantes durante o período de análises. As soluções de EDTA, iodo, nitrito de sódio, permanganato de potássio e tiossulfato de sódio apresentaram estabilidade inferior a 180 dias, tornando necessária a realização de padronização periódica. As soluções volumétricas utilizadas nos laboratórios apresentam diferentes estabilidades, o que ressalta a importância da determinação do período que as mesmas se mantêmcom as concentrações estáveis, evitando possíveis alterações de resultados nas análises químicas.

Volumetric solutions are routinely used in laboratories, mainly in product synthesis processes and in quantitative analyzes of raw materials and/or finished products, however there are few studies that address the stability of these solutions. Considering that the quality of volumetric solutions can affect chemical analysis procedures and consequently induce errors, and even though the Brazilian Pharmacopoeia (2010) does not mention the maximum time for using these standardized solutions, the evaluation of their stability is important. Therefore, the aim of this work was to evaluate the stability of 10 volumetric solutions, routinely used in chemical analysis laboratories, in order to establish the period that these solutions remain stable without changing their concentrations. The methodologies for preparing and standardizing the volumetric solutions followed the methods described in the Brazilian Pharmacopoeia (2010), being standardized at the time of preparation and every 20 days, for a period of 180 days. Solutions containing acids and bases, as well as potassium iodate and silver nitrate solutions, were stable during the analysis period. The solutions of EDTA, iodine, sodium nitrite, potassium permanganate and sodium thiosulfate showed stability less than 180 days, making it necessary to carry out periodic standardization of these solutions. The volumetric solutions used in the laboratories have different stabilities, which highlights the importance of determining the period in which they remain stable, avoiding possible changes in results in chemical analyzes.

Las soluciones volumétricas se utilizan de forma rutinaria en los laboratorios, principalmente en los procesos de síntesis de productos y en el análisis cuantitativo de materias primas y/o productos acabados. Sin embargo, existen pocos estudios que aborden la estabilidad de estas soluciones. Considerando que la calidad de las soluciones volumétricas puede afectar los procedimientos de análisis químico y consecuentemente inducir a errores, y también que, la Farmacopea Brasileña (2010) no menciona el tiempo máximo de uso de estas soluciones estandarizadas, la evaluación de su estabilidad es importante. Así, el objetivo del trabajo fue evaluar la estabilidad de 10 soluciones volumétricas, utilizadas rutinariamente en los laboratorios de análisis químico, con el fin de establecer el período en que estas soluciones permanecen estables, es decir, sin sufrir alteraciones en la concentración. Las metodologías de preparación y estandarización de las soluciones volumétricas siguieron los métodos descritos en la Farmacopea Brasileña (2010), siendo las mismas estandarizadas en el momento de la preparación y cada 20 días, por un período de 180 días. Las soluciones que contienen ácidos y bases, así como las soluciones de yodato de potasio y nitrato de plata, permanecieron constantes durante el periodo de análisis. Las soluciones de EDTA, yodo, nitrito de sodio, permanganato de potasio y tiosulfato de sodio fueron estables durante menos de 180 días, por lo que fue necesario realizar estandarizaciones periódicas. Las soluciones volumétricas utilizadas en los laboratorios presentan diferentes estabilidades, lo que pone de manifiesto la importancia de determinar el periodo que permanecen con concentraciones estables, evitando posibles cambios en los resultados en los análisis químicos.