scholarly journals A new electrochemical method for the determination of chondroitin sulfate based on its supramolecular interaction with cupferron-lead(II) complex

2014 ◽  
Vol 79 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Xueliang Niu ◽  
Pingping Zhang ◽  
Weili Zhang ◽  
Wei Sun
Keyword(s):  
Chondroitin Sulfate ◽  
Interaction Mechanism ◽  
Stable Complex ◽  
Buffer Solution ◽  
Reaction Conditions ◽  
Binding Reaction ◽  
Peak Current ◽  
Other Substances ◽  
Quantitative Determination Method

In this paper, the interaction of cupferron (Cup) and lead (II) complex [Cup-Pb (II)] with chondroitin sulfate (CS) was investigated by linear sweep voltammetric method. In the selected medium of pH 5.5 (acetic acid-hexamine buffer solution), Cup can interact with Pb (II) to form a stable complex of [Cup-Pb(II)], which has a sensitive second order derivative polarographic reductive peak at -0.64V (vs.SCE). After the addition of CS into Cup-Pb (II) complex solution, the reductive peak current decreased without any shift of the peak potential and no new peak appeared, which indicated that an unelectroactive supramolecular complex of CS with [Cup-Pb(II)] was formed. The binding reaction conditions were carefully investigated. Under the optimal conditions, the interaction mechanism was discussed. The decrease of reductive peak current was directly proportional to the CS concentration, thus a new quantitative determination method for CS was established with the linear regression equation as ?Ip?(nA)=36.97 C/mg L-1+12.45 (n=10, ?=0.995). The effects of other substances on the determination were carefully investigated and three synthetic samples were determined with satisfactory results. The binding constant (?s) and the binding number (m) of CS with [Cup-Pb(II)] complex were calculated from the voltammetric data with the results as ?s=1.89?1010 and m?2.5.

A simple linear sweep voltammetric method for the determination of double-stranded DNA with malachite green

2006 ◽  
Vol 60 (3) ◽  
Author(s):  
W. Sun ◽  
J. You ◽  
X. Hu ◽  
K. Jiao
Keyword(s):  
Malachite Green ◽  
Interaction Mechanism ◽  
High Sensitivity ◽  
Electrochemical Determination ◽  
Supramolecular Complex ◽  
Linear Sweep ◽  
Buffer Solution ◽  
Peak Current ◽  
Double Stranded Dna

AbstractIn pH 3.5 Britton—Robinson buffer solution double-stranded (ds) DNA can react with malachite green (MG) to form an interaction complex, which resulted in the decrease of the electrochemical response of MG, MG had a well-defined second-order derivative linear sweep voltammetric peak at −0.73 V (vs. SCE). After the addition of dsDNA into MG solution, the reductive peak current decreased with the positive shift of peak potential, which was the typical characteristic of intercalation. Based on the interaction, an indirect electrochemical determination method for dsDNA was established. The optimum conditions for the reaction were investigated and there were little or no interferences from the commonly coexisting substances. The decrease of peak current was linear with the concentration of dsDNA over the range of 0.8–12.0 µg cm−3 with the linear regression equation as ΔI p″/nA = 91.70 C/(µg cm−3) + 74.55 (n = 10, γ = 0.990). The detection limit was calculated as 0.46 µg cm−3 (3σ). The method had high sensitivity and was further applied to the dsDNA synthetic samples with satisfactory result. The interaction mechanism was discussed with the intercalation of DNA-MG to form a supramolecular complex and the stoichiometry of the supramolecular complex was calculated by electrochemical method with the binding number 3 and the binding constant 2.35 × 1015 (mol dm−3)−3.

scholarly journals Sensitive voltammetric detection of yeast RNA based on its interaction with Victoria Blue B

2009 ◽  
Vol 74 (12) ◽  
pp. 1467-1476 ◽  
Author(s):  
Weili Zhang ◽  
Xueliang Niu ◽  
Na Zhao ◽  
Wei Sun
Keyword(s):  
Interaction Mechanism ◽  
Linear Sweep Voltammetry ◽  
Reduction Peak ◽  
Linear Sweep ◽  
Buffer Solution ◽  
Peak Current ◽  
Voltammetric Detection ◽  
Voltammetric Studies ◽  
Rna Complex

Voltammetric studies of the interaction of yeast RNA (y-RNA) with Victoria Blue B (VBB) are described in this paper. Furthermore, a linear sweep voltammetric method for the detection of y-RNA was established. The reaction conditions, such as acidity and amount of buffer solution, the concentration of VBB, the reaction time and temperature, etc., were carefully investigated by second order derivative linear sweep voltammetry. Under the optimal conditions, the reduction peak current of VBB at -0.75V decreased greatly after the addition of y-RNA to the solution without any shift of the reduction peak potential. Based on the decrease of the peak current, a new quantitative method for the determination of y-RNA was developed. The effects of co-existing substances on the determination were carefully investigated and three synthetic samples were determined with satisfactory results. The stoichiometry of the VBB-y-RNA complex was calculated by linear sweep voltammetry and the interaction mechanism is discussed.

scholarly journals A Simple and Sensitive Inhibitory Kinetic Method for the Carbocisteine Determination

2021 ◽  
Vol 66 (1) ◽  
Author(s):  
Abhishek Srivastava ◽  
Vivek Sharma ◽  
Vinay Kumar Singh ◽  
Krishna Srivastava
Keyword(s):  
Good Accuracy ◽  
Quantitative Estimation ◽  
Kinetic Method ◽  
Fixed Time ◽  
Disodium Salt ◽  
Disulfonic Acid ◽  
Stable Complex ◽  
Reaction Conditions ◽  
Kinetic Determination

Abstract. A fast, reproducible, and sensitive method is proposed for the kinetic determination of carbocisteine (CCys). The method depends on the inhibitory property of carbocisteine, which reduces the Hg2+ catalyzed substitution rate of cyanide from [Ru(CN)6]4- with N-R-salt (1-Nitroso-2-naphthol-3,6-disulfonic acid disodium salt) via forming a stable complex with Hg2+. Spectrophotometric measurements were carried out by recording the absorbance at 525 nm (λmax of [Ru(CN)5 Nitroso-R-Salt]3- complex) at a fixed time of 10 and 15 min under the optimized reaction conditions with [N-R-salt] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M and [Ru(CN)64-] = 4.25 × 10-5  M. With the proposed method, CCys can be determined quantitatively down to 3.0 × 10-6 M. This methodology can be effectively used for the rapid quantitative estimation of CCys in the pharmaceutical samples with good accuracy and reproducibility. The addition of common excipients in pharmaceuticals even up to 1000 times with [CCys] does not interfere significantly in the estimation of CCys.   Resumen. Se propone un método rápido, reproducibley sensible para la determinación cinética de la carbocisteina (CCys). El método depende de la propiedad inhibitoria de la carbocisteina que reduce la tasa de sustitución catalizada por Hg2+ del cianuro de [Ru(CN)6]4- con la sal N-R (sal disódica del ácido 1-Nitroso-2-naftol-3,6-disulfónico) mediante la formación de un complejo estable con Hg2+. Las mediciones espectrofotométricas se llevaron a cabo registrando la absorbancia a 525 nm (λmax del complejo [Ru(CN)5 Sal-Nitroso-R]3-) en un tiempo fijo de 10 y 15 min en las condiciones de reacción optimizadas con [sal-NR] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M y [Ru(CN)64-] = 4.25 × 10-5 M. Con el método propuesto, CCys se puede determinar cuantitativamente hasta 3,0 × 10-6 M. Esta metodología se puede utilizar eficazmente para la estimación cuantitativa rápida de CCys en las muestras farmacéuticas con buena precisión y reproducibilidad. La adición de excipientes comunes en productos farmacéuticos incluso hasta 1000 veces con [CCys] no interfiere significativamente en la estimación de CCys.

Some remarks concerning polarographic determination of sulphur-containing herbicides

1984 ◽  
Vol 49 (5) ◽  
pp. 1282-1288 ◽  
Author(s):  
Věra Stará ◽  
Miloslav Kopanica
Keyword(s):  
Differential Pulse Voltammetry ◽  
Concentration Dependence ◽  
Acidic Medium ◽  
Differential Pulse ◽  
Hanging Mercury Drop Electrode ◽  
Voltammetric Curve ◽  
Buffer Solution ◽  
Peak Current ◽  
Pulse Voltammetry

The herbicide methomyl (2-methylthio-propionaldehyde-o-methylcarbamoyloxime) can be determined using fast scan differential pulse voltammetry with hanging mercury drop electrode by the measurement of the peak at -1.30 V (S.C.E.) which caused by the presence of methomyl in the ammoniacal buffer solution containing cobalt(II) salt. The peak current vs methomyl concentration dependence is linear over the concentration range 0.5 to 20.0 μg . l-1. The herbicide aldicarb (2-methyl-2(methylthio)propionaldehyde-o-methylcarbamoyloxime) is determined by its influence on the differential pulse voltammetric curve of copper(II) recorded in electrochemically enriched solution in acidic medium. The corresponding peak current at the potential + 0.08 V (S.C.E.) depends linearly on the aldicarb concentration in the range 0.07 to 5.00 μg ml-1.

scholarly journals Exploratory study on sequestration of some essential metals by indigo carmine food dye

2010 ◽  
Vol 46 (4) ◽  
pp. 723-730 ◽  
Author(s):  
Thalita Boldrin Zanoni ◽  
Arnaldo Alves Cardoso ◽  
Maria Valnice Boldrin Zanoni ◽  
Antonio Aparecido Pupim Ferreira
Keyword(s):  
Indigo Carmine ◽  
Stable Complex ◽  
Stoichiometric Ratio ◽  
Buffer Solution ◽  
Carbonate Buffer ◽  
Food Dye ◽  
Pre Treatment ◽  
The Stability ◽  
Determination Of Copper

Indigo carmine forms a stable complex with different ions, and the stability constant of the complexes were evaluated as log K equal to 5.75; 5.00; 4.89 and 3.89 for complexes with Cu(II), Ni(II), Co(II) and Zn(II) ions, respectively, in 0.1 mol L-1 carbonate buffer solution at pH 10. The interaction between Cu(II) ions and indigo carmine (IC) in alkaline medium resulted in the formation of the Cu2(IC) complex, measured by the spectrophotometric method, with a stoichiometric ratio between indigo carmine and metal ions of 2:1 (metal-ligand). The reported method has also been successfully tested for determination of copper in pharmaceutical compounds based on copper-gluconate without pre-treatment.

scholarly journals Voltammetric albumin quantification based on its interaction with carminic acid

2006 ◽  
Vol 71 (4) ◽  
pp. 385-396 ◽  
Author(s):  
Wei Sun ◽  
Yunying Han ◽  
Kui Jiao
Keyword(s):  
Serum Albumin ◽  
Human Serum ◽  
Mercury Electrode ◽  
Carminic Acid ◽  
Optimal Conditions ◽  
Binding Reaction ◽  
Peak Current ◽  
Dropping Mercury Electrode ◽  
Voltammetric Detection

In a weak acidic Britton-Robinson (B-R) buffer of pH 4.0, human serum albumin (HSA) can react rapidly with carminic acid (CAA) to form a supramolecular complex. Microelectrostatic fields in the molecular structure of HSA cause the electrostatic binding reaction of the positively charged CAA with the negatively charged HSA. CAA has a sensitive, second order derivative linear sweep voltammetric reductive peak at - 0.54 V (vs. SCE) on a dropping mercury electrode (DME). After the addition of HSA to a CAA solution, the reductive peak current of CAA decreased without a shift of the peak potential. Based on the decrease of the peak current, a sensitive voltammetric method for the determination of microamounts of the protein is proposed. The conditions for the binding reaction and the voltammetric detection were optimized. Under the optimal conditions, the decrease of the voltammetric detection were optimized. Under the optimal conditions, the decrease of the voltammetric peak current was in proportion to the quantity of HSA in the range of 2.0 to 70.0 mg l-1, with a linear regression equation ?Ip"(nA)=11.74 C (mg l-1)-12.33 and a detection limit of 2.0 mg l-1 (3?). The method was further applied to the detection of different kinds of proteins, such as bovine serum albumin (BSA), oval albunim (OVA), lipase, etc. The established method was further applied to the determination of the albumin content in human serum samples and the results obtained by this method were in good agreement with the traditional Coomassie Brilliant Blue G-250 (CBB G-250) spectrophotometric method. The binding mechanism is discussed and the binding ratio was calculated from the voltammetric data.

scholarly journals Voltammetric investigation on interaction of Hyaluronic Acid with crystal violet and its analytical application

2013 ◽  
Vol 9 (2) ◽  
pp. 1900-1910
Author(s):  
WeiLi Zhang ◽  
XueLiang Niu ◽  
Ping Ping Zhang ◽  
Wei Sun
Keyword(s):  
Hyaluronic Acid ◽  
Crystal Violet ◽  
Linear Sweep Voltammetry ◽  
Electrochemical Determination ◽  
Linear Sweep ◽  
Buffer Solution ◽  
Reaction Conditions ◽  
Peak Current ◽  
The Difference ◽  
Optimized Conditions

In this paper, the interaction of hyaluronic acid (HA) with crystal violet (CV) was investigated carefully by linear sweep voltammetry on the dropping mercury working electrode (DME). In pH 5.0 Britton-Robinson (B-R) buffer solution, CV has a sensitive, well-defined second order derivative linear sweep voltammetric reductive wave at –0.85 V (vs. SCE). After adding a certain amount of HA into CV solution, the reductive peak current decreased without any shift of reductive peak potential. Based on the difference in the reductive peak current, a new voltammetric method for the detection of HA was established. The reaction conditions and the electrochemical determination were studied and optimized. Under the optimized conditions, the decrease of peak current showed a good linear relationship with the HA concentration in the range from 10.0 to 40.0 mg/L. The linear regression equation was got as ∆ip″(nA)= 84.07 C–527.86  (mg/L) (n=8, γ=0.997) and the detection limit was calculated as 2.65 mg/L (3σ). This new established method was further used to HA determination in the synthetic samples with satisfactory results and good recovery. The stoichiometry of CV-HA complex was calculated and the binding mechanism was also discussed by the electrochemical data.

scholarly journals Polarographic determination of DNA based on its interaction with the phenanthroline-zinc(II) complex

2015 ◽  
Vol 80 (1) ◽  
pp. 87-96
Author(s):  
Ni Hui ◽  
Aiqin Liang ◽  
Changhui Xue ◽  
Wei Sun
Keyword(s):  
Reduction Peak ◽  
Determination Limit ◽  
Peak Potential ◽  
Buffer Solution ◽  
Peak Current ◽  
Reduction Peak Current ◽  
Relative Standard ◽  
Reduction Peak Potential ◽  
Voltammetric Technique

By using the linear sweep voltammetric technique, a phenanthroline (Phen) and zinc(II) (Phen-Zn(II)) complex was used as the electrochemical probe for the determination of double-stranded (ds) DNA. In pH 9.0 Britton- -Robinson (B-R) buffer solution, Phen can interact with Zn(II) to form a stable electroactive [Phen-Zn(II)] complex, which had a sensitive second order derivative polarographic reductive peak at -1.300 V (vs. SCE). After the addition of dsDNA into a solution of Phen-Zn(II) complex, the reduction peak current decreased with a negative shift of the reduction peak potential and without the appearance of new peaks. The results showed that a new supramolecular complex was formed via interaction of the Phen-Zn(II) complex with dsDNA. The conditions of interaction and the electrochemical detection were carefully investigated. Under the optimum conditions, the decrease in the reduction peak current was directly proportional to the dsDNA concentration in the range of 0.4-18.0 mg L-1 with the linear regression equation: ?Ip?/nA = 349.48 + + 84.647(c/mg L-1) (n = 13, ? = 0.991) and a determination limit of 0.20 mg L-1 (3?). The relative standard deviation (RSD) for 10 parallel determinations of 10.0 mg L-1 dsDNA was found to be 2.03 %. The method was successfully applied to the detection of synthetic samples with satisfactory results.

Determination of Radiochemical Purity and Pharmacokinetic Parameters of 99mTc-Sulphur Colloid and 99mTc-Tin Colloid

1981 ◽  
Vol 20 (06) ◽  
pp. 279-282 ◽  
Author(s):  
D. Konstantinovska ◽  
K. Milivojević ◽  
J. Bzenić ◽  
V. Jovanović
Keyword(s):  
Radiochemical Purity ◽  
Slow Component ◽  
Pharmacokinetic Parameters ◽  
Optimum Size ◽  
Buffer Solution ◽  
Chromatography Method ◽  
Fast Phase ◽  
Biodistribution Studies ◽  
Biological Half Time

Labelling yield and radiochemical purity, higher than 95%, of 99mTc-colloid preparations were determined by using the paper chromatography method. Less than 3% of labelled citric acid, added to the preparation as a buffer solution, has been found in 99mTc-sulphur colloid. High radiochemical purity and optimum size of colloid particles has also been proved by biodistribution studies on experimental animals. The analysis performed has shown that more than 50% of 99mTc-colloid preparations excreted by urine is 99mTcO–, the remaining past 50% being protein bound 99mTc. Biological half-time of excretion of the fast phase is the same for both preparations, i.e. 10 min, while for the slow component it is 120 min in 99mTc-S-colloid and 160 min in 99mTc-Sn colloid.

Indirect Determination of Amikacin by Gold Nanoparticles as Redox Probe

2020 ◽  
Vol 17 ◽  
Author(s):  
Mansureh Alizadeh ◽  
Mandana Amiri ◽  
Abolfazl Bezaatpour
Keyword(s):  
Gold Nanoparticles ◽  
Bacterial Infections ◽  
Limit Of Detection ◽  
Pharmaceutical Preparation ◽  
Cathodic Peak ◽  
Easy Method ◽  
Peak Current ◽  
Indirect Determination ◽  
Tract Infections

: Amikacin is an aminoglycoside antibiotic used for many gram-negative bacterial infections like infections in the urinary tract, infections in brain, lungs and abdomen. Electrochemical determination of amikacin is a challenge in electroanalysis because it shows no voltammetric peak at the surface of bare electrodes. In this approach, a very simple and easy method for indirect voltammetric determination of amikacin presented in real samples. Gold nanoparticles were electrodeposited at the surface of glassy carbon electrode in constant potential. The effect of several parameters such as time and potential of deposition, pH and scan rates on signal were studied. The cathodic peak current of Au3+ decreased with increasing amikacin concentration. Quantitative analysis of amikacin was performed using differential pulse voltammetry by following cathodic peak current of gold ions. Two dynamic linear ranges of 1.0 × 10−8–1.0 × 10-7 M and 5.0 × 10−7–1.0 × 10-3 M were obtained and limit of detection was estimated 3.0× 10−9 M. The method was successfully determined amikacin in pharmaceutical preparation and human serum. The effect of several interference in determination of amikacin was also studied.

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