scholarly journals Comparative Assessment of the Analytical Parameters in Ascorbic Acid and Sulphite Assay at a Spectrographic Carbon Working Electrode

2018 ◽  
Vol 1 (1) ◽  
pp. 465-469
Author(s):  
Aurelia Magdalena Pisoschi ◽  
Aneta Pop
Keyword(s):  
Ascorbic Acid ◽  
Linear Response ◽  
Analytical Signal ◽  
Comparative Investigation ◽  
Comparative Assessment ◽  
Reduction Peak ◽  
Working Electrode ◽  
Relative Standard ◽  
Electro Oxidation ◽  
Analytical Range

Abstract The aim of this study is the comparative investigation of spectrographic carbon electrode’s viability as working electrode, in ascorbic acid and sulphite asssessment. Cyclic voltammetry involves a linear sweeping of the potential, the analytical signal being represented by the anodic oxidation /cathodic reduction peak of the analyte. For both analytes, the electro-oxidation resulted in an anodic peak, correlable with ascorbic acid / sulphite concentration. The analytical range of linear response corresponded to 0.07 - 10 mM for ascorbic acid and to 15.5 mg/L - 4 g/L for sulphite. The relative standard deviation RSD (%) was 2.71 % for ascorbic acid and 2.88 % for sulphite. The sensitivities, given by the slopes of the calibration graphs were 88.88 μA/mmole/L for ascorbic acid and 477.37 μA/g/L for sulphite.

scholarly journals Comparative sulfite assay by voltammetry using Pt electrodes, photometry and titrimetry: Application to cider, vinegar and sugar analysis

2018 ◽  
Vol 16 (1) ◽  
pp. 1248-1256 ◽  
Author(s):  
Aurelia Magdalena Pisoschi ◽  
Aneta Pop
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Techniques ◽  
Sodium Thiosulfate ◽  
Comparative Investigation ◽  
Ring Electrode ◽  
Linear Range ◽  
Lower Sensitivity ◽  
Brown Sugar ◽  
Working Electrode ◽  
Relative Standard

AbstractSulfite is a widely applied preservation agent, against oxidative decay in foodstuffs and beverages. Among the analytical methods applied, electrochemical techniques exploit its facility to undergo oxidation. This paper aims at the comparative investigation of the performances exhibited by three analytical methodologies: cyclic voltammetry at different Pt working electrodes, the volumetric method employing sodium thiosulfate as titrating agent and the photocolorimetric method relying on the reduction of Fe3+-orthophenanthroline complex by sulfite. The cyclic voltammetric assay was performed at Pt strip and Pt ring electrodes, by linearly sweeping the potential between -100 and 1,500 mV. The linear range corresponded to 7.5 mg L-1 – 4.0 g L-1 for Pt strip working electrode and to 15.5 mg L-1 – 4.0 g L-1 for Pt ring working electrode. Relative standard deviations smaller than 3% showed repeatability. RSD values smaller than 3% were also obtained in the photometric assay, but the latter was characterised by a narrower linear range. The Pt strip electrode allowed wider linear range and lower sensitivity, whereas the Pt ring electrode with Ag/AgCl reference in the same unit was characterised by better repeatability. Applications involved sulfite assay in vinegar, brown sugar and cider samples with consistency between cyclic voltammetry and titrimetry.

scholarly journals Picomolar-Level Melamine Detection via ATP Regulated CeO2 Nanorods Tunable Peroxidase-Like Nanozyme-Activity-Based Colorimetric Sensor: Logic Gate Implementation and Real Sample Analysis

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 178
Author(s):  
Benazir Chishti ◽  
Zubaida A. Ansari ◽  
Hassan Fouad ◽  
Othman Y. Alothman ◽  
Mohamed Hashem ◽  
...  
Keyword(s):  
Linear Response ◽  
Limit Of Detection ◽  
Logic Gate ◽  
Colorimetric Sensor ◽  
Blue Color ◽  
Neutral Ph ◽  
Colorimetric Response ◽  
Relative Standard ◽  
Functional Logic ◽  
Gate Sensor

The capability of functional logic operations is highly intriguing, but far from being realized owing to limited recognition element (RE) and complex readout signals, which limit their applications. In this contribution, for a visual colorimetric sensor for melamine (MEL) we described the construction of two- and three-input AND logic gate by exploiting the intrinsic peroxidase (POD)-like activity of CeO2 nanorods (NRs) (~23.04% Ce3+ fraction and aspect ratio (RTEM) of 3.85 ± 0.18) as RE at acidic pH (4.5). Further ATP piloted catalytic tuning of POD-like activity in CeO2 NRs employed for a functional logic gate-controlled MEL sensing at neutral pH (7.4). AND logic circuit operated MEL sensing record colorimetric response time of 15 min to produce blue color proportionate to MEL concentration. The fabricated nanozyme (CeO2)-based logic gate sensor probe for MEL at pH 4.5 showed a linear response from 0.004 nM to 1.56 nM with a limit of detection (LOD) of 4 pM; while translation from acidic to neutral pH (at 7.4) sensor exhibited linear response ranging from 0.2 nM to 3.12 nM with a LOD value of 17 pM. Through CeO2 POD-like nanozyme behavior under acidic and neutral pH, the fabricated logic gate sensor showed high affinity for MEL, generating prominent visual output with picomolar sensitivity, good reproducibility, and stability with relative standard deviation (RSD) <1% and 2%, respectively. A feasibility study in real samples (raw milk and milk powder) showed good recoveries with negligible matrix effect, an anti-interference experiment revealed sensor selectivity, highlighting robust sensor practical utility. With the merits of high sensitivity, specificity, low cost, and simplified sample processing, the developed logic-controlled colorimetric MEL sensing platform with appropriate modifications can be recognized as a potent methodology for on-site analysis of various food adulterants and related applications.

Flow-Through Fourier Transform Infrared Sensor for Total Hydrocarbons Determination in Water

2009 ◽  
Vol 63 (9) ◽  
pp. 1015-1021 ◽  
Author(s):  
David Pérez-Palacios ◽  
Sergio Armenta ◽  
Bernhard Lendl
Keyword(s):  
Fourier Transform ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Chlorinated Solvents ◽  
Analytical Signal ◽  
Fourier Transform Infrared ◽  
Minimal Sample ◽  
Relative Standard ◽  
Ft Ir ◽  
Flow Through

A new flow-through Fourier transform infrared (FT-IR) sensor for oil in water analysis based on solid-phase spectroscopy on octadecyl (C18) silica particles has been developed. The C18 non-polar sorbent is placed inside the sensor and is able to retain hydrocarbons from water samples. The system does not require the use of chlorinated solvents, reducing the environmental impact, and the minimal sample handling stages serve to ensure sample integrity whilst reducing exposure of the analyst to any toxic hydrocarbons present within the samples. Fourier transform infrared (FT-IR) spectra were recorded by co-adding 32 scans at a resolution of 4 cm−1 and the band located at 1462 cm−1 due to the CH2 bending was integrated from 1475 to 1450 cm−1 using a baseline correction established between 1485 and 1440 cm−1 using the areas as analytical signal. The technique, which provides a limit of detection (LOD) of 22 mg L−1 and a precision expressed as relative standard deviation (RSD) lower than 5%, is considerably rapid and allows for a high level of automation.

scholarly journals Electrochemical determination of ascorbic acid at p-phenylenediamine film-holes modified glassy carbon electrode

2015 ◽  
Vol 80 (9) ◽  
pp. 1161-1175 ◽  
Author(s):  
Bikila Olana ◽  
Shimeles Kitte ◽  
Tesfaye Soreta
Keyword(s):  
Ascorbic Acid ◽  
Detection Limit ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Linear Response ◽  
Modified Electrodes ◽  
Electrochemical Determination ◽  
Carbon Electrode

In this work the determination of ascorbic acid (AA) at glassy carbon electrode (GCE) modified with a perforated film produced by reduction of diazonium generated in situ from p-phenylenediamine (PD) is reported. Holes were intentionally created in the modifier film by stripping a pre-deposited gold nanoparticles. The modified electrodes were electrochemically characterized by common redox probes: hydroquinone, ferrocyanide and hexamineruthenium(III). The cyclic voltammetric and amperometric response of AA using the modified electrodes was compared with that of bare GCE. The bare GCE showed a linear response to AA in the concentration range of 5 mM to 45 mM with detection limit of 1.656 mM and the modified GCE showed a linear response to AA in the concentration range of 5 ?M to 45 ?M with detection limit of 0.123 ?M. The effect of potential intereferents on amperometric signal of AA at the modified GCE was examined and found to be minimal. The inter-electrode reproducibility, stability, and accuracy were determined. The modified electrode showed excellent inter-electrode reproducibility, accuracy and stability. The modified electrode reported is a promising candidate for use in electroanalysis of AA.

scholarly journals Iodometric Quantitative Analysis Method of Ascorbic Acid in Tablets

2019 ◽  
Vol 70 (10) ◽  
pp. 3555-3560
Author(s):  
Costinela Valerica Georgescu ◽  
Cristian Catalin Gavat ◽  
Doina Carina Voinescu
Keyword(s):  
Ascorbic Acid ◽  
Quantitative Analysis ◽  
Standard Deviation ◽  
Statistical Significance ◽  
The Body ◽  
Water Soluble ◽  
International Standards ◽  
Titration Method ◽  
Normal Limits ◽  
Relative Standard

Ascorbic acid is a water-soluble vitamin provided with strong antioxidant action, that fulfills an important immune protective role of the body against infections and prevents various cancers appearance. The main goal of this study was to exactly quantify pure ascorbic acid in tablets of two pharmaceuticals. Proposed objective consisted in improvement and application of a iodometric titration method in ascorbic acid quantitative analysis. Ascorbic acid content per tablet in both studied pharmaceuticals was 173.84 mg, very close to official stated amount of active substance (180 mg). Allowed percentage deviation from declared content of pure ascorbic acid was only 3.42 %, below maximum value of � 5 % imposed by Romanian Pharmacopoeia 10-th Edition, according to European and International standards. Statistical analysis confirmed experimental obtained results and revealed low Standard Error value SE = 0.214476, which has fallen within normal limits. Confidence Level value (95.0 %) = 0.551328 and Standard Deviation SD = 0.525357. were within normal range of values. Relative Standard Deviation (Coefficient of variation or homogeneity) RSD = 26.268% was found below maximum range of accepted values (30-35%). P value = 7.44. 10-6 was located within normal limits, P [ 0.001, so the experimental obtained results has shown highest statistical significance. Thus, studied titration method can be successfully used in quantitative analysis of ascorbic acid from different samples.

Comparative assessment of synthetic strategies toward active platinum–rhodium–tin electrocatalysts for efficient ethanol electro-oxidation

2015 ◽  
Vol 294 ◽  
pp. 299-304 ◽  
Author(s):  
Nina Erini ◽  
Paul Krause ◽  
Manuel Gliech ◽  
Ruizhi Yang ◽  
Yunhui Huang ◽  
...  
Keyword(s):  
Comparative Assessment ◽  
Electro Oxidation

Copper Amalgam Working Electrode for Voltammetric Determination of Selenite

2021 ◽  
Vol 874 ◽  
pp. 35-44
Author(s):  
Ria Sri Rahayu ◽  
Meuthia Khelfa Pramesti ◽  
Adib Hasanawi ◽  
Dian Ayu Setyorini ◽  
Muhammad Yudhistira Azis
Keyword(s):  
Statistical Tests ◽  
Stripping Voltammetry ◽  
Good Precision ◽  
Linear Calibration ◽  
Working Electrode ◽  
Relative Standard ◽  
Significant Difference ◽  
Square Wave Stripping Voltammetry ◽  
Recovery Percentage ◽  
Aas Method

Selenium is one of the heavy metal pollutants in the aquatic environment. Selenite is a form of inorganic selenium, which is very poisonous to living things. Therefore, we need a method that selectively identify selenite to determine its concentration in water. In this study, a square wave stripping voltammetry was used to measure selenite concentration using copper amalgam working electrode. The optimum measurement parameters were obtained at a deposition potential of –450 mV and a deposition time of 800 seconds. This analysis method had good precision with a relative standard deviation (% RSD) of 4.89%. Linear calibration curves are shown in the range 0.03 mM – 0.10 mM with R2 of 0.988 and in the range of 0.10 mM – 0.70 mM with R2 of 0.995 and a detection limit of 9.0 µM. The standard selenite solution was measured with a recovery percentage of 96.67%. The same solution was measured using the HG-AAS method and the recovery percentage was 96.35%. Statistical tests using the t-test showed that the two results did not have a significant difference with a 95% confidence limit. Thus, the voltammetry method using copper amalgam working electrode can be used as an alternative method for determining selenite, as it is cheaper and simpler than the HG-AAS method.

Improved Apparatus for Rapid Mercury Determination by Cold Vapor Atomic Absorption Spectrometry

1983 ◽  
Vol 66 (5) ◽  
pp. 1117-1120
Author(s):  
Lawrence Kupchella ◽  
Augusta Syty ◽  
John J Mahfood
Keyword(s):  
Atomic Absorption ◽  
Analytical Signal ◽  
Absorption Spectrometry ◽  
Water Quality Control ◽  
Injection Port ◽  
Cold Vapor ◽  
Cold Vapor Atomic Absorption ◽  
Relative Standard ◽  
Atomic Absorption Spectrometric

Abstract A glass reaction vessel is described and the convenience and simplicity of its use in cold vapor atomic absorption spectrometric determination of mercury are pointed out. The vessel is easy to construct and requires only 15 s for collection of the analytical signal. It provides for continuous flow of carrier gas, and contains a septum-covered sample injection port, a buret for rapid introduction of reagent, and a drain stopcock. Using this apparatus, the relative standard deviation is 2.9% at the 40 ng Hg/mL level. The detection limit is 1 ng/mL. Applicability of the apparatus is proved by analysis of 3 commercial waste water quality control samples.

scholarly journals Voltammetric determination of the neonicotinoid insecticide thiamethoxam using a tricresyl phosphate-based carbon paste electrode

2010 ◽  
Vol 75 (5) ◽  
pp. 681-687 ◽  
Author(s):  
Zsigmond Papp ◽  
Valéria Guzsvány ◽  
Szymon Kubiak ◽  
Andrzej Bobrowski ◽  
Luka Bjelica
Keyword(s):  
Carbon Paste Electrode ◽  
Analytical Signal ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Carbon Paste ◽  
Tricresyl Phosphate ◽  
Relative Standard ◽  
Neonicotinoid Insecticide ◽  
Paste Electrode

The objective of the work was to investigate the possibility of using a tricresyl phosphate-based carbon paste electrode for the direct voltammetric determination of the neonicotinoid insecticide thiamethoxam. The analyte was determined by differential pulse voltammetry in Britton-Robinson buffer pH 7.0 in the concentration range of 3.72 - 41.5 ?g mL-1. The reproducibility of the analytical signal at the 7.29 ?g mL-1 level was characterized by a relative standard deviation of 1.3 %. The applicability of the developed method was evaluated by determining thiamethoxam in a river water sample and a commercial formulation Actara 25 WG.

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