Conductometric Determination Research Articles

Reproducibility of the Results of the Conductometric Determination of the Degree of Dilution of the Essentuki-4 Mineral Water

Reproducibility of the Results of the Conductometric Determination of the Degree of Dilution of the Essentuki-4 Mineral Water

Reproducibility of the Results of the Conductometric Determination of the Degree of Dilution of the Essentuki-4 Mineral Water

Reproducibility of the Results of the Conductometric Determination of the Degree of Dilution of the Essentuki-4 Mineral Water

Conductometric Determination of Ammonium in Turbid Water with a Flow-batch Porous Membrane-based Diff usion Scrubber System

A porous membrane-based diffusion scrubber was fabricated to couple with a conductometric detector as a fl ow-batch system for determining ammonium in turbid surface waters. A gravity fl ow of DI water as a gas absorbing liquid and a manual sample introduction was employed to develop a cost- effective device without using a conventional pump and an injection valve. The standard calibration graph was linear in the range of 5 – 100 μmol L-1, with a relative standard deviation of < 5%. The detection limit based on the lowest concentration in the calibration graph of 5 μmol L-1 can be obtained. The results of ammonium determination using the proposed method agree well with those using the batch-wise indophenol blue as a standard method. The proposed analytical system provides a cost-effective setup and easy operation for ammonium determination in some turbid surface waters samples without requiring a fi ltering process and conventional glassware.

Sampling, sample handling and sample preparation of raw sugar, white sugar, speciality sugars and plantation white sugar

Good sampling methods can reduce the sampling error, bad increase it; the contribution of sampling error to what is perceived to be analytical error is as important as any error in the analyses themselves. The ICUMSA® Referee for Sampling, sample Handling and sample Preparation has carried out a three stage study to establish new sampling guidelines for crystalline and liquid sugars. The paper is a shortened version of his report for the ICUMSA® Proceedings 2021 detailing the experimental layout aiming to obtain an optimized way of preparing test samples from laboratory samples. The analytical results of the conductometric ash determination with their statistical analysis are given and compared with previous studies. Based on the results the 2022 ICUMSA® Methods book includes new standards on the collection of laboratory samples, highlighting known pitfalls and suggesting ways that they may be avoided.

“Green” method for monitoring the mineral composition of spring waters based on the results of double measurement of specific electrical conductivity

The “green” method of conductometric determination of the double dilution coefficients has been tested according to the results of monthly measurements during the year of the specific electrical conductivity of undiluted and twice diluted underground water from 4 springs. The first coefficient characterizes the ratio of mono- and divalent cations and anions in the water under study, the second one characterizes the content of dissolved salts in mg-eq/dm3, which makes it possible to establish the hydrochemical type of the water under study. The technique can be classified as environmentally friendly since natural diluted distilled water serves as waste.

Conductometric determination of trospium chloride by silver nitrate and phosphomolybidic acid

Two simple, accurate, sensitive and precise conductometric methods were developed for determination of trospium chloride in pure form and in pharmaceutical formulations. It is based on using two precipitating reagents; Phosphomolybdic acid (PMA) and Silver nitrate (AgNO3). The mean recovery for Silver nitrate is in the range (98-100.95%) and for Phosphomolybdic acid in the range (98-101.69%). A molar ratio has been determined conductometrically for the two reagents, revealed (1/1) for (drug/reagent). The proposed methods were validated and successfully applied for the determination of the studied drug in pure form and in its pharmaceutical preparation. The results of the proposed methods were compared to the results of reported method with no significant difference between them.

Conductometric determination of Betahistine dihydrochloride and Heptaminol hydrochloride using silver nitrate

A simple, precise and cost effective conductometric method was developed for determination of betahistine dihydrochloride and heptaminol hydrochloride in pure form and pharmaceutical formulations. The method is based on the precipitation of chloride ions present in cited drugs with silver ions, yielding silver chloride, the conductance of the solution is measured as a function of the volume of titrant. Effect of solvent, reagent concentration, temperature were studied and evaluated. The suggested method was applied for determination of betahistine dihydrochloride and heptaminol hydrochloride in pure forms and pharmaceutical preparations. The described procedure allowed the determination of betahistine dihydrochloride and heptaminol hydrochloride in the range of 2-10mg/ml and 2-13mg /ml respectively.The molar ratio was (2:1),(1:1) (drug:reagent) between betahistine dihydrochloride and heptaminol hydrochloride with silver nitrate respectively. The suggested procedure was applied successfully to the analysis of these drugs in their pharmaceutical formulations, and the results obtained were in agreement with those given by the official methods

Static and dynamic approach to estimation of spring water mineralization stability as a factor of groundwater ecological safety

To assess the degree of influence of technogenic factors on the groundwater mineralization, it is proposed to consider simultaneously in a static and dynamic position the results of conductometric determination in spring water of generalized indicators, such as electrical conductivity and the coefficient of identification of the mineral composition of water. This is shown by the example of four springs located in the territory of Kaluga. This made it possible to establish the average annual background values of electrical conductivity and the coefficient of identification of the mineral composition of water, as well as to justify the permissible or weakly expressed degree of influence of technogenic factors on the quality of groundwater in the period from November 2017 to October 2018 by the criterion of exceeding the error of the conductometric method (2%) by 3 or more times.

MgNi2O3 nanoparticles as novel and versatile sensing material for non-enzymatic electrochemical sensing of glucose and conductometric determination of acetone

In the present work, we report the synthesis of pure MgNi2O3 and MgNi2-xAxO3 (A = Co or Zn; x = 2.5, 10, 25 wt%) nanoparticles by chemical precipitation method and its novel applications in the field of chemical sensors. Powder XRD, SEM, HRTEM and XPS characterization of the synthesized samples indicate formation of nearly phase pure undoped MgNi2O3 nanoparticles. At lower concentration (2.5 and 5 wt%), both Co and Zn loading yielded nearly phase pure Mg-123 samples. On the other hand, increase in dopant concentration, led to the segregation of small quantity of impurity phases Co3O4 and ZnO with the major phase being Mg-123. Results of electrical and electrochemical characterization studies indicated the influence of the dopants on the physical and chemical properties of MgNi2O3. Both the pure and doped MgNi2O3 nanoparticles have been applied for the fabrication of electrochemical and conductometric sensors for monitoring blood glucose and breath acetone respectively. Electrochemical tests indicated that the Co–MgNi2O3 is highly effective for the electrochemical detection of glucose. Under optimal conditions, glucose was monitored at concentration from 0.05 mM to 5 mM with sensitivity of 528.6 μA mM−1cm−2. With regard to breath acetone detection, the Zn–MgNi2O3 conductometric sensor showed the best performances with high response and low detection limit (0.5 ppm at SN = 3), fast response/recovery times of about 25 s and 250 s, respectively, at the operating temperature of 200 °C. The good electrochemical and gas sensing performances suggest that MgNi2O3 based nanomaterials can be considered as versatile and promising candidates for developing chemical sensors helpful in the management of acute complications of insulin dependent diabetes, such as hypoglycemia and ketoacidosis.

Determinação Condutométrica de Cloridratos em Comprimidos como Proposta de Atividade Experimental

Determinação Condutométrica de Cloridratos em Comprimidos como Proposta de Atividade Experimental

Extraction conductometric determination of scandium and thorium in kaolins

Extraction conductometric determination of scandium and thorium in kaolins

Conductometric Titration for Determination of Trazodone Hydrochloride and Solubility Products of its Ion-Associated Complex Species

Objective: Conductometric determination of trazodone hydrochloride, with two precipitating reagents; Ammonium Reineckate and sodium tetraphenylborate has been investigated.Methods: The formed ion-associates were studied conductomterically for the determination of solubility products and other functions associated with the process of precipitating trazodone hydrochloride were determined. Moreover, two new maneuvers towards equivalence point detection were carried out. In this study, data processing was performed using numerical derivatization (second derivative) and Boltzmann algorithm. Results: Although, the described procedures allowed the determination of trazodone hydrochloride within the range of 2-14 mg using both reagents has less sensitivity other than reported method but has more advantages in simplicity, low cost , relatively short analysis time and direct analysis with good recoveries between 100.01% and 100.07% with relative standard deviation less than 2%. Conclusion: These methods were validated and successfully applied for the determination of trazodone hydrochloride in Trittico® tablets. The obtained results were statistically compared with those of the official method by applying t-test and F-value at 95% confidence level and no significant difference was observed regarding accuracy and precision.

New Conductometric Titration Methods for Determination of Diphenhydramine Hydrochloride Using Sodium Tetraphenylborate and Cetylpyridinium Bromide

Sodium tetraphenylborate (TPB) and cetylpyridinium bromide (CPB) were used as titrant for the conductometric determination of diphenhydramine hydrochloride (DPH) drug through ion association complex formation and then the conductance of the solution is measured as a function of the volume of titrant. The effect of the solvent, reagent concentration, temperature and molar combining ratio of the formed ion-associates were studied and evaluated. The suggested method was applied for the determination of diphenhydramine hydrochloride in pure form and pharmaceutical preparations. The described procedures allowed the determination of the studied drug in bi-distilled water in the range of 0.75–16 mg. Statistical treatment of the experimental results indicates that the method is precise and accurate. The accuracy of the method was indicated by excellent recovery and the precision supported by the low relative standard deviation <1%. The sensitivity of the proposed method was discussed and the results were compared with the potentiometric pharmacopoeial method. The proposed procedure was simple, precise and low cost and can be applied for the routine measurements of the cited drug.

Relationships between leaf morpho‐anatomy, water status and cell membrane stability in leaves of wheat seedlings subjected to severe soil drought

AbstractThe impact of the genotype‐specific leaf morphological and anatomical characteristics on the ability of wheat plants to preserve leaf water balance and cell membranes stability under drought stress was investigated. Seedlings of six modern semi‐dwarf (carriers of Rht, Reduced height genes) and six old tall bread wheat varieties were subjected to soil drought by withholding watering for 6 days. Morpho‐anatomical traits (leaf area, perimeter, thickness, stomata and trichome density) of daily watered (control) plants were characterized by light microscopy, scanning and image analyses. The leaf water status in both control and stressed plants was determined by measuring the relative water content (RWC). The leaf cell membranes stability in stressed plants was estimated by conductometric determination of the membranes injury index. On average, the modern semi‐dwarf varieties had less leaf area and leaf perimeter, and less dissection index, a parameter characterizing the leaf shape. Under drought stress, the modern genotypes maintained better water balance evidenced by significantly higher leaf RWC and better‐preserved the cell membranes stability supported by significantly lower Injury index. The correlations between morpho‐anatomical traits in control plants and drought tolerance‐related traits showed that the higher the leaf dissection index (i.e. more oblong leaves), the greater the water loss and the leaf membrane damages after desiccation were. The effect of shape of the evaporating surface on the water loss was modelled using wet filter paper. Similar to plant leaves, the evaporation and, respectively, water loss from paper pieces of more oblong shape (i.e. higher dissection index) was more intensive. The elucidation of the impact of the leaf shape on transpiration might contribute to better understanding of the mechanisms used by plants to maintain water reserves during drought stress and could be a basis for developing of simple and fast screening methods aiding the selection of drought tolerant genotypes.

Effect of oil droplet size on the oxidative stability of spray-dried flaxseed oil powders

The effect of the size of oil droplets on the oxidative stability of flaxseed oil in spray-dried powders was investigated. Maltodextrin with a dextrose equivalent of 25 was used as a wall material, and sodium caseinate and transglutaminase-polymerized sodium caseinate were used as emulsifiers. The oxidative stability of flaxseed oil encapsulated in the spray-dried powders was evaluated using lipid oxidation and conductometric determination tests at 105°C. The powders containing larger oil droplets exhibited higher surface oil content after spray drying, and higher peroxide value and conductivity after storage at 105°C. Removal of the surface oil from the powders by washing with hexane significantly decreased the conductivity. The results indicated that the surface oil of the spray-dried flaxseed oil powders affected the oxidation stability.

Effects of Triacylglycerol Molecular Species on the Oxidation Behavior of Oils Containing α-Linolenic Acid.

Two kinds of oils, pure perilla oil and a blend of perilla oil with palm oil, and their enzymatically interesterified oils having the same fatty acid compositions but with different compositions of triacylglycerol (TAG) species, were studied. In particular, the effects of TAG molecular species on the oxidation resistance of oils containing α-linolenic acid (Ln) were investigated. The content of TAG binding to three Ln molecules (3Ln-TAG) was found to be different between perilla oil (38.7%) and the interesterified oils (14.5-28.9%) , which were generated using Lipozyme RM-IM(®) (regiospecificity: sn-1, 3 positional). Oils with lower 3Ln-TAG contents were more stable to oxidation as determined by the conductometric determination method (CDM; 90°C, 20 L/h) than oils with higher 3Ln-TAG contents. This result was also supported by heating oxidation tests (180°C, 7 h) using the interesterified blended oils; the residual ratio of Ln-TAGs in the oils was found to be in the order of 3Ln-TAG<2Ln-TAG<1Ln-TAG. Oxidation stability of Lipase OF(®) (regiospecificity: random)-interesterified blended oils also improved on lowering the 3Ln-TAG content. In addition, the oxidation stabilities of Lipozyme RM-IM(®)-interesterified oils were slightly higher than those of the Lipase OF(®)-interesterified oils. We found that the content of 3Ln-TAG was almost the same in both oils, and the content of unsaturated fatty acid at the sn-1, 3 positions of Lipase OF(®)-interesterified oils was higher than that of Lipozyme RM-IM(®)-interesterified oils. These results indicate that oxidation stabilities of oils containing TAG with unsaturated fatty acid such as Ln at sn-2 position were higher than those having unsaturated fatty acids at the sn-1, 3 positions. From these results, the oxidation stability of oils rich in Ln, such as perilla oil and linseed oil, can be improved not only by decreasing 3Ln-TAG but also by enzymatically reducing the unsaturated fatty acid content at the sn-1, 3 positions.

Possibility and reliability of conductometric determination of limiting ionic conductivities and complexation constants in solutions of 1-1 electrolytes in non-aqueous solvents with neutral ligands.

Possibility and reliability of conductometric determination of limiting ionic conductivities and complexation constants in solutions of 1-1 electrolytes in non-aqueous solvents with neutral ligands.

Contactless conductometric determination of methanol and ethanol in samples containing water after their electrophoretic desalination.

Determination of the contents of methanol and ethanol in aqueous solutions was performed by measuring the permittivity of solutions using a contactless conductivity detector (C(4) D) normally used for detection in capillary electrophoresis. The detection cell is a section of a fused silica capillary with an internal diameter of 50 μm with a pair of conductivity electrodes on the external walls. The C(4) D response to samples of methanol/water and ethanol/water mixtures is linear in the concentration interval of approx. 40-100% v/v alcohol content. In the analysis of technical samples of methanol and ethanol, the determination is disturbed by the presence of even trace amounts of salts. This interference can be effectively eliminated by integrated electrophoretic desalination of the sample by the application of a direct current electric voltage with a magnitude of 10 kV to the capillary with the injected sample zone. Under these conditions, the ions migrate out of the sample zone and the detector response is controlled purely by the permittivity of the solvent/water zone. Desalinating is effective for NaCl contents in the range from 0 to 5 mmol/L NaCl. The effectiveness of the desalinating process has been verified on MeOH/water samples and in determination of the ethanol content in distilled beverages normally available in the retail network.

Synthesis and evaluation of homopolymer and terpolymer based on phenyl salicylate as photostabilizers for rigid polyvinylchloride

Terpolymer based on polymerizable derivative of phenyl 5-methacryloxy methyl salicylate (PMMS) methyl methacrylate (MMA)/2-hydroxyethyl methacrylate (HEMA)/PMMS was synthesized and evaluated as a photostabilizer for rigid polyvinylchloride (PVC). Evaluation of stabilizing efficiency was carried out by measuring the induction period and the rate of dehydrochlorination by the continuous conductometric determination of the hydrochloric acid (HCl) evolved at 25°C under nitrogen in addition to the extent of discoloration. The results indicated that the stabilizing effect of this terpolymer increased upon increasing the stabilizer concentration and the content of the UV absorber units in the terpolymer. The prepared terpolymer showed higher stabilizing efficiency when compared to the homopolymer of the phenyl salicylate-based monomer and the commercial UV absorber, phenyl salicylate. Structural morphology of PVC/terpolymer blend was investigated using a scanning electron microscopy (SEM) and thermal properties of the blends were also studied using differential scanning calorimetry (DSC). J. VINYL ADDIT. TECHNOL., 23:70–77, 2017. © 2015 Society of Plastics Engineers

Conductometric determination of ammonium ion with a mobile drop

A mobile drop based approach was utilized for the conductometric determination of aqueous ammonium ion. A liquid drop was manipulated by gravity to remain or move out of a conductivity measurement zone located on a hydrophobic path. A dilute sulfuric acid drop functioned as a micro gas absorber. Gaseous NH3 was liberated from a sample containing NH4+ by adding NaOH and purged to flow over the absorber drop. As H+ in the absorber drop was converted to NH4+, the conductivity decreased. The rate of the conductivity decrease thus ultimately depended on the NH4+ concentration in the sample. While the sample could be complex, the liberation of NH3 gas essentially freed the analyte of interest from the matrix and allowed the use of an otherwise nonselective detector. The system was applied to the determination of NH4+ in some natural waters without prior filtration; the results agreed well with those from a manual indophenol blue method. The approach exhibited a limit of detection (LOD) of 5μM and a relative standard deviation (RSD) of<5%. The mobile drop gave a constant volume of the gas absorbing solution and provided a cost-effective and simple analytical platform.