Thioglycolic acid capped CdS quantum dots as a fluorescent probe for the nanomolar determination of dopamine

2015 ◽  
Vol 7 (16) ◽  
pp. 6791-6798 ◽  
Author(s):  
Anuja Elevathoor Vikraman ◽  
Ammu Rosin Jose ◽  
Meera Jacob ◽  
Krishnapillai Girish Kumar
Keyword(s):  
Quantum Dots ◽  
Fluorescent Probe ◽  
Thioglycolic Acid ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Cds Quantum Dots ◽  
Buffer Solution ◽  
Solution Ph ◽  
Selective Determination

Thioglycolic acid (TGA) capped CdS quantum dots (QDs) have been successfully employed as an efficient nano sized fluorescent probe for the selective determination of dopamine (DA) in acetate buffer solution (pH 7).

Capillary isotachophoresis of piperidinoethylethers of the alkoxyphenylcarbamic acids

1986 ◽  
Vol 51 (5) ◽  
pp. 993-1000 ◽  
Author(s):  
Zdeněk Chmela ◽  
Jozef Čižmárik ◽  
Zdeněk Stránský
Keyword(s):  
Acid Medium ◽  
Steric Hindrance ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Capillary Isotachophoresis ◽  
Buffer Solution ◽  
Solution Ph ◽  
Successful Separation

Conditions for the separation and determination of N-[2-(alkoxyphenylcarbamoyloxy)-ethyl]-piperidinium chlorides ( analogues of heptacaine) by the capillary isotachophoresis have been studied. For the successful separation of lower alkoxy derivatives the acetate buffer solution, pHL = 4.75, was found to be a suitable leading electrolyte (K+ as the leading ion) and β-alanine a suitable terminator. The separation can be achieved even in the acid medium with H+ as the leading ion and with a voluminous terminating cation. For instance, pseudoaconitine or N-[2-(2-heptyloxyphenylcarbamoyloxy)-ethyl]-benzylpiperidinium chloride were found to be acceptable. The steric hindrance of the solvation, characteristic for 2-alkoxy isomers, makes their separation from 3- or 4-alkoxy isomers possible, with the exception of methoxy derivatives.

The use of photogenerated iodine in determination of the dibazol content in solid and liquid dosage formulations

2021 ◽  
Vol 87 (2) ◽  
pp. 19-24
Author(s):  
E. V. Turusova
Keyword(s):  
Generation Time ◽  
Quantitative Estimation ◽  
Potato Starch ◽  
Analytical Signal ◽  
Acetate Buffer Solution ◽  
Molar Ratio ◽  
Buffer Solution ◽  
Solution Ph ◽  
Solid Dosage

A rapid method for the determination of Dibazol (bendazol hydrochloride) in liquid and solid dosage forms (DF) has been developed. The method is based on converting the drug into an analytical form and titrating the physiologically active compound (PAC) with a solution of photogenerated iodine obtained by irradiation of an auxiliary solution containing potassium iodide, a mixture of sensitizers (sodium eosinate: fluorescein: auramine, taken in a molar ratio of 1:1:1) and an acetate buffer solution (pH 5.6). A decrease in the titrant content in the cell due to interaction with Dibazol was recorded by a decrease in the current in the amperometric circuit. Stabilization of the current in the circuit indicated the completeness of the reaction, thus providing for estimation of the PAC content in a DF. Further irradiation of the solution and measurement of the generation time required to replenish the titrant loss in the cell also ensure the quantitative estimation of the PAC content in the preparation. The method has been tested on solid dosage form and sterile solutions of Dibazol intended for intramuscular and intravenous administration. A slight effect of stabilizers (hydrochloric acid, ethanol) and auxiliary substances (potato starch) present in the DF on the photogeneration of the titrant was observed. The determined Dibazol content in solid and liquid DF falls within the range recommended by the order of the Ministry of Health of the Russian Federation (26.10.2015 No. 751n) and OFS.1.4.2.0009.15, which indicates that the quality of the drug meets the GMP standards. The linear dependence of the analytical signal on the Dibazol concentration is observed in the range of 13.5 – 134.7 mg for the drug «Dibazol-UBF, tablets, 20 mg». The calculated limits of Dibazol detection and quantitative determination by changes in the current strength and generation time are (4.71; 3.56) and (14.26; 10.77) mg, respectively. The use of developed technique in the analysis of drugs containing Dibazol reduces both the time of single determination due to the absence of the need for standardization of solutions, and the cost of a single analysis, since it does not require the use of expensive equipment and reagents.

Determination of Trace Iron in Chinese Herbal Medicine Using CdS Quantum Dots as Fluorescence Probes

2012 ◽  
Vol 455-456 ◽  
pp. 1195-1199
Author(s):  
Yun Long Zeng ◽  
Xia Fei Li ◽  
Chun Ran Tang ◽  
Hao Wen Huang ◽  
Ya Jing Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fluorescence Probe ◽  
Copper Ion ◽  
Water Soluble ◽  
Fluorescence Probes ◽  
Cds Quantum Dots ◽  
Buffer Solution ◽  
Green Protocol ◽  
Quenching Method

A simple A green protocol for synthesis of high quality, water-soluble and biocompatible CdS QDs have been developed in aqueous solution with amylum as stabilizing agent. The QDs were characterized by AMF and spectral methods. A fluorescence quenching method was developed for determination of iron (ΙΙΙ) with water soluble CdS quantum dots (QDs) as fluorescence probe. In pH 8.5 boric acid–borax buffer solution, the QDs show a high selective to ferric ion. The common cations, such as Ca2+, Mg2+, Zn2+, Fe2+ et al, have no effect on interference but copper ion. The fluorescence intensity of the QDs decreased linearly with the iron (QDs ) concentration in the range of 200 μM to 60 nM with a detection limit of 20 nM. It has been applied to determinate of iron in Angelica, Astragalus, Shouwu, ligusticum wallichii and radix rehmanniae recen.

Effect of Sulfide Ions on the Corrosion Behaviour of Mild Steel in Acetate Buffer

1993 ◽  
Vol 58 (3) ◽  
pp. 547-554 ◽  
Author(s):  
Hyman H. Rehan ◽  
Said A. Salih ◽  
Hassan El-Daley ◽  
Ahmed G. Gad-Allah
Keyword(s):  
Mild Steel ◽  
Corrosion Behaviour ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Dissolution Rates ◽  
Buffer Solutions ◽  
Sulfide Ions

The corrosion behaviour of mild steel was investigated in acidic acetate buffer solution using impendance and potential measurements. It was found that there are two dissolution rates resulting from the duplex nature of the formed oxides. The dissolution rates were found to depend on the dissolving acetate buffer solution pH and the dissolution temperature. In all cases, the film thickness was found to decrease with time of corrosion according to the relation Cm-1 = (Cm0)-1 - kdt1/2. It was found that addition of sulfide ions increases the dissolution rate and increases the rate of hydrogen evolution reaction but does not affect the mechanism of cathodic process. The role of sulfide ions on the corrosion behaviour of steel in acetate buffer solutions is revealed by the complex plane impendance analysis.

scholarly journals Nickel(II) Selective PVC-Based Membrane Sensor Using a Schiff Base

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
B. Rezaei ◽  
H. Hadadzadeh ◽  
A. Azimi
Keyword(s):  
Schiff Base ◽  
Acetate Buffer Solution ◽  
Pvc Membrane ◽  
Sodium Tetraphenylborate ◽  
Buffer Solution ◽  
Membrane Sensor ◽  
Selective Determination ◽  
Nickel Determination ◽  
Chelating Reagent

A polyvinylchloride (PVC) membrane optode was prepared by using 1,2-di(o-salicylaldiminophenylthio)ethane (H2DSALPTE) as a chelating reagent for selective determination of Ni(II) ions. The optimized membranes incorporating H2DSALPTE as an ionophore, sodium tetraphenylborate (NaTPB) as an anion excluder, and tributyl phosphate (TBP) as a solvent mediator were prepared and applied for determination of Ni(II) ions. The membrane responded to Ni(II) ion by changing the color from yellow to green in an acetate buffer solution at pH 6.0. The best performance was observed when the membrane having a composition of 3.17% ligand, 31.64% PVC, 63.29% TBP, and 1.90% NaTPB. The membrane can be worked well over a wide concentration range from 1.0 × 10−5 to 5.0 × 10−3 M. The membrane exhibited a detection limit of 8.51 × 10−6 M, and the response time of the membrane was within 7–12 min depending on the concentration of Ni(II) ions. The selectivity of the probe towards nickel determination was found to be very good. Experimental results showed that the probe could be used as an effective tool in analyzing the Ni(II) content of water samples.

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