Instrumental Methods Of Analysis Research Articles

ПЕРСПЕКТИВА ПРИМЕНЕНИЯ ГИБРИДНОГО ПОРОШКОВОГО МАТЕРИАЛА AgI-SiO2 В СОСТАВЕ ПРОТИВОГРАДОВОГО РАКЕТНОГО ТОПЛИВА

The work proposes new hybrid powder materials as sediment-converting reagents used in geoengineering technologies (technologies for artificial precipitation management). Hybrid powder materials AgI-SiO2 are mesophase mesoporous silicon dioxide with silver iodide. They were obtained through the “Paste Formation” process, which involves constant mixing of an aqueous condensed suspension of silicon dioxide of various types with the sequential addition of silver nitrate and potassium iodide. The characteristic features of the synthesized AgI-SiO2 hybrids were studied using instrumental methods of analysis: structural, textural and rheological parameters. The influence of hybrid powder material AgI-SiO2 (HPs) on the efficiency of anti-hail rocket fuel is shown using the TERRA software system for modeling phase and chemical equilibrium at high temperatures. It is certain that using HPs AgI-SiO2 as part of anti-hail rocket fuel leads to an increase in the amount of condensed phase, including active forms of silver iodide. This active form of AgI is required for the implementation of ice formation processes in the cloud. An increase in the amount of the β-form of AgI in the composition of the initial HPs was shown compared to pure silver iodide using X-ray phase (XRF) analysis and differential scanning calorimetry. It was established that silver iodide in the hybrid has greater thermal stability, as evidenced by the characteristic peaks of crystalline forms. HPs AgI-SiO2 will improve the efficiency of anti-hail rocket fuel by increasing the number of ice formation and condensation centers, because they exhibit several mechanisms of action on atmospheric moisture. The synthesized hybrid powders meet the requirements of the regulatory documents in force in the Russian Federation

Возможности инструментального нейтронно-активационного анализа для определения и контроля извлечения скандия из золы ТЭЦ

The possibility of determining the scandium content in ash and slag waste and monitoring the effectiveness of operations in the ash processing by the method of instrumental neutron activation analysis was shown. The scandium content and elemental composition of ash and slag waste from thermal power plants and intermediate products of their processing are presented. An increased content of scandium in the magnetic fraction of ash was established.

FEATURES OF DIAGNOSIS AND TREATMENT OF CROHN’S DISEASE (CLINICAL CASE)

The exact reason for the occurrence of Crohn’s disease remains unknown. It is believed that pathology can be carried out by infectious and viral pathogens, deviations from the norm of natural balance of the microflora of the gastrointestinal tract (hereinafter – the gastrointestinal tract). Many researchers indicate an abnormal autoimmune response of the body on food stimuli – in favor of such an assertion indicates the systematic impression of the internal organs. However, for the emergence and development of this disease, there are significant impacts with harmful habits, such as: smoking, alcoholic beverages and medicines, unbalanced nutrition and the presence of chronic inflammatory gastroids. The inflammatory process begins in the mucous membrane, gradually affects all layers of the wall of the gastrointestinal wall, leads to its destruction and fibrosis and the formation of fistish and stenoses. Therefore, early diagnosis and timely treatment prevents the development of complications, including such severe such as bleeding, perforation of the intestinal wall, intra-abdominal abscesses, internal and external fists, adhesions of the intestine with the development of obstruction. Purpose: on the basis of a specific case of HC to investigate and analyze the features of diagnosis and treatment of these patients using an analytical method and a systematic approach. Materials and methods: The material was a clinical case of HC, methods of instrumental diagnosis and objective analysis. The results: The concrete case of HC is investigated, features of inspection and diagnostics are defined. Conclusions: A feature of the diagnosis and treatment of patients with HC is a constant vigilance about the occurrence of complications, the key to the prevention of which is a multidisciplinary approach in the tactics of diagnosis and treatment of these patients. Key words: Crohn’s disease, features of examination and diagnosis.

Исследование термического превращения мазута в присутствии регенерированного отработанного катализатора гидроочистки

An urgent task of the oil refining industry is the development of a thermodestructive process for the processing of heavy oil residues. This paper presents the results of a study of thermal cracking of fuel oil in the presence of aluminocobaltmolybdenum regenerated spent hydrotreating catalyst. The experiments were carried out using an autoclave, as well as using a number of instrumental methods of analysis. The effect of the degree of dispersity and catalyst content on the results of the process under study was studied. The material balance of the thermal cracking process in the presence of catalyst samples of different fractional composition is compared with the material balance of thermal cracking in the temperature range of 450-470 °C. The physical and chemical properties of the samples of catalysts, raw materials and products of the process were determined. The analysis of the obtained experimental data was carried out, the conditions for the most efficient processing of raw materials in the process of thermal cracking in the presence of a catalyst were determined, and conclusions were drawn about the prospects for its use for processing heavy oil residues.

ПРОГНОСТИЧЕСКИЕ ФАКТОРЫ РИСКА РАЗВИТИЯ ПРЕЭКЛАМПСИИ: СОВРЕМЕННЫЙ ВЗГЛЯД НА ПРОБЛЕМУ. СИСТЕМАТИЧЕСКИЙ ОБЗОР

Significance Preeclampsia is one of the common complications that significantly affects both pregnancy progress and delivery and the newborn health and can be also frequently followed by the death of mother and baby. This substantiates the need to identify risk factors for predicting preeclampsia The purpose of the study was to identify prognostic risk factors of preeclampsia. Material and methods. This systematic review analyzed modern studies on risk factors of preeclampsia and clinical, laboratory and instrumental methods of analysis to identify risk factors of preeclampsia as well as approaches to their assessment. The systematic review was conducted according to the PRISMA guidelines using certain PICO(S) criteria. Results The risk of preeclampsia should be assessed by risk factors to predict preeclampsia early in gestation. To identify such factors in various studies of Russian and foreign authors, the authors analyzed anamnestic factors and results of laboratory and instrumental diagnostic methods. Thus, a history of elevated blood pressure indicates an increased risk of preeclampsia. The highest risk of preeclampsia is registered in pregnant women with antiphospholipid syndrome. Most risk factors of preeclampsia are not potentially avoidable, except for excessive weight gain during pregnancy and multiple pregnancies, such as IVF. According to some researchers, the determination of laboratory parameters (platelet count, creatinine level, liver enzymes and urine protein) can help to predict preeclampsia. Changes in the absolute levels of angiogenic proteins of ischemic trophoblast VEGF, PlGF, sFlt-1, and sEng in mother’s blood and urine not only precede the onset of preeclampsia by several weeks or months, but also correlate with the disease severity and normalize after the delivery, suggesting a high prognostic value of this risk factor. Meta-analyses show that Doppler assessment of blood flow in uterine arteries can predict the risk of preeclampsia. Conclusion. As prognostic risk factors for preventive measures, with a high degree of probability the following set of data should be evaluated: arterial hypertension, antiphospholipid syndrome, obesity, multiple pregnancy, the history of assisted reproductive technologies, assessment results of blood flow in the uterine arteries, some laboratory blood parameters. The search for new predictive risk factors of preeclampsia requires further research.

Key Indicators of a Complex Economic System Forecast

One of the necessary components in the tasks of improving business efficiency is the forecasting of key indicators of economic activity. A large number of different indicators are complex related, and the result of a change in a single indicator or group entails changes in other indicators, which is typical for a large enterprise. The purpose of the work is to propose methods and analytical tools for forecasting key indicators of a complex economic system. A hybrid approach to forecasting a complex economic system has been developed which makes it possible to forecast individual technical and economic indicators, taking into account the dynamics and trends in the entire set of indicators reflecting various aspects of the enterprise's activities. The proposed methodology combines several approaches and contains a number of limitations. At the first stage, a complex system of indicators is decomposed into groups. For each group of indicators, systems of simultaneous equations of multiple regression are determined. Next, the selection of regression models is carried out using regression statistics and economically justified restrictions. Regression models for each indicator are complemented by adaptive model. Synthesis of the result is obtained as a moving average of the forecast. The proposed instrumental methods of analysis are recommended as analytical tools for business analysis for various purposes. Approbation of the proposed analytical forecasting tools according to official reporting data was carried out on a case study of estimating the cost of three large industrial enterprises of the sugar industry in the Volga Federal District.

К вопросу идентификации состава жировой фазы масложировой продукции

Trans-fatty acids enter the human body with hydrogenated fats. The oil and fat industry must inform consumers about the fatty acid composition of food products, including the content of saturated fatty acids and trans-isomers. This study used the method of instrumental analysis to determine the fatty-acid profile and the content of trans-fatty acids in margarine.
 The research involved ten commercial samples of margarine. The fatty acid composition was studied by gas chromatography and mass spectrometry. The calibration graphs were based on standard mixes of methyl esters of individual fatty acids. 
 Some oils appeared to contain ≥ 17% of palmitic acid. The total content of saturated fatty acids was 20.04–38.84%; the content of monounsaturated acids ranged from 27.92 to 36.81%, while that of polyunsaturated acids was between 14.51 and 28.99%. The margarine samples contained no butter (dairy) fat. All the samples contained 0.01–23.06% of trans-fatty acids. If the share of trans-fats exceeded 2%, it meant that the technical regulations had been violated, and hydrogenated oils had been introduced into the formulations.
 The highly specific mass spectrometric approach made it possible to detect trace trans-fatty acids, thus eliminating the chance of unreliable or false positive results. These methods proved to be an effective means of regulatory compliance and counterfeit prevention.

ОСОБЛИВОСТІ ВПЛИВУ ЕПОКСИДОВАНОЇ СОЄВОЇ ОЛИВИ НА ВЛАСТИВОСТІ ПОЛІЛАКТИДНИХ МАТЕРІАЛІВ

Polylactide composite materials with the plasticizer-compatibilizer epoxidized soybean oil, which are filled with organic filler starch and inorganic – calcium carbonate, have been developed. Based on instrumental methods of analysis, the influence of epoxidized soybean oil on the features of physicochemical interactions in the system was investigated. A change in the rheological and thermophysical properties of the developed polylactide materials was established depending on the component composition.

Influence of Ammonia Concentration on Solvay Soda Process Parameters and Associated Environmental and Energetic Effects

Modifying the absorption process in soda production by the Solvay method requires performing many calculations and determining a new equilibrium process. An increase in ammonia concentration in the reaction solution causes kinetic changes in equilibrium. Changes to the Solvay soda production technology were determined using chemical and instrumental analysis methods. A modification of the process in the form of SAB was introduced. Information allowing the design of an additional absorber and its location in the network of technological devices was presented in the form of parameters using typical chemical engineering assumptions. Spectroscopic and electrochemical techniques were used for this purpose. The increase in total alkalinity due to the addition of ammonia to 135 mmol·20 cm−3 resulted in cooling savings of about 152.4 MJ·Mg−1 of soda. The ammonia desorption rate and process energy parameters were determined for the new system. The temperature requirements for the carbonation column were defined, and in particular, a technique was developed to minimize the cooling of the lower part of the reactor, which reduces the consumption of process energy. Emissions of CO2 were reduced from 11.70 to 7.85% and NH3 from 5.52 to 4.89% in exhaust gases from the carbonation column.

Development and Characterization of PEGDA Microneedles for Localized Drug Delivery of Gemcitabine to Treat Inflammatory Breast Cancer.

Inflammatory breast cancer (IBC) is one of the most belligerent types of breast cancer. While various modalities exist in managing/treating IBC, drug delivery using microneedles (MNs) is considered to be the most innovative method of localized delivery of anti-cancer agents. Localized drug delivery helps to treat IBC could limit their adverse reactions. MNs are nothing but small needle like structures that cause little or no pain at the site of administration for drug delivery via layers of the skin. The polyethylene glycol diacrylate (PEGDA) based MNs were fabricated by using three dimensional (3D) technology called Projection Micro-Stereo Lithography (PµSL). The fabricated microneedle patches (MNPs) were characterized and coated with a coating formulation comprising of gemcitabine and sodium carboxymethyl cellulose by a novel and inventive screen plate method. The drug coated MNPs were characterized by various instrumental methods of analysis and release profile studies were carried out using Franz diffusion cell. Coat-and-poke strategy was employed in administering the drug coated MNPs. Overall, the methods employed in the present study not only help in obtaining MNPs with accurate dimensions but also help in obtaining uniformly drug coated MNPs of gemcitabine for treatment of IBC. Most importantly, 100% drug release was achieved within the first one hour only.

Suberinic Acid Isolation from Birch Outer Bark and their Characterization

Global sustainability challenges prompt the world to modify their strategies and shift from a fossil-fuel-based economy to a bio-resources-based one and to the production of renewable biomass-based chemicals. Different processes exist that allow the transformation of raw biomass into desirable bio-based products and/or energy. Depolymerized suberinic acids (SA) can be considered as an alternative resource to different feedstocks for value-added product obtaining, for example to develop bio-polyols that can be further used in polymeric material production. Birch outer bark was used as a raw material for obtaining SA and was extracted with ethanol to remove extractives. Further extracted birch outer bark was depolymerized with potassium hydroxide ethanol/methanol/n-butanol/2-propanol solutions. Obtained SA suspension was dried by performing lyophilization or by drying at 100 °C. As a result, we obtained 8 SA samples, which were characterized using chemical (total phenolics content, solubility in DMSO, acid number, hydroxyl number, and saponification number) and instrumental analytical methods (GC-MS, SEC-RID, FTIR). The most suitable SA for obtaining value-added product, such as bio-polyol, were obtained by using ethanol as a solvent for depolymerization process. The corresponding SA had the best results in terms of dry matter content, yield, solubility in DMSO, epoxy groups, acid number and ash content. After GC-MS results it was concluded that the amount of diacids, hydroxyacids and extractives are dependent of the used alkanol for SA depolymerization as well as the drying method.

Current analysis strategies of polychlorinated naphthalenes in soil and their application in occurrence and distribution investigation: A mini-review

As a new kind of persistent organic pollutants, polychlorinated naphthalenes (PCNs) have been paid much attention owing to the environmental and health hazards. Several countries have announced moves to intensify its battle against these new pollutants to improve environmental protection. Due to the matrix complexity of soil and the low-level of targets, PCNs analysis requires ongoing development to improve the sensitivity and accuracy. The effective extraction technique that allows for their separation from interfering substances and sensitive analysis instrument that possesses low detection limits are all important parts for the analytical procedure. This review focused on the dissemination of the latest advances covering sample pretreatment and instrumental analysis methods, followed by their application in investigating the occurrence and homologues distribution of PCNs in soil. It will help readers quickly understand the PCNs analysis methods, and choose the appropriate one according to their objects and laboratory conditions, which may conduce to the supervision and treatment of new pollutions.

New composite membranes based on PVDF fibers loaded with TiO2: Sm nanostructures and reinforced with graphene/graphene oxide for photocatalytic applications

New composite membranes based on PVDF fibers loaded with Sm doped TiO2 (TiO2:Sm) nanostructures and graphene-based nanoparticles obtained by the electrospinning technique are reported. The addition of the inorganic nanostructures induced photocatalytic properties, while the graphene-based nanoparticles (G - graphene or GO - graphene oxide) improved the mechanical properties. Advanced instrumental methods for material analysis (e.g., XRD, SEM, mechanical, and DVS) were employed to characterize the structure and surface properties. The membranes were used in photocatalytic assays for the degradation of methylene blue (MB) under visible light irradiation. To intensify the photocatalytic processes, the effect of hydrogen peroxide addition was also investigated. The results revealed that the PVDF-based membrane containing 15% TiO2:Sm and 2.5% GO showed an optimal photocatalytic activity due to its high porosity, relevant adsorption capacity, and improved mechanical properties. The response surface methodology was employed to optimize the experimental conditions of the photocatalytic process. The addition of H2O2 significantly increased the rate constant of photodegradation reaction (k = 6.624× 10−1 min−1), disclosing a half-life of the reaction of about 1 min. This short half-life time represents a remarkable outcome for a photocatalytic process conducted under visible light irradiation. Good recycling capacity was observed for the optimal (TiO2:Sm)[15%]/PVDF/GO[2.5%] composite membrane.

Quantitative Analyses of Biofilm by Using Crystal Violet Staining and Optical Reflection.

Biofilms have caused many problems, not only in the industrial fields, but also in our daily lives. Therefore, it is important for us to control them by evaluating them properly. There are many instrumental analytical methods available for evaluating formed biofilm qualitatively. These methods include the use of Raman spectroscopy and various microscopes (optical microscopes, confocal laser microscopes, scanning electron microscopes, transmission electron microscopes, atomic force microscopes, etc.). On the other hand, there are some biological methods, such as staining, gene analyses, etc. From the practical viewpoint, staining methods seem to be the best due to various reasons. Therefore, we focused on the staining method that used a crystal violet solution. In the previous study, we devised an evaluation process for biofilms using a color meter to analyze the various staining situations. However, this method was complicated and expensive for practical engineers. For this experiment, we investigated the process of using regular photos that were quantified without any instruments except for digitized cameras. Digitized cameras were used to compare the results. As a result, we confirmed that the absolute values were different for both cases, respectively. However, the tendency of changes was the same. Therefore, we plan to utilize the changes before and after biofilm formation as indicators for the future.

Developing colloidal structure of beer by grain organic compounds

The present article introduces the problem of determining the general structure of beer as a complex system of related biomolecules. The objective was to establish the correlation of various quantities of organic compounds in beer formulation.
 The research featured samples of filtered pasteurized beer obtained from a retail chain shop in Moscow (Russia). The experiment relied on standard research methods, including instrumental methods of analysis, e.g., high-performance liquid chromatography (HPLC). The obtained experimental data underwent a statistical analysis using the Statistica software (StatSoft, 2016). 
 The research established the correlation between the type of grain (barley or wheat malt) and the content of organic compounds, e.g., β-glucan, polyphenols, soluble nitrogen, etc. The research also revealed some patterns in the distribution of proteins, which served as a framework for the system of organic compounds. The distribution of thiol proteins proved to depend on the dissolution degree of the grain and was different in barley light, barley dark, and wheat malt samples. The fraction distribution of β-glucan depended on the color of the malt. In light beer samples, it concentrated in high- and medium-molecular fractions of nitrogenous substances, in dark beer – in low-molecular fractions (≤ 63%). Initial wort density and alcohol content affected the amount of catechins and total polyphenols. Nitrogenous compounds depended on the color, initial extract, and alcohol content. 
 The nitrogenous structure and other organic compounds of beer proved to depend on protein substances. The research also revealed a number of factors that affected the fraction distribution of biomolecules in different beer sorts.

P034 Non-conventional alternatives to prevent Candida auris infections

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMObjectives Candida auris represents a particular organism associated with multiple nosocomial infections and high mortality rates. Appropriate infection control measures play a major role in controlling the spread and multiplication of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris. Chlorine-based products appear to be the most effective for inanimate surface disinfection, while iodine-based products are more suitable for skin antisepsis. C. auris has been demonstrated to survive on dry and moist surfaces for up to 14 days, so environmental cleaning to eliminate a source of nosocomial infections is a challenge. Thus, searching for new effective fungicidal agents is still a hot topic nowadays. Non-thermal plasma-activated water (PAW) has recently emerged as a powerful antimicrobial agent, but no data about its effectiveness on C. auris are available. The aim of our study was to assess the possibility of using PAW as a fungicidal agent against C. auris planktonic cells.MethodsPAW was prepared using distilled water and a GlidArc reactor as previously described1. The final parameters of PAW were as follows: conductivity 446 ± 25 μS/cm, pH 2.78 ± 0.12, redox potential (ORP) + 1.06 V, NO2 192 ± 10 mg/L, NO3 1550 ± 95 mg/L, H2O2 2.6 ± 0.12 mg/L, and O3 1.08 ± 0.07 mg/L.A type strain of C. auris (CBS 10913) was used in this study. Suspensions of yeast cells (107 CFU/ml) were prepared from overnight cultures and subsequently treated with PAW in a ratio of 1:10 for different periods of time (1, 3, 5, 7, 10, 15, and 20 minutes). Precise volumes of the mixtures were further inoculated on Sabouraud Dextrose Agar plates and Bact/Alert FA Plus bottles (bioMerieux, France) in order to evaluate the reduction of yeast burden after each contact period. In addition, some instrumental analysis (IA) methods were used in order to assess the impact of PAW treatment on yeast cell structure: Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectrometry (FT-IR), and Dynamic Light Scattering (DLS). All tests were performed in triplicates.ResultsA reduction higher than 5 log10 of viable yeast was achieved in 3 minutes. The sterilization level (i.e., ˃6 log10 reduction) was achieved after 5 minutes for the tested strain. IA clearly objectified the morphological changes in the treated yeasts compared with the untreated ones (Figs. 1 and 2).ConclusionOur research has successfully demonstrated the fungicidal effect of PAW against C. auris, opening a new field of research in the area of disinfectants.1. Valentin Nastasa, Aurelian-Sorin Pasca, Razvan-Nicolae Malancus, Andra-Cristina Bostanaru, Luminita-Iuliana Ailincai, Elena-Laura Ursu, Ana-Lavinia Vasiliu, Bogdan Minea, Eugen Hnatiuc, Mihai Mares, [2021] - Toxicity Assessment of Long-Term Exposure to Non-Thermal Plasma Activated Water in Mice, Int. J. Mol. Sci., 22(21), 11 534; https://doi.org/10.3390/ijms222111534.

Instrumental analysis of the impact of economic factors on the level of a country’s economic innovativeness

The rapid development of innovative activity in Ukraine and the instability of the economic and political environment determine the relevance of studying the problems of innovative development in close connection with global and local factors of economic growth. The purpose of the research is to study the budgetary policy factors that have a dominant influence on the level of national innovative development, and their impact on the level of economic growth in order to form directions for innovation policy development based on instrumental analysis methods. The paper uses methods of econometric modeling and adaptive methods of forecasting. The constructed conceptual model includes three aggregated stages of research. The study addressed the problem of assessing the level of a country’s economic innovativeness and determining the factors affecting it; it was found that this level grows with an increase in the share of private investment, a decrease in the rate of GDP growth, an increase in the share of taxes in the budget structure, a decrease in the money supply, an increase in education and public security expenditures. The impact of the state budgetary policy was analyzed and the value of the indicator of economic growth and the level of the country’s economic innovativeness was forecasted. The practical significance of the results is that a gradual reduction in the level of the country’s economic innovativeness is possible in periods of long-term economic growth. To avoid such negative consequences, European governments should pay more attention to internal problems and external trends of innovation activity

Anticancer activity of an Artemisia annua L. hydroalcoholic extract on canine osteosarcoma cell lines

Since ancient times, Artemisia annua (A. annua) has been used as a medicinal plant in Traditional Chinese Medicine. In addition, recent studies have investigated the cytotoxic effects of A. annua extracts towards cancer cells. The leading aim of the present research is to evaluate the cytotoxic effects of an hydroalcoholic extract of A. annua on two canine osteosarcoma (OSA) cell lines, OSCA-8 and OSCA-40, focusing on the possible involvement of ferroptosis.The quantitative determination of artemisinin concentration in the extract, culture medium and OSA cells was carried out through the use of an instrumental analytical method based on liquid chromatography coupled with spectrophotometric detection and tandem mass spectrometry (LC-DAD-MS/MS). OSCA-8 and OSCA-40 were exposed to different dilutions of the extract for the EC50 calculation then the uptake of artemisinin by the cells, the effects on the cell cycle, the intracellular iron level, the cellular morphology and the lipid oxidation state were evaluated. A concentration of artemisinin of 63.8 ± 3.4 μg/mL was detected in the extract. A dose-dependent cytotoxic effect was evidenced. In OSCA-40 alterations of the cell cycle and a significantly higher intracellular iron content were observed. In both cell lines the treatment with the extract was associated with lipid peroxidation and with the appearance of a “ballooning” phenotype suggesting the activation of ferroptosis. In conclusion the A. annua idroalcoholic extract utilized in this study showed anticancer activity on canine OSA cell lines that could be useful in treating drug resistant canine OSAs.

Nontoxic Enantiomeric Reference Materials for Saxitoxins.

Saxitoxin (STX) is a potent neurotoxin that is biosynthesized by toxic dinoflagellates and accumulated in shellfish via the food chain. STX and its various analogues are now monitored in shellfish by the hygiene authorities in many countries with instrumental analytical methods, which require calibration with standards. Unfortunately, STX is registered as a chemical warfare agent in Schedule 1 of the Chemical Weapons Convention, and this has made it difficult to import calibration standards into some countries. We aimed to avoid violation of the Chemical Weapons Convention and facilitate analyses by preparing calibration standards based on unnatural nontoxic antipodal STXs (ent-STXs) with the same physicochemical properties as natural STXs. Our findings demonstrate that the nontoxic ent-STXs can be safely utilized as alternative reference materials of STXs in the routine monitoring program by the local authorities and consequently can lead to reduced usage of STX.

An Investigation into the Adsorption Mechanism of Organic Anions on a New Spandex.

In recent years, there has been significant interest in the study of spandex in high-elasticity sensors. As a new kind of special spandex, dyeable spandex shows strong adsorption capacity for anions. In this study, neutral red G was used as an anion adsorption simulator to study the adsorption mechanism of dyeable spandex on anionic materials. The structure of dyeable spandex was characterized by the modern instrumental analysis method, and the adsorption kinetics and thermodynamics of neutral red G on dyeable spandex were discussed. The results show that the use of mixed amines as chain extenders for dyeable spandex reduced the regularity of molecules and the crystallinity of spandex, which was beneficial to the diffusion adsorption of anions. On the other hand, the number of secondary amino groups increased, providing more adsorption sites under acidic conditions. The adsorption of neutral red G on dyeable spandex satisfied the quasi-second-order kinetics and the Langmuir adsorption model, indicating that dye adsorption on spandex was mainly electrostatic. The diffusion coefficient and equilibrium adsorption capacity of neutral red G on dyeable spandex increased significantly, whereas enthalpy and entropy decreased.