Effect Of Buffer Solutions Research Articles

First Voltammetric Determination of Karbutylate via Pencil Graphite, Glassy Carbon, and Boron-Doped Diamond Electrodes in Soil Sample

We investigated the electrochemical behavior of carbamate pesticide-type karbutylate (KB) with boron-doped diamond (BDD), glassy carbon (GC), and pencil graphite (PG) electrode, and analytical determination in real samples. Similar to organophosphate insecticides, carbamate pesticides are produced from carbamic acid and are extensively utilized in agriculture, gardens, and residences. Therefore, a rapid and simple detection of KB in real samples is important. Carbon-based electrodes are widely used in electroanalytical chemistry due to their rich surface chemistry, chemical inertness, broad potential window, low background current, and congruency for various demanding applications. Three different carbon-based electrodes were used. The effect of buffer solutions, scan rate, square wave (SWV), and differential pulse voltammetry parameters on the voltammetric response of KB was tested. The optimum working media for all three electrodes was determined as pH 2.00 phosphate buffer solution and voltammetric measurements were carried out in this media. Under optimum experimental conditions, linear calibration dependences for KB were obtained as 6.00 × 10−7–8.00 × 10−5 M, 4.00 × 10−7–8.00 × 10−5 M, and 8.00 × 10−8–8.00 × 10−5 M with a limit of detection of 2.18 × 10−7, 3.71 × 10−8 M, and 2.66 × 10−8 M by the BDD, GC, and PG electrodes, respectively, using SWV. As a result, sensitive determination of KB has been successfully performed using different carbon-based electrodes in real soil samples.

Electrochemical sensor for the analysis of 5-hydroxymethylcytosine in the presence of cytosine using pencil graphite electrode

In recent years, important efforts have been made to elucidate the mechanisms of epigenetic regulation, and one of the most studied epigenetic modifications was DNA methylation/demethylation. In this study, the voltammetric behaviour of 5-hydroxymethylcytosine was studied in the pH range of 2.00–11.00 using pencil graphite electrodes by differential pulse and square wave voltammetry. The effect of buffer solutions, scan rate, square wave voltammetry parameters, and stripping conditions on the voltammetric responses of 5-hydroxymethylcytosine were performed. The electrochemical oxidation process of 5-hydroxymethylcytosine on the pencil graphite electrode was realized under adsorption control. In human urine, by square wave stripping voltammetry, 5-hydroxymethylcytosine was quantified in a concentration range of 1.00 × 10−5 M-2.00 × 10−4 M. The proposed method was tested in the presence of cytosine in human urine. The recovery value of 5-hydroxymethylcytosine was found to be 99.57 %.

A Light-Powered In Vitro Synthetic Enzymatic Biosystem for the Synthesis of 3-Hydroxypropionic Acid via CO2 Fixation.

3-Hydroxypropionic acid (3-HP) is a highly sought-after platform chemical serving as a precursor to a variety of high value-added chemical products. In this study, we designed and constructed a novel light-powered in vitro synthetic enzymatic biosystem comprising acetyl-CoA ligase, acetyl-CoA carboxylase, malonyl-CoA reductase, and phosphotransferase to efficiently produce 3-HP through CO2 fixation from acetate, a cost-effective and readily available substrate. The system employed natural thylakoid membranes (TMs) for the regeneration of adenosine triphosphate and nicotinamide adenine dinucleotide phosphate. Comprehensive investigations were conducted on the effects of buffer solutions, substrate concentrations, enzyme loading levels, and TMs loading levels to optimize the yield of 3-HP. Following optimization, a production of 0.46 mM 3-HP was achieved within 6 h from an initial 0.5 mM acetate, with a yield nearing 92%. This work underscores the simplicity of 3-HP production via an in vitro biomanufacturing platform and highlights the potential for incorporating TMs as a sustainable and environmentally friendly approach in biomanufacturing processes.

Study of the biological activity of pyrazoline derivatives with fusidic acid and ZnO as an antibacterial and antioxidant

pyrazoline was synthesized as a derivative, then the polymerization of pyrazoline was carried out with fusidic acid and zinc oxide. All the physical properties affecting the construction process, such as Thin-layer chromatography, solubility, the effect of buffer solutions, and temperatures, were studied. Physical diagnostics such as DSC, TGA, and FT-IR were also investigated. The study of the biological activity of the polymer resulting from the interaction of pyrimidine with fusidic acid and zinc oxide, where the study was conducted against three types of bacteria, and the results of the study were compared with the activity of fusidic acid alone once and with zinc oxide alone again as a control. The results showed that the process of polymerization of pyrazoline with fusidic acid and zinc oxide gives more excellent results against bacteria compared to fusidic acid alone and zinc oxide alone.

Эффективность использования солевого раствора при искусственном осеменении икры радужной форели Oncorhynchus mykiss (Waibaum, 1972) и ладожской палии Salvelinus alpinus lepechini (Gmelin, 1788)

In order to increase the level of fertilization of eggs, the effect of buffer solution on sperm activity and the effectiveness of its use as a medium for insemination eggs of rainbow trout which was grown in conditions of flowing water and in recirculation aquaculture system (RAS), as well as Ladoga palia, were tested. In male trout and palia, the number of motile spermatozoa and their activity were higher in solution than in water. In trout which was grown in running water, the percentage of eggs fertilization increased significantly when use solution only in cases when the eggs were contaminated with the contents of burst eggs. In fish grown in the RAS, the replacement of water with a buffer solution increased the level of fertilization in all test variants, regardless of the presence or absence of contamination of the eggs. In Ladoga palia, the result of insemination was the same in water and in solution.

Effect of Buffer Solution on the Detection of Cu(II) by Graphite Carbon Nitride Modified Electrode

Effect of Buffer Solution on the Detection of Cu(II) by Graphite Carbon Nitride Modified Electrode

Enhanced buffer capacity of fermentation broth and biohydrogen production from corn stalk with Na2HPO4/NaH2PO4

The remarkable buffer capacity of buffer solution can significantly improve the biohydrogen production yield and energy conversion efficiency. In the present study, the effect of buffer solution Na2HPO4/NaH2PO4 on buffer capacity of fermentation broth and photo-fermentation biohydrogen production (PFHP) was studied. Gas characteristics, fermentation broth properties, and kinetic parameters in PFHP were investigated. With the increase in pH values (5–7) of buffer solution Na2HPO4/NaH2PO4, firstly hydrogen yield increased and then decreased. Maximum energy conversion efficiency 9.84%, hydrogen yield 132.69 mL/g corn stalk, and hydrogen content 53.88% were achieved at pH value of 6. The results of one-way ANOVA showed that pH values of fermentation broth and cumulative hydrogen production were strongly affected by pH values of buffer solution. Buffer solution Na2HPO4/NaH2PO4 retarded the decrease of pH value of photo-fermentation broth, and significantly improved the PFHP.

Ozonation for Degradation of Acid Red 14: Effect of Buffer Solution

The efficiency of ozonation for the removal of color from textile azo dye solution containing Acid Red 14 by ozone was studied. The effect of ozonation time on the decolorization of azo dye has been examined, and the results were analyzed in terms of color removal efficiency. The high color removal efficiency of 93% was obtained after 25 min of ozonation. The effect of buffer solution on the ozonation was also studied, and the results demonstrated in terms of treatability effect for the removal of color from azo dye solutions.

Two-Dimensional Array ATP/ADP Sensitive Image Sensor with a Uniform Distribution of Chemically Immobilized Apyrase

Abstract ATP and ADP are the major energy source in metabolism of cells, and furthermore ATP works as an important extracellular signaling material. ATP bioimaging is required to understand their metabolism. In this paper, a label-free ATP/ADP image sensor was fabricated using a 128 × 128 (16 k) pixel array semiconductor CCD-type pH image sensor and Apyrase. The principle is based on measuring protons produced by the enzyme reaction between Apyrase and ATP or ADP. In order to put a uniform potential response of the sensor into practice, two different methods, (3-APTES and CEST), which chemically fixed N-terminal of Apyrase with the sensor were examined. The sensor modified by the CEST method had a quite clean surface microscopically and demonstrated a fine real-time image monitoring the ATP concentration. The potential response of the image sensor was characterized; effect of buffer solution, calibration curves of ATP and ADP, durability, the limit of detection (LOD) for ATP, and the response of time. The potential distribution for effective pixels to ATP concentration was narrow, single and symmetrical. Due to 16 K sensing pixels finely responding to ATP concentration uniformly, the LOD of ATP concentration (10 µM) was exactly determined with a statistical treatment.

Influence of buffer solutions in the adsorption of human serum proteins onto layered double hydroxide

The adsorption of human immunoglobulin G (IgG) and human serum albumin (HSA) on a non-calcined Mg-Al layered double hydroxide (3:1 Mg-Al LDH) was studied in batch and fixed bed experiments, focusing on the effect of buffer solution and pH over sorbent uptake. Mg-Al LDH was synthesized and characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherms at −196°C, X-ray photoelectron spectroscopy (XPS), Zero point charge (pHzpc), particle size distribution and Fourier transform infra-red (FTIR). Batch adsorption experiments were performed in order to investigate the effects of pH on IgG and HSA adsorption with different buffers: sodium acetate (ACETATE), sodium phosphate (PHOSPHATE), 3-(N-morpholino) propanesulfonic acid (MOPS), 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES) and trizma-hydrochloric acid (TRIS-HCl). Maximum adsorption capacities estimated by the Langmuir model were 239mgg−1 for IgG and 105mgg−1 for HSA in TRIS-HCl buffer. On the other hand, the highest selectivity for IgG adsorption over HSA was obtained with buffer PHOSPHATE (pH 6.5). The maximum IgG and HSA adsorption uptake in this case were 165 and 36mgg−1, respectively. Fixed bed experiments were carried out with both proteins using PHOSPHATE buffer (pH 6.5), which confirmed that IgG was more selectively adsorbed than HSA on Mg-Al LDH and both could be fully recovered by elution with sodium chloride (NaCl).

Ferric iron enhanced chloramphenicol oxidation in pyrite (FeS2) induced Fenton-like reactions

Abstract In this study, the novel combination of Fe 3+ and FeS 2 /H 2 O 2 system was used to enhance the degradation of chloramphenicol (CAP) by promoting the synergetic effect between the Fe 3+ and the FeS 2 , and the kinetic models to elucidate the reaction mechanisms were validated. Raw pyrite samples were pretreated and characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy and Brunauer–Emmett–Teller surface area analyzer. Studies on the effects of buffer solution and phosphate on the kinetics of CAP degradation revealed that the autocatalytic effect was associated with the dissolution and generation of Fe 3+ . As confirmed by the experiment to examine the Fe 3+ mediated oxidation of FeS 2 , the catalytic improvement was due to the release of Fe 2+ by the reaction between the FeS 2 and the Fe 3+ at zero-order rate when the Fe 3+ was excessively present. Kinetic models including surface-controlled activation and homogeneous Fenton reactions were responsible for the degradation of CAP.

Reversed Phase Monolithic Column Based Enzyme Reactor for Protein Analysis

Abstract We developed a reversed-phase monolithic column based enzyme reactor for protein analysis. The effects of buffer solution, porous structure of the column, digestion time and hydrophobicity of solid phase on the digestion performance of enzyme reactor were systematically investigated in terms of the number of identified unique peptides, sequence coverage and the level of missed cleavage as the evaluation indicators. The results demonstrated that the reversed-phase monolithic column based enzyme reactor had high digestion efficiency and might be further extended to the proteome analysis of complex samples.

Oxidative Decarboxylation of Levulinic Acid by Silver(I)/Persulfate

The oxidative decarboxylation of levulinic acid (LA) by silver(I)/persulfate [Ag(I)/S2O82−] has been investigated in this paper. The effects of buffer solution, initial pH value, time and temperature and dosages of Ag(I)/S2O82− on the decarboxylation of LA were examined in batch experiments and a reaction scheme was proposed on basis of the reaction process. The experimental results showed that a solution of NaOH-KH2PO4 was comparatively suitable for the LA decarboxylation reaction by silver(I)/persulfate. Under optimum conditions (temperature 160 °C, pH 5.0, and time 0.5 h), the rate of LA conversion in NaOH-KH2PO4 solutions with an initial concentration of 0.01 mol LA reached 70.2%, 2-butanone (methyl ethyl ketone) was the single product in the gas phase and the resulted molar yield reached 44.2%.

Different DNA Immobilization Strategies for the Interaction of Anticancer Drug Irinotecan with DNA Based on Electrochemical DNA Biosensors

The interaction of anticancer drug irinotecan (CPT-11) which is the inhibitor of the Topoisomerase I enzyme, with fish sperm double stranded deoxyribonucleic acid (dsDNA) and synthetic short oligonucleotides were studied electrochemically based on the oxidation signals of guanine and CPT-11 by using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) at pencil graphite electrode (PGE). In this work, three types of methods such as adsorption, covalent attachment and electrostatic binding were used for the immobilization of DNA onto the PGE surface. It is found that an effective modification method for DNA on the electrode surface is very important because it shows an effect on the drug and DNA interaction. As a result of the interaction, the electrochemical signal of guanine and CPT-11 greatly decreased. Experimental parameters, such as the effect of buffer solution on the interaction between CPT-11 and DNA, the concentration of CPT-11/DNA, the immobilization time of DNA and the accumulation time of CPT-11 were studied in DPV; in addition, the interaction of CPT-11 with oligonucleotides was evaluated for use as a hybridization indicator in CV and DPV. The detection limit and the reproducibility were also determined.

Biosensor for atrazin based on aligned carbon nanotubes modified with glucose oxidase

A sensitive method was developed for the determination of the hebicide atrazine. It based on the use of glucose oxidase that is self-assembled on aligned carbon nanotubes on the surface of a copper electrode. The surface morphology and electrochemical properties of the electrode were characterized by field emission scanning electron microscopy and cyclic voltammetry. The effects of buffer solution and incubation time on the response of the electrode were investigated. Response to atrazine is linear in the range from 0.58 µM to 42 µM, and the detection limit is 39 nM. The performance of the biosensor was verified by determination of atrazine in environmental water samples.

Effect of Buffer Solutions on the Flow and Fracture in Calcite

K1c Values that are environment – sensitive were obtained. Flow and fracture resulting from Vickers indentation testing of {100} have been studied. Plastic flow occurred in calcite; they are anisotropic and environment - sensitive. Fracture in calcite occurred in lateral, median, and subsurface models. Meyer’s indices were determined and they also are environment – sensitive, they were found to be n < 2.

Studies on the Effects of Additional Components on Micellization of CTAB via Surface Tension Measurements

The effects of Tris-HCl buffer solution on the cmc of cetyltrimethylammonium bromide (CTAB) were studied by surface tension measurement. The result shows that the effect of the buffer solution depends on the interaction between CTAB and NaCl and the structure accelerants of water, Tris. A series of parameters, including the critical micelle concentration (cmc), the surface tension at cmc (γcmc), the adsorption efficiency (pC20), and the effectiveness of surface tension reduction (∏cmc) were obtained from the surface tension measurements in the presence of glycine with different concentration in the Tris-HCl buffer solution at 27°C. In addition, maximum surface excess concentration (Γ max) and minimum surface area per molecule (Amin) at the air-water interface were estimated according to the Gibbs adsorption isotherm. The thermodynamic parameters (Δ C p,m , Δ H m,tr , Δ C p,m,tr ) of micellization for CTAB in the absence and presence of glycine at different temperature were also been obtained.

Effect of Buffer Solution and Temperature on the Stability of Penicillin G

The effect of medium, molar ratio of buffer to penicillin G sodium, pH, and temperature on the stability of penicillin G sodium was investigated. The stability of penicillin G sodium in various media is in the order of: citrate buffer > acetate buffer > phosphate buffer > sodium bicarbonate > 0.9 % NaCl and 5 % glucose. In the case of the citrate buffer, to maintain stability for a long time, the molar ratio should be higher than 0.75. The degradation kinetics of penicillin in citrate buffer was determined over a pH range of 4.0 to 10.0 and temperatures from (5 to 50) °C. By plotting the data of log k versus pH at constant temperature, V-shaped curves were obtained with a minimum around pH 7.0. The plots of ln k versus 1/T at constant pH are linear, and the lines at all pH values are almost parallel to each other. By fitting to the Arrhenius equation, the activated energy obtained is 83.5 kJ·mol−1·K−1. The best condition to maintain reasonable stability of penicillin G sodium is using the citrate buffer s...

Portable capillary electrophoresis system with potential gradient detection for separation of DNA fragments

A portable capillary electrophoresis (CE) system with a novel potential gradient detection (PGD) was utilized to separate DNA fragments. For the first time it was demonstrated that separation of DNA fragments in polymer solution could be detected by a portable CE system integrated with PGD, with a limit of detection (LOD) comparable to that of the CE-ultraviolet (UV) method. Effects of buffer solution, sieving medium, and applied voltage were also investigated. The portable CE-PGD system shows several potential advantages, such as simplicity, cost effectiveness, and miniaturization.

Investigation of the effect of various buffer solutions used for microinjection of gene-engineering constructs on preimplantation development of mouse embryos

We studied the effects of some buffer solutions used for microinjection in mammalian zygotes on preimplantation development of (CBA x C57BL)F1 mouse embryos in vitro. The rate of embryo survival was estimated according to their capacity to develop to the stages of blastocyst and blastocyst hatched from zona pellucida. The results obtained suggested a reduced rate of survival of zygotes to the blastocyst stage after the injection into a pronucleus of the buffers Tris-HCl with EDTA, Tris-HCl with MgCl2 and NaCl, and medium M2 (p < 0.05) and to the stage of blastocyst hatched from zone pellucida after injection of a Dulbecco solution, as compared to the control. No differences were found in the survival rate of zygotes injected with different buffer solutions.