Ascorbic Acid as a Standard for Iodometric Titrations. An Analytical Experiment for General Chemistry

Silva, César R.; Simoni, José A.; Collins, Carol H.; Volpe, Pedro L. O.

doi:10.1021/ed076p1421

Cited by 48 publications

(30 citation statements)

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“…Vitamin C content was determined by iodine titration method (Silva, Simoni, Collins, & Volpe, 1999). Briefly, 25 g of grape sample was mixed with 50 ml distilled water, homogenized in a blender, and then made up to 250 ml with distilled water.…”

Section: Analyses Of Changes In Physicochemical Properties Of Grapementioning

confidence: 99%

Efficacy of photoactivated curcumin to decontaminate food surfaces under blue light emitting diode

Aurum

Nguyen

2019

J Food Process Engineering

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The efficacy of photoactivated curcumin in decontaminating food surfaces using a 465 nm light emitting diode (LED) light source was investigated. Under studied conditions, LED illumination alone had negligible antibacterial effects while photoactivated curcumin exhibited strong bactericidal activities against Escherichia coli. Minimum inhibitory concentration of photosensitized curcumin against E. coli on nutrient agar surface at a concentration of 1.5 × 105 cfu/cm2 was estimated to be 1.60 × 10−3 M, combined with irradiation of 27.2 J/cm2 at 465 nm. Bacterial inactivation kinetics could be described by a Weibull model (R2 = 0.979–0.999, RMSE = 0.019–0.229). When the treatment was applied on grape surface, the efficiency was lower as compared to that on the agar surface. Photoactivation enhanced quality retention of the samples during storage with significant preservation of vitamin C, color, texture, and reduction of weight losses. Practical applications The study provides an alternative method for food surface decontamination. Inactivation of pathogens and spoilage microorganism by combined visible LED light source and natural photosensitizers minimizes the adverse processing effects on organoleptic and physicochemical quality of the treated foods. The approach could be further optimized, scaled up, and applied in food industries.

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Section: Analyses Of Changes In Physicochemical Properties Of Grapementioning

confidence: 99%

Efficacy of photoactivated curcumin to decontaminate food surfaces under blue light emitting diode

Aurum

Nguyen

2019

J Food Process Engineering

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“…Ascorbic acid content was determined by redox titration method using iodine solution according to Silva et al [26].…”

Section: Ascorbic Acid Determinationmentioning

confidence: 99%

Nutritional, Chemical and Organoleptical Characteristics of Low-Calorie Fruit Nectars Incorporating Stevioside as a Natural Sweetener

Barakat¹,

Al-Furaydi²,

Al-Harbi³

et al. 2017

FNS

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The study is aiming at preparation of low-calorie fruit nectars for diabetes and weight maintaining approaches as well as consumer satisfaction. Therefore, twenty low-calorie fruit-based formulated nectars were prepared mainly from orange, pomegranate, guava and mango pulps which sweetened with sucrose or sucrosereplaced at 25%, 50%, 75% and 100% using stevioside. Primitively, the yield of fresh fruits had been calculated. Consequently, nutritional, chemical and organoleptical characteristics of prepared fruit nectars have been determined. Results indicated that total solids content was in range of 5.57% -13.20%, 9.90% -14.37%, 8.25% -13.27% and 8.25% -16.50% for orange, pomegranate, guava and mango nectars, respectively. Dependently, caloric value resulted 21.57 to 51.08, 38.31 to 55.62, 31.93 27.53, 15.73 to 18.32, 25.72 to 30.87 and 18.07 to 20.98 for orange, pomegranate, guava and mango nectars, respectively. The results of organoleptical attributes showed no effect of sugar substituting by stevioside on color, odor and mouth feel. The most dramatic effect of sugar substituting had been observed on taste, bitter after taste and the overall acceptability of prepared nectars with high

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“…The ascorbic acid concentration in the commercial Vitamin C formulation, which prescribed amount is 1 g/tablet was determined by amperometry (1.02 0.01 g/tablet) and further compared with iodometric titration method (0.99 0.03 g/tablet). 42 The presence of other substances in the Vitamin C tablets, such as citric acid, lemon flavor, orange flavor, sodium bicarbonate, sodium cyclamate and quinoline yellow, did not affect the results. 43 The performance of the CA-TiO 2 MB modified electrode in comparison with others amperometric sensors, based on carbon paste electrodes for the determination of AA, were also shown in Table 1.…”

Section: Amperometric Detectionmentioning

confidence: 86%

Methylene blue immobilized on cellulose acetate with titanium dioxide: an application as sensor for ascorbic acid

Hoffmann¹,

Dias²,

Rodrigues³

et al. 2008

J. Braz. Chem. Soc.

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Neste trabalho, o corante azul de metileno foi imobilizado na superfície do acetato de celulose modificado com dióxido de titânio produzindo um material híbrido sólido denominado de CA-TiO 2 MB. O experimento produziu uma quantidade de 1,8 mmol g -1 de TiO 2 incorporado no acetato de celulose e uma quantidade de 0,170 0,005 mmol g -1 de azul de metileno adsorvido na superfície do CA-TiO 2 . Um eletrodo de pasta de carbono desse material foi usado para estudar a oxidação eletrocatalítica do ácido ascórbico pelas técnicas de voltametria cíclica e cronoamperometria. O pH da solução não afetou o potencial de pico de anódico nem a corrente de pico anódico ao variar de 3,0 a 7,0. A oxidação do analito ocorreu em 75 mV versus ECS em solução de KCl 1,0 mol L -1 e pH 7,0. A intensidade da corrente de pico anódico variou com a concentração de ácido ascórbico na faixa de 5,0 10 -4 mol L -1 to 4,5 10 -3 mol L . A resposta do eletrodo foi muito rápida, com um tempo decorrido de 1,0 s, mostrando potencial para ser utilizado como um sensor eletroquímico para a determinação de ácido ascórbico em produtos comerciais.In this work, methylene blue dye was immobilized on the surface of cellulose acetate modified with titanium dioxide, producing a solid hybrid material designated as CA-TiO 2 MB. The experiment yielded an amount of 1.8 mmol g -1 of TiO 2 incorporated in the cellulose acetate and an amount of 0.170 0.005 mmol g -1 of methylene blue adsorbed onto CA-TiO 2 surface. A carbon paste electrode of this material was used to study the electrocatalytic oxidation of ascorbic acid by cyclic voltammetric and chronoamperometric techniques. The pH of the solution had no effect on the anodic peak potential and anodic peak current when ranging from 3.0 to 7.0. The oxidation of the analyte occurred at 75 mV versus SCE in 1.0 mol L -1 KCl solution and pH 7.0. The intensity of the anodic peak current varied with the concentration of ascorbic acid from 5.0 10 -4 mol L -1 to 4.5 10 -3 mol L -1 and a linear correlation was observed, with a detection limit of 15 µmol L -1 , quantification limit of 50 µmol L -1 and a sensitivity of 7.1 µA L mol -1. The electrode response was very fast, with an elapsed time of about 1.0 s, showing the potentiality to be utilized as an electrochemical sensor for determination of ascorbic acid in commercial samples.Keywords: methylene blue, modified cellulose acetate, titanium dioxide, carbon paste electrode, ascorbic acid IntroductionThe development of sensors that allow the measurements of some analyte, which presents analytical or environmental interest, has continued to be of major concern during the past two decades. They use as electrochemical mediator species makes possible the attempt to exert more control over the chemical nature of an electrode and to attain the selectivity of electrochemical measurements. This development has helped the measurement of important analytes in medicine, pharmacy, manufactured food and other areas. The most common material that is usually employed as an inert support for th...

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Ascorbic Acid as a Standard for Iodometric Titrations. An Analytical Experiment for General Chemistry

Cited by 48 publications

References 4 publications

Efficacy of photoactivated curcumin to decontaminate food surfaces under blue light emitting diode

Efficacy of photoactivated curcumin to decontaminate food surfaces under blue light emitting diode

Nutritional, Chemical and Organoleptical Characteristics of Low-Calorie Fruit Nectars Incorporating Stevioside as a Natural Sweetener

Methylene blue immobilized on cellulose acetate with titanium dioxide: an application as sensor for ascorbic acid

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