scholarly journals Gold-Modified Micellar Composites as Colorimetric Probes for the Determination of Low Molecular Weight Thiols in Biological Fluids Using Consumer Electronic Devices

2021 ◽  
Vol 11 (6) ◽  
pp. 2705
Author(s):  
Elli A. Akrivi ◽  
Athanasios G. Vlessidis ◽  
Dimosthenis L. Giokas ◽  
Nikolaos Kourkoumelis
Keyword(s):  
Cationic Surfactant ◽  
Electrostatic Interactions ◽  
Biological Fluids ◽  
Low Cost ◽  
Standard Addition ◽  
Microtiter Plate ◽  
Ammonium Bromide ◽  
Cetyltrimethyl Ammonium ◽  
Light Absorbance

This work describes a new, low-cost and simple-to-use method for the determination of free biothiols in biological fluids. The developed method utilizes the interaction of biothiols with gold ions, previously anchored on micellar assemblies through electrostatic interactions with the hydrophilic headgroup of cationic surfactant micelles. Specifically, the reaction of AuCl4− with the cationic surfactant cetyltrimethyl ammonium bromide (CTAB) produces an intense orange coloration, due to the ligand substitution reaction of the Br− for Cl− anions, followed by the coordination of the AuBr4− anions on the micelle surface through electrostatic interactions. When biothiols are added to the solution, they complex with the gold ions and disrupt the AuBr4−–CTAB complex, quenching the initial coloration and inducing a decrease in the light absorbance of the solution. Biothiols are assessed by monitoring their color quenching in an RGB color model, using a flatbed scanner operating in transmittance mode as an inexpensive microtiter plate photometer. The method was applied to determine the biothiol content in urine and blood plasma samples, with satisfactory recoveries (i.e., >67.3–123% using external calibration and 103.8–115% using standard addition calibration) and good reproducibility (RSD < 8.4%, n = 3).

Microextraction and Chromatographic Analysis of Budesonide Epimers in Exhaled Breath Condensate

2020 ◽  
Vol 16 (8) ◽  
pp. 1032-1040
Author(s):  
Laleh Samini ◽  
Maryam Khoubnasabjafari ◽  
Mohamad M. Alimorad ◽  
Vahid Jouyban-Gharamaleki ◽  
Hak-Kim Chan ◽  
...  
Keyword(s):  
Biological Fluids ◽  
Exhaled Breath Condensate ◽  
Low Cost ◽  
Exhaled Breath ◽  
Chromatography Method ◽  
Extraction Solvent ◽  
Drug Concentrations ◽  
Dispersive Liquid Liquid Microextraction ◽  
Breath Condensate

Background: Analysis of drug concentrations in biological fluids is required in clinical sciences for various purposes. Among other biological samples, exhaled breath condensate (EBC) is a potential sample for follow up of drug concentrations. Methods: A dispersive liquid-liquid microextraction (DLLME) procedure followed by a validated liquid chromatography method was employed for the determination of budesonide (BDS) in EBC samples collected using a homemade setup. EBC is a non-invasive biological sample with possible applications for monitoring drug concentrations. The proposed analytical method is validated according to the FDA guidelines using EBC-spiked samples. Its applicability is tested on EBC samples collected from healthy volunteers receiving a single puff of BDS. Results: The best DLLME conditions involved the use of methanol (1 mL) as a disperser solvent, chloroform (200 μL) as an extraction solvent, and centrifugation rate of 3500 rpm for 5 minutes. The method was validated over a concentration range of 21-210 μg·L-1 in EBC. Inter- and intra-day precisions were less than 10% where the acceptable levels are less than 20%. The validated method was successfully applied for the determination of BDS in EBC samples. Conclusion: The findings of this study indicate that the developed method can be used for the extraction and quantification of BDS in EBC samples using a low cost method.

Genome Analysis of Mungbean [Vigna radiata (L.) Wilczek] using Simple Sequence Repeats (SSR) Mapping Data

2021 ◽  
Author(s):  
Babita Rani ◽  
Renu Singh ◽  
Minakshi Jattan ◽  
Shubham Kumar ◽  
Ram Kumar
Keyword(s):  
Genetic Diversity ◽  
Agricultural Research ◽  
Ammonium Bromide ◽  
Breeding Lines ◽  
Iron And Zinc ◽  
Zinc Concentrations ◽  
Increase Productivity ◽  
Cetyltrimethyl Ammonium ◽  
Simple Sequence

Background: Agricultural research chiefly focuses on the ways to increase productivity of staple food crops like wheat and rice, but still there are crops where research focus is meagre like nutritionally important mungbean crop grown by marginal farmers in crop rotation systems. Mungbean is leguminous crop which is high in protein content thus it offers health benefits at cheaper rates. The present work emphasizes on finding genetic diversity in mungbean germplasm on the basis of chemical and molecular analysis for micronutrients variation (iron and zinc). The identified molecular markers having linkage with high iron and zinc concentrations in the seeds can prove helpful in expansion of biofortification programme.Methods: Fifty-one green gram genotypes viz. varieties released from CCS Haryana Agricultural University (HAU), Hisar, Punjab Agricultural University (PAU), Ludhiana, Indian Institute of Pulse Research (IIPR), Kanpur and some advanced breeding lines were included in the study. Acid digested samples were used for determination of Fe and Zn by Atomic Absorption Spectrophotometer. Young seedlings leaves were used for isolation of genomic DNA using 2% CTAB (cetyltrimethyl ammonium bromide). Result: Total of fifty-one mungbean genotypes were tested using fifty simple sequence repeat (SSR) primers. Out of fifty primers screened, 16 primers generated 35 bands. Iron (Fe) and zinc (Zn) in mungbean lines was 36.90 to 107.1 mg/kg and 14.2 to 53.8 mg/kg respectively. The molecular studies based on SSR markers also indicates existence of ample genetic diversity at molecular level.

scholarly journals Spectrophotometric and Smartphone-Assisted Determination of Phenolic Compounds Using Crude Eggplant Extract

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4407 ◽  
Author(s):  
M.A. Morosanova ◽  
A.S. Bashkatova ◽  
E.I. Morosanova
Keyword(s):  
Phenolic Compounds ◽  
Chlorogenic Acid ◽  
Caffeic Acid ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Biological Fluids ◽  
Low Cost ◽  
Analytical Signal ◽  
Polyphenol Oxidase Activity

In order to develop a simple, reliable and low cost enzymatic method for the determination of phenolic compounds we studied polyphenol oxidase activity of crude eggplant (S. melongena) extract using 13 phenolic compounds. Catechol, caffeic and chlorogenic acids, and L-DOPA have been rapidly oxidized with the formation of colored products. Monophenolic compounds have been oxidized at a much slower speed. Ferulic acid, quercetin, rutin, and dihydroquercetin have been found to inhibit polyphenol oxidase activity of crude eggplant extract. The influence of pH, temperature, crude eggplant extract amount, and 3-methyl-2-benzothiazolinone hydrazone (MBTH) concentration on the oxidation of catechol, caffeic acid, chlorogenic acid, and L-DOPA has been investigated spectrophotometrically. Michaelis constants values decrease by a factor of 2 to 3 in the presence of MBTH. Spectrophotometric (cuvette and microplate variants) and smartphone-assisted procedures for phenolic compounds determination have been proposed. Average saturation values (HSV color model) of the images of the microplate wells have been chosen as the analytical signal for smartphone-assisted procedure. LOD values for catechol, caffeic acid, chlorogenic acid, and L-DOPA equaled 5.1, 6.3, 5.8 and 30.0 µM (cuvette procedure), 12.2, 13.2, 13.2 and 80.4 µM (microplate procedure), and 23.5, 26.4, 20.8 and 120.6 µM (smartphone procedure). All the variants have been successfully applied for fast (4-5 min) and simple TPC determination in plant derived products and L-DOPA determination in model biological fluids. The values found with smartphone procedure are in good agreement with both spectrophotometric procedures values and reference values. Using crude eggplant extract- mediated reactions combined with smartphone camera detection has allowed creating low-cost, reliable and environmentally friendly analytical method for the determination of phenolic compounds.

Development of a Dispersive Liquid–Liquid Microextraction Method Combined with UV-Visible Spectrophotometry for Determination of Trace Aluminum(III) in Water, Wastewater, Food, Biological, and Pharmaceutical Samples

2017 ◽  
Vol 100 (1) ◽  
pp. 224-229 ◽  
Author(s):  
Nasrin Taghipour Birgani ◽  
Shahla Elhami
Keyword(s):  
Dynamic Range ◽  
Sample Volume ◽  
Ammonium Bromide ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Reagent Blank ◽  
Uv Visible ◽  
Cetyltrimethyl Ammonium ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

Abstract A simple and sensitive method was proposed for the preconcentration of trace levels of Al(III) prior to its determination by spectrophotometry, based on dispersive liquid–liquid microextraction. The complexation of the Al(III) was performed by chelation with Eriochrome Cyanine R (ECR). In this method, cetyltrimethyl ammonium bromide (CTAB) as a dispersant was dissolved in chloroform as an extractant solvent, and then the solution was rapidly injected by a syringe into the samples containing Al(III), which had already been complexed by ECR at optimized pH. Various parameters were studied and optimized for a 10 mL sample volume. Under the optimum conditions, the LOD (3 times the SD of 10 replicate readings of the reagent blank) and the dynamic range of the calibration obtained were 0.2 ng mL−1 (7 nM) and 1.0–80.0 ng mL−1, respectively. The RSDs for eight replicate determinations of10 and 60 ng mL−1 of Al(III) were 3.3 and 1.8%, respectively. This strategy was successfully applied to determine the Al concentration in water, wastewater,yogurt, apple, carrot, celery, bread, potato, urine, and Al–Mg syrup samples.

scholarly journals Development of membrane electrodes for selective determination of lisinopril in pharmaceuticals

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiah
Keyword(s):  
Enzyme Inhibitor ◽  
Limit Of Detection ◽  
Low Cost ◽  
Ion Pairs ◽  
Standard Addition ◽  
Phosphomolybdic Acid ◽  
Selective Determination ◽  
Accuracy And Precision ◽  
Selective Membrane

Abstract Background Lisinopril (LNP) is an angiotensin-converting enzyme inhibitor used as anti-hypertensive, cardiovascular, in anti-prophylactic and anti-diabetic nephropathy drug. Development of two new, simple, low cost, and selective membrane-based ion-selective electrodes has been proposed for the determination of LNP in pharmaceuticals. Methods The electrodes are based on poly(vinyl)chloride membrane doped with LNP-phosphotungstic acid (LNP-PTA) and LNP-phosphomolybdic acid (LNP-PMA) ion-pairs as molecular recognition materials. Results The developed LNP-PTA and LNP-PMA electrodes are applicable for the determination of LNP over the linear range of 5 × 10−5–2.4 × 10−3 mol l−1. The working pH ranges to measure potentials were 2.5 to 6.4 and 2.3 to 6.0 for LNP-PTA and LNP-PMA ISEs, respectively. The electrodes displayed the rapid Nernstian responses as revealed by the values of slopes 55.06 and 52.39 mV/decade, with limit of detection (LOD) values of 1.2 × 10−5 and 1.18 × 10−5 mol l−1 for LNP-PTA and LNP-PMA electrodes, respectively. The limits of quantitation (LOQ) values have also been calculated for both the electrodes. The developed electrodes have potential stability for up to 1 month and emerged as highly selective for the determination of LNP over other spiked ions and compounds. Conclusions The proposed electrodes have been validated and found that they are suitable for the determination of LNP in pharmaceuticals in pure form and in dosage forms. The results obtained in the analysis of LNP using proposed electrodes have been compared statistically with reference method’s results to assess the accuracy and precision. Robustness and ruggedness of the developed electrodes have also been checked and found satisfactory. The recovery studies have been performed by standard addition procedure to assess the role of excipients in tablets containing LNP and the results obtained are satisfactory.

Voltammetric method for determination of glutathione on a gold-carbon-containing electrode

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 28-34
Author(s):  
A. S. Gashevskaya ◽  
E. V. Dorozhko ◽  
E. I. Korotkova ◽  
E. A. Pashkovskaya ◽  
O. A. Voronova ◽  
...  
Keyword(s):  
High Performance ◽  
Biological Fluids ◽  
Low Cost ◽  
Pharmaceutical Preparations ◽  
Electrochemical Methods ◽  
Voltammetric Method ◽  
Indirect Determination ◽  
Biochemical Processes ◽  
Glutathione Determination

Glutathione (GSH) is one of the most important thiol-containing antioxidants involved into various biochemical processes in the human body. Glutathione determination in biological fluids (saliva, urine, serum) and pharmaceutical preparations is rather important for clinical practice. Various analytical methods — spectrophotometry, fluorimetry, high-performance liquid chromatography, NMR spectroscopy, capillary electrophoresis and electrochemical methods — are widely used for this purpose. Electrochemical methods are characterized by easy implementation, low cost and possibility of miniaturization. The electrochemical behavior of reduced (GSH) and oxidized (GSSG) glutathione on a gold-carbon-containing electrode (AuCE) was studied using cathodic voltammetry with different methods of removing oxygen from an electrochemical cell: nitrogen sparging and addition of sodium sulfite (4 mol/dm3). It has been shown that traces of H2O2 that remain in the near-electrode layer on the AuCE even after oxygen removal influence the electrochemical properties of GSH at a cathode sweep of the potential from 0 to –1.8 V: GSH is oxidized by H2O2 to GSSG, the most important product of this reaction is O2. An indirect determination of GSH by the current of oxygen reduction in the Na2SO3 medium in the concentration range from 0.5 × 10–8 to 4.2 × 10–8 mol/dm3 with a detection limit of 2.5 × 10–9 mol/dm3 is proposed. The developed voltammetric method is approved for the determination of GSH in certain pharmaceutical preparations.

Effect of Cetyltrimethyl Ammonium Bromide on Electrochemical Determination of Dexamethasone

2010 ◽  
Vol 22 (20) ◽  
pp. 2330-2338 ◽  
Author(s):  
Rajendra N. Goyal ◽  
Sanghamitra Chatterjee ◽  
Anoop Raj Singh Rana
Keyword(s):  
Electrochemical Determination ◽  
Ammonium Bromide ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Cetyltrimethyl Ammonium
Sign in / Sign up

Export Citation Format

Share Document