scholarly journals Preparation and Description of Potentiometric Electrode for the Limitation of Sulbutamol Sulphate

2019 ◽  
Author(s):  
Mohauman Majeed ◽  
Zahraa Motaweq
Keyword(s):  
Selectivity Coefficient ◽  
Membrane Electrode ◽  
Relative Standard Error ◽  
Pharmaceutical Drugs ◽  
Counter Anion ◽  
Direct Potentiometry ◽  
Relative Standard ◽  
Electrode Selectivity ◽  
Ph Range ◽  
Complex Ion

A new sulbatamol sulphate SBS membrane electrode was prepared that utilizing for its determination ; depend on the forming of the association complex ion of sulbatamol sulphate by the phosphotungstate counter anion deposed in poly vinyl chloride PVC polymer, by use a (Di-n- Octyl Phenyl Phthalate)(Dopp) as the plastizier substance, in membrane.The features properties as well as the behavior of it .The new electrode have been elaborated. The concentrations of medicine by utillizing This sensor show a fast, stable, near-Nernstian response in the range (1x10-1-1x10-6) mol/ L were determined with correlation coefficient of about (r = 0.9991) and with of a relative standard about 0.416 additionally deviation relative standard error of 1.710  %.pot The nernast linearity slop was founded and it is equal to 28.9 mV/decade and the detection limit was 4.1 x 10-6 mol/ L.The electrode selectivity coefficient Ki,j was calculated, in the existence of several interferences cations with confirmed medicine solutions. It was found the pH range response is in the range of (3 -7), with the response time of (30 – 116) sec. for various  concentrations at room temperture , the lifetime for  electrode was found to be more than 21 days. The electrode was successfully used for potentiometric limitation of sulbatamol sulphate in several pharmaceutical drugs by using direct potentiometry.

scholarly journals Phosphorated Calix[6]arene Derivatives as an Ionophore for Atropine-Selective Membrane Electrodes

2007 ◽  
Vol 90 (1) ◽  
pp. 147-152 ◽  
Author(s):  
Mohsen M Zareh ◽  
Elizabeita Malinowska
Keyword(s):  
Selectivity Coefficient ◽  
Atropine Sulfate ◽  
Eye Drops ◽  
Membrane Electrodes ◽  
Relative Standard ◽  
Optimum Ph ◽  
Selective Membrane ◽  
Ph Range ◽  
Polyvinyl Chloride Membrane ◽  
Optimum Ph Range

Abstract 37,40-bis-(diethoxy-thiophosphoryl)oxy-5,11,17, 23,29,35-hexakis(1,1-dimethyl-ethyl)-calix[6]arene-8,39,41,42-tetrol; 37,38,39,40,41-pentakis-(diethoxythiophosphoryl)-oxy-5,11,17,23,29,35-hexakis (1,1-dimethylethyl)-calix[6]-arene-42-ol; and 37-(diethoxythiophosphoryl)oxy-5,11,17,23,29,35-hexakis-(1,1dimethylethyl)-calix[6]arene-38,39,40, 41,42-pentol were introduced as neutral ionophores for atropine-selective electrodes. Practical Nernstian responses were found (54.3, 49.1, and 50.8 mV/decade) for polyvinyl chloride membrane electrodes incorporating these compounds. They exhibited practical linear ranges of 1.9 10-6-7.9 10-3,7.9 10-6-7.9 10-3, and 6.3 10-6-7.9 10-3 M, respectively. The optimum pH range was 2.58.5. The selectivity coefficient values were estimated and interpreted. The electrode performance was correlated to the calixarene structure. Then, the electrode was applied to an actual analysis of pharmaceutical atropine preparations. The recovery values of 18.7 g/mL-5.5193 mg/mL atropine sulfate were 97.599.1%. The corresponding relative standard deviation values ranged between 0.39-0.72% for 5 determinations. The first electrode was applied successfully for analyzing atropine sulfate in injection solution and eye drops.

Manufacturing of a New Selective Membrane Electrode for Neomycin Sulfate and its Estimation by Potentiometric Method

2021 ◽  
Vol 19 (10) ◽  
pp. 121-126
Author(s):  
Seemma Hamed Ahmed ◽  
Mumin Fareed Hamad Al-Samarrai ◽  
Imad Tarek Hanoon ◽  
Afrah Saad Salih
Keyword(s):  
Selectivity Coefficient ◽  
Effect Of Temperature ◽  
Membrane Electrode ◽  
Factors Affecting ◽  
Selective Membrane ◽  
Neomycin Sulfate ◽  
Butyl Phthalate ◽  
Ph Range ◽  
Interfering Ions ◽  
Positively Charged

The research aims to prepare a new ionic membrane selective electrode for NYM Neomycin based on tungstophosphoric acid (TPA), Poly Vinyl Chloride (PVC) and DPPH (Di-Butyl Phthalate). It was found that the electrode is sensitive to concentrations ranging between (1 x 10-1-1 x 10-5) mol/L, and it gave a Nernstian response of (29.7 mV/decade) and a correlation coefficient (r) of (0.9939). The factors affecting the response of the electrode were studied, as it was found that the best concentration of the internal filling solution was (1 x 10-3) mol/L, and that the best pH range in which the electrode worked was between (3.5-1.5) and the best Nernstian response at pH (pH = 2.5) The effect of temperature was also studied, as it was found that the best temperature was (25°C) and the response time of the electrode was between (20-40) seconds. It was also found that the chronological age of the electrode was (25) days. The selectivity coefficient (Ki,jpot) was calculated in the presence of negative and positively charged interfering ions.

A polyvinylchloride-based cadmium ion-selective electrode using [Mo2(OAc)2(H2-calix[4]arene)] as an electroactive material

2010 ◽  
Vol 62 (11) ◽  
pp. 2510-2518 ◽  
Author(s):  
Sonika Tyagi ◽  
Himanshu Agarwal ◽  
Saiqa Ikram
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Indicator Electrode ◽  
Membrane Electrode ◽  
Electroactive Material ◽  
Direct Potentiometry ◽  
Electrode Sensor ◽  
Sodium Tetraphenyl Borate ◽  
Nernstian Slope ◽  
Tetraphenyl Borate ◽  
Ph Range

A highly electroactive material Mo2[(OAc)2(H2-calix[4]arene)] is used as a neutral carrier for Cd2 +  ions in this paper. The membrane is fabricated by using ionophore [Mo2(OAc)2(H2-calix[4]arene)]:poly(vinyl chloride) (PVC): dibutylphthalate(DBP):sodium tetraphenyl borate (NaTPB) in the ratio of 40:300:470:5 respectively and tetrahydrofuran (THF) used as a solvent. The membrane electrode performed in the concentration range of 9.9 × 10−8–1.0 × 10−1 M (2.34 × 10−5–23.64 mg/mL) having the Nernstian slope of 30.0±1.0 mV and the best detection limit was observed at 9.8 × 10−8 M (2.31 × 10−5 mg/mL). The proposed membrane electrode has the response time of 12 s and a useful working pH range of 1.0–7.0, and used over a period of 10 months and work satisfactorily in the test solution having 30% (v/v) non-aqueous content. Electrode sensor has distinguishable ability for Cd2 +  ion with regard to several alkali, alkaline earth, transition and heavy metal ions. It was used in direct potentiometry as an indicator electrode, in the potentiometric titration of 10−3 M Cd2 +  solution against 10−2 M of ethylenediaminetetraacetic acid (EDTA).

Determination of subnanogram amounts of sulfur dioxide and sulfites by pneumatopotentiometry

1986 ◽  
Vol 51 (10) ◽  
pp. 2077-2082 ◽  
Author(s):  
Jan Langmaier ◽  
František Opekar
Keyword(s):  
Sulfur Dioxide ◽  
Redox Potential ◽  
Sodium Hydroxide ◽  
Porous Membrane ◽  
Membrane Electrode ◽  
Iodine Monochloride ◽  
Membrane Pores ◽  
Relative Standard ◽  
Limit Of Quantitation

Gold porous membrane electrode has been used for the potentiometric determination of small amounts of sulfur dioxide absorbed in the solutions of sodium tetrachloromercurate or sodium hydroxide. Sulfur dioxide is released by the reaction with an acid into a stream of nitrogen and led to the electrode immersed into the solution of iodine monochloride. Part of SO2 penetrates through the membrane pores into the solution where it is oxidized. The electrode redox potential change is a measure of the SO2 concentration in the absorption solution. In the solution of 1 . 10-5 M[ICl2]- in 0.02 M-HClO4 the limit of quantitation was found to be 0.07 ng SO2 . ml-1. The relative standard deviations of 1.4% and 2.5% were found for the determinations of 10 ng and 0.5 ng of SO2, respectively. Higher concentrations of H2S interfere only in the hydroxide solution. About 10 samples can be analyzed per one hour.

Novel palladium(II) selective membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol

2010 ◽  
Vol 75 (5) ◽  
pp. 563-575 ◽  
Author(s):  
Moslem Mohammadi ◽  
Mehdi Khodadadian ◽  
Mohammad K. Rofouei
Keyword(s):  
Limit Of Detection ◽  
Membrane Electrode ◽  
Aqueous Samples ◽  
Selective Determination ◽  
Poly Vinyl Chloride ◽  
Selective Membrane ◽  
Ph Range ◽  
Palladium Content ◽  
Methyl Benzene

A plasticized poly(vinyl chloride) membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol (L) for highly selective determination of palladium(II) (in PdCl42– form) is developed. The electrode showed a good Nernstian response (29.6 ± 0.4 mV per decade) over a wide concentration range (3.1 × 10–7 to 1.0 × 10–2 mol l–1). The limit of detection was 1.5 × 10–7 mol l–1. The electrode has a response time of about 20 s, and it can be used for at least 2 months without observing any considerable deviation from Nernstian response. The proposed electrode could be used in the pH range of 2.5–5.5. The practical utility of the electrode has been demonstrated by its use for the estimation of palladium content in aqueous samples.

scholarly journals Lidar arc scan uncertainty reduction through scanning geometry optimization

2016 ◽  
Vol 9 (4) ◽  
pp. 1653-1669 ◽  
Author(s):  
Hui Wang ◽  
Rebecca J. Barthelmie ◽  
Sara C. Pryor ◽  
Gareth. Brown
Keyword(s):  
Theoretical Model ◽  
Wind Speed ◽  
Wind Energy ◽  
Turbulence Intensity ◽  
Wind Direction ◽  
Energy Production ◽  
Elevation Angle ◽  
Relative Standard Error ◽  
Power Performance ◽  
Relative Standard

Abstract. Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production prediction. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation.

scholarly journals Population Pharmacokinetics of Fluconazole in Young Infants

2008 ◽  
Vol 52 (11) ◽  
pp. 4043-4049 ◽  
Author(s):  
K. C. Wade ◽  
D. Wu ◽  
D. A. Kaufman ◽  
R. M. Ward ◽  
D. K. Benjamin ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Relative Standard Error ◽  
Data Set ◽  
Mixed Effect ◽  
Young Infants ◽  
Relative Standard ◽  
Population Pk ◽  
The Impact

ABSTRACT Fluconazole is being increasingly used to prevent and treat invasive candidiasis in neonates, yet dosing is largely empirical due to the lack of adequate pharmacokinetic (PK) data. We performed a multicenter population PK study of fluconazole in 23- to 40-week-gestation infants less than 120 days of age. We developed a population PK model using nonlinear mixed effect modeling (NONMEM) with the NONMEM algorithm. Covariate effects were predefined and evaluated based on estimation precision and clinical significance. We studied fluconazole PK in 55 infants who at enrollment had a median (range) weight of 1.02 (0.440 to 7.125) kg, a gestational age at birth (BGA) of 26 (23 to 40) weeks, and a postnatal age (PNA) of 2.3 (0.14 to 12.6) weeks. The final data set contained 357 samples; 217/357 (61%) were collected prospectively at prespecified time intervals, and 140/357 (39%) were scavenged from discarded clinical specimens. Fluconazole population PK was best described by a one-compartment model with covariates normalized to median values. The population mean clearance (CL) can be derived for this population by the equation CL (liter/h) equals 0.015 · (weight/1)0.75 · (BGA/26)1.739 · (PNA/2)0.237 · serum creatinine (SCRT)−4.896 (when SCRT is >1.0 mg/dl), and using a volume of distribution (V) (liter) of 1.024 · (weight/1). The relative standard error around the fixed effects point estimates ranged from 3 to 24%. CL doubles between birth and 28 days of age from 0.008 to 0.016 and from 0.010 to 0.022 liter/kg/h for typical 24- and 32-week-gestation infants, respectively. This population PK model of fluconazole discriminated the impact of BGA, PNA, and creatinine on drug CL. Our data suggest that dosing in young infants will require adjustment for BGA and PNA to achieve targeted systemic drug exposures.

Determination of total antioxidant capacity of milk by CUPRAC and ABTS methods with separate characterisation of milk protein fractions

2015 ◽  
Vol 82 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Sema Demirci Çekiç ◽  
Aslı Demir ◽  
Kevser Sözgen Başkan ◽  
Esma Tütem ◽  
Reşat Apak
Keyword(s):  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Milk Protein ◽  
Skim Milk ◽  
Protein Fractions ◽  
Relative Standard Error ◽  
Antioxidant Power ◽  
Antioxidant Capacities ◽  
Relative Standard ◽  
Total Antioxidant

Most milk-applied antioxidant assays in literature are based on the isolation and quantification of individual antioxidative compounds, whereas total antioxidant capacity (TAC) gives a more holistic picture due to cooperative action of antioxidants. Recently, the cupric reducing antioxidant capacity (CUPRAC) method has been modified to measure the antioxidant capacities of thiol-containing proteins, where the classical ammonium acetate buffer – that may otherwise precipitate proteins– was replaced with concentrated urea buffer (able to expose embedded thiol groups of proteins to oxidative attack) adjusted to pH 7.0. Thus, antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid))/persulphate, because only these assays were capable of evaluating protein contribution to the observed TAC value. As milk fat caused turbidity, experiments were carried out with skim milk or defatted milk samples. To determine TAC, modified CUPRAC method was applied to whole milk, separated and redissolved protein fractions, and the remaining liquid phase after necessary operations. Both TAC methods were investigated for their dilution sensitivity and antioxidant power assessment of separate milk fractions such as casein and whey. Proteins like β-lactoglobulin and casein (but not simple thiols) exhibited enhanced CUPRAC reactivity with surfactant (SDS) addition. Addition of milk protein fractions to whole skim milk produced significant ‘negative-biased’ deviations (up to −26% relative standard error) from TAC absorbance additivity in the application of the ABTS method, as opposed to that of the CUPRAC method less affected by chemical deviations from Beer's law thereby producing much smaller deviations from additivity (i.e. the property of additivity is valid when the measured TAC of a mixture is equal to the sum of individual antioxidant capacities of its constituents).

scholarly journals Solid phase selective separation and green preconcentration of Cu, Zn, Pb and Cd in drinking water by using novel functionalized resin

2009 ◽  
Vol 7 (4) ◽  
pp. 945-954 ◽  
Author(s):  
Nagwa Burham ◽  
Sami Azeem ◽  
Mohamed El-Shahat
Keyword(s):  
Drinking Water ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Exchange Capacity ◽  
Coupling Reactions ◽  
Lead And Cadmium ◽  
Sample Flow Rate ◽  
Relative Standard ◽  
Copper Zinc ◽  
Ph Range

AbstractA new solid — phase extraction sorbent was developed based on stepwise anchoring of two ligand molecules for the determination of copper, zinc, lead and cadmium in drinking water by flame AAS. Amberlite XAD-2 functionalized with 4′-(2-hydroxyphenylazo)-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one (HPAPyr) was utilized for preconcentration/separation of these elements. The sorbent was prepared by two successive azo coupling reactions. First, 2-aminophenol was anchored to the amino groups in the resin resulted from nitration followed by reduction. Then, the resulted 2-aminophenol functionalized resin was further diazotized and coupled to the pyrazolone compound and the final product HPAPyr-XAD-2 was characterized by IR and elemental analysis. The optimum pH range for sorption, shaking time, exchange capacity, sample flow rate, preconcentration factor and interference from co-existing ions were investigated. All metal ions were quantitatively desorbed from the resin by 4.5 mol L−1 nitric acid solution. The sorbent provides limit of detection within the range 0.9–3.3 µg L−1 and concentration factor up to 250. The procedure was validated by analysis of certified material NIST-SRM 1577b. Application to drinking water showed satisfactory results with relative standard deviation RSD ≤ 8.5%.

Peroxidase Mimic Activities of Copper Selenide (CuSe) Nanoplates for Sensing H2O2 and L-Cysteine

2020 ◽  
Vol 20 (9) ◽  
pp. 5369-5375
Author(s):  
Bai Maojuan ◽  
Xu Chengcheng ◽  
Huang Xuanye ◽  
Liu Yanan ◽  
Wan Jun
Keyword(s):  
Electron Microscopy ◽  
Detection Limit ◽  
Energy Dispersive Spectrometer ◽  
Catalytic Efficiency ◽  
Relative Standard Error ◽  
Colorimetric Determination ◽  
Peroxidase Mimic ◽  
Biomedical Analysis ◽  
X Ray ◽  
Relative Standard

Compared with natural enzymes, artificial mimic enzymes have been widely studied for their high stability and cost effectiveness. In this study, CuSe nanoplates as a simulated enzyme which does not contain precious metals, has peroxidase activity. CuSe nanoplates were prepared and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectrometer (EDS). Kinetic studies show that CuSe nanoplates exhibits a higher affinity for 3,3′,5,5′-teramethylbenzidine (TMB) than horseradish peroxidase (HRP). The rapid colorimetric determination of H2O2 and L-cysteine were developed based on the catalytic efficiency. The linear range of detection for H2O2 is 5.0×10−6~8.0×10−5 M, and the detection limit is 2.9×10−6 M, while the relative standard error is less than 5%. In addition, L-cysteine was detected with a detection limit of 0.2×10−6 M. The good selectivity of the determination to H2O2 and L-cysteine in aqueous solution was also achieved. CuSe nanoplates as a simulated enzyme for sensor applications would be used in environmental monitoring and biomedical analysis.

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