scholarly journals Determination of Antioxidant Activity of Vitamin C by Voltammetric Methods

Proceedings ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 23 ◽  
Author(s):  
Klaudia Suliborska ◽  
Monika Baranowska ◽  
Agnieszka Bartoszek ◽  
Wojciech Chrzanowski ◽  
Jacek Namieśnik
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Chemical Properties ◽  
Differential Pulse ◽  
Antioxidant Compounds ◽  
Redox Active ◽  
Physical And Chemical ◽  
Kinetics Of ◽  
Voltammetric Methods

Voltammetric methods—cyclic (CV) and differential pulse voltammetry (DPV) are considered the most appropriate way to evaluate antioxidant activity of redox active compounds. They provide information about both mechanism and kinetics of electrochemical oxidation of antioxidants as well as their physical and chemical properties such as the redox potential or the number of electrons transferred. These methods are helpful for understanding the mechanisms of oxidation or reduction processes of antioxidant compounds. This work presents the electrochemical properties of vitamin C obtained by both CV and DPV methods.

THE IMPORTANCE OF THE RED BOOK OF SOILS FOR MONITORING AND JUSTIFICATION OF CONSERVATION MEASURES

2020 ◽  
Author(s):  
O.S. Bezuglova ◽  
Keyword(s):  
Chemical Properties ◽  
Natural State ◽  
Soil Maps ◽  
Rostov Region ◽  
Conservation Measures ◽  
Background Data ◽  
The Russian Federation ◽  
Physical And Chemical ◽  
And Chemical Properties

Rostov Region belongs to the highly protected natural territories characterized by the continuous plowing. There territories are the only reserves with the soils preserved in their natural state. However, these areas often lack detailed information about the soils quality and composition. Surveying soils on these territories is crucial for determination of their basic physical and chemical properties. The resulted compilation of soil maps could lay a foundation for creating the Red Book of Soils and the formation of a section in the soil-geographical database of the Russian Federation. Subsequently, such information can be used as a background data for the main types of soils in the region. It will be also valuable during monitoring and justification of conservation measures.

scholarly journals Quality Attributes of Malaysia Purple-Fleshed Sweet Potato at Different Peel Condition

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 872
Author(s):  
Nurfarhana Shaari ◽  
Rosnah Shamsudin ◽  
Mohd Zuhair Mohd Nor ◽  
Norhashila Hashim
Keyword(s):  
Vitamin C ◽  
Sweet Potato ◽  
Dry Matter ◽  
Nutritional Value ◽  
Amylose Content ◽  
Starch Content ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

In this study, physical and chemical properties (dry matter, ash, moisture, protein, fat, fiber, carbohydrate, starch, amylose, and vitamin C) of sweet potato tuber and flour of Anggun 1 cultivar were evaluated at different conditions. During peeling, the tuber and flour were processed subjected to three different conditions, which were unpeeled tubers (C1), peeled tubers (C2), and skin of tuber only (C3). From the results, the highest (p < 0.05) dry matter was observed in C1 while higher contents of ash, moisture, and protein were found in C3. Regarding the fat and vitamin C content, no significant differences (p > 0.05) were found between each condition. The highest fiber, carbohydrate, and amylose content (p < 0.05) were found in C1. The C1 and C2 reflected significantly higher (p < 0.05) starch content. Overall, these results provide important information about the peeling effect on the physical and chemical properties of Anggun 1. The information could be used as adding value to healthy food in the Malaysian diet due to the nutritional value of sweet potato.

scholarly journals Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner
Keyword(s):  
Hydraulic Conductivity ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Treated Wastewater ◽  
Soil Aggregate Stability ◽  
Irrigation Effects ◽  
Physical And Chemical ◽  
The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

Di-imide: Some Physical and Chemical Properties, and the Kinetics and Stoichiometry of the Gas-phase Decomposition

1973 ◽  
Vol 51 (21) ◽  
pp. 3605-3619 ◽  
Author(s):  
C. Willis ◽  
R. A. Back
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Chemical Properties ◽  
Phase Decomposition ◽  
Important Intermediate ◽  
Long Lifetime ◽  
Physical And Chemical ◽  
Text Formation ◽  
Kinetics Of

Preparation of di-imide by passing hydrazine vapor through a microwave discharge yields mixtures with NH3 containing typically about 15% N2H2, estimated from the gases evolved on decomposition. The behavior of the mixture (which melts at −65 °C) on warming from −196 to −30 °C suggests a strong interaction between the components. Measurements of magnetic susceptibility and e.p.r. experiments showed that N2H2 is not strongly paramagnetic, which with other observations points to a singlet rather than a triplet ground-state.Di-imide can be vaporized efficiently, together with NH3, by rapid warming, and the vapor is surprisingly long-lived, with a typical half-life of several minutes at room temperature. The near-u.v. (3200–4400 Å) absorption spectrum of the vapor was photographed; it shows well-defined but diffuse bands, with εmax = 6(± 3) at 3450 Å.Di-imide decomposes at room temperature in two ways:[Formula: see text][Formula: see text]Formation of NH3 was not observed but cannot be ruled out. The decomposition of the vapor is complicated by a sizeable and variable decomposition that occurs rapidly during the vaporization. The stoichiometry of this and the vapor-phase decomposition depends on total pressure and di-imide concentration. The kinetics of the decomposition of the vapor were studied from 22 to 200 °C by following the disappearance of N2H2 by absorption of light at 3450 Å, or the formation of N2H4 by absorption at 2400 Å, and by mass spectrometry. The kinetics are complex and can be either first- or second-order, or mixed, depending on surface conditions. The effect of olefin additives on the decomposition was studied, and is also complex.Mechanisms for the decomposition are discussed, including the possible role of trans-cis isomerization. The relatively long lifetime found for di-imide in the gas phase suggests that it may be an important intermediate in many reactions of hydronitrogen systems.

In search of an optimum plutonium density measurement fluid

2009 ◽  
Vol 97 (4-5) ◽  
Author(s):  
K. M. Dziewinska ◽  
A. M. Peters ◽  
J. A. La Verne ◽  
P. Martinez ◽  
J. J Dziewinski ◽  
...  
Keyword(s):  
National Laboratory ◽  
Density Measurement ◽  
Chemical Properties ◽  
Decomposition Products ◽  
Los Alamos National Laboratory ◽  
Corrosion Rates ◽  
Physical And Chemical ◽  
Near Future ◽  
Plutonium Metal

AbstractDensity measurements of plutonium metal and its alloys are performed at Los Alamos National Laboratory (LANL) using a technique based on the Archimedes principle. The goal is to find and characterize a fluid for density determination of large objects made of plutonium to replace the currently used monobromobenzene. Physical and chemical properties must be considered while selecting the fluid. Chemical properties of the fluid must ensure low corrosion rates and good resistance to radiological decomposition. The study was carried on to evaluate the corrosion rates of Pu metal cause by FC-43 and the FC-43 decomposition products of radiolysis. The results of these studies proved favourable for this application. The evaluation of the surface reactions between FC-43 and Pu metal will be conducted in the near future.

scholarly journals UJI AKTIVITAS ANTIOKSIDAN EKSTRAK ETANOL BULBUS BAWANG DAYAK (Eleutherine americana Merr) DENGAN METODE DPPH (1,1-Diphenyl-2-Picrylhydrazyl)

PHARMACON ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 451
Author(s):  
Rizkah V. Mokoginta ◽  
Herny E. I. Simbala ◽  
Karlah L.R Mansauda
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Ethanol Extract ◽  
Antioxidant Compounds ◽  
Onion Plant ◽  
Dpph Method ◽  
Ic50 Values ◽  
Experimental Laboratory ◽  
Ethanol Extracts ◽  
Eleutherine Americana

ABSTRACTDayak onion plant (Eleutherine americana Merr.) or commonly called forest onion is a typical plant of Central Kalimantan that has been used by local peoples for cure a various types of diseases. This study aims to determine the activity of antioxidant compounds from Dayak bulb ethanol extracts from Kotamobagu City. This research method is an experimental laboratory. Initially the Dayak bulb sample was extracted maceration with 96% ethanol solvent then evaporated until a thick extract was obtained. As a parameter, the DPPH method (1,1-diphenyl-2-picrylhydrazyl) was used to test the antioxidant activity of the samples at concentrations of 50, 60, 70, 80 and 90 mg / L and as a comparison standard used Vitamin C with concentrations of 2, 4, 6, 8 and 10 mg / L. The results obtained showed antioxidant activity in Dayak bulb ethanol extracts with IC50 values of 41.46 mg / L and on vitamin C IC50 values of 1.04 mg / L. Based on these results it can be concluded that the onion bulb ethanol extract has very strong antioxidant activity. Keywords: Dayak Onion bulbs, Activity, Antioxidant, DPPH  ABSTRAK Tanaman bawang Dayak (Eleutherine americana Merr.) atau biasa disebut bawang hutan merupakan tanaman khas Kalimantan Tengah yang sudah dipergunakan masyarakat lokal sebagai obat berbagai jenis penyakit. Penelitian ini bertujuan untuk mengetahui aktivitas senyawa antioksidan dari ekstrak etanol bulbus bawang Dayak yang berasal dari Kota Kotamobagu. Metode penelitian ini adalah eksperimental laboratorium. Awalnya sampel bulbus bawang Dayak diekstraksi maserasi dengan pelarut etanol 96% kemudian dievaporasi hingga didapatkan ekstrak kental. Sebagai parameter, digunakan metode DPPH (1,1-diphenyl-2-picrylhydrazyl) untuk pengujian aktivitas antioksidan sampel pada konsentrasi 50, 60, 70, 80 dan 90 mg/L dan sebagai standar pembanding digunakan Vitamin C dengan konsentrasi 2, 4, 6, 8 dan 10 mg/L. Hasil penelitian yang didapat menunjukkan aktivitas antioksidan pada ekstrak etanol bulbus bawang Dayak dengan nilai IC50 sebesar 41,46 mg/L dan pada vitamin C nilai IC50 sebesar 1,04 mg/L. Berdasarkan hasil tersebut dapat disimpulkan bahwa ekstrak etanol bulbus bawang Dayak memiliki aktivitas antioksidan yang sangat kuat. Kata kunci: Bulbus Bawang Dayak, Aktivitas, Antioksidan, DPPH

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