Determination of the Concentration of Organic Compounds using an Electrochemical Test System

2019 ◽  
pp. 117-123
Author(s):  
N.V. Lukovtseva ◽  
V.A. Semenova ◽  
V.P. Lukovtsev ◽  
K.N. Bobov ◽  
E.M. Petrenko
Keyword(s):  
Organic Matter ◽  
Organic Compounds ◽  
Experimental Studies ◽  
Test System ◽  
Organic Substances ◽  
Vector Representation ◽  
Electrochemical Test ◽  
Specific Test ◽  
Form Complex ◽  
The Difference

The research paper looks at the possibility of using an electrochemical test system to determine the concentration of organic compounds. The experiments were based on the fact that each class of organic substances required a specific test system. Since we were interested in sulfurcontaining organic compounds, the electrochemical test system was a solution containing cations of zinc, gallium, and copper. These metals can form complex compounds with sulfur-containing organic substances. When inserted into such a test system, organic substances of this class significantly alter its electrochemical behavior, which is reflected in stripping voltammograms. The experimental procedure and software made it possible to obtain the required number of parameters, which enabled a multisensory analysis on a single working (indicative) electrode. The stripping voltammograms recorded before and after addition of organic matter to the electrochemical test system were digitized; then one voltammogram (recorded when the test system contained no admixtures) was deducted from the other one (recorded when organic matter was added to the test system). The resulting difference curve was divided into segments; experiments showed that the number of segments should not exceed 20 or 30. These digitized curved sections were integrated in order to obtain a set of informative parameters, which can be viewed as a set of vectors, i.e., a multi-dimensional vector representation of each analyte. To visualize the results of the electroanalytical study, we represent the multidimensional image of organic substances of various concentrations as a number of vectors arranged in a circlel; the number of vectors corresponds to the number of sections of the difference curves in each experiment. The results show that the length of the vectors characterizing the difference curves decreases as the concentration of the analyzed organic matter decreases. In the limit, the curve visualizing organic matter with zero concentration takes the form of a circle, which indicates that there are no deviations from the stripping voltammogram of the electrochemical test system. Therefore, it can be concluded that the electrochemical test system can be certainly used for determining the concentration of organic compounds, producing quite reliable estimated results. This conclusion is confirmed by comparing the vector representation of analytes with the vector representations of organic substances of different concentrations, which constitute the database containing the results of experimental studies. Such a comparison is given in the form of a histogram reflecting the degree of proximity of the vector representation of the analyzed organic matter to substances from the database based on an estimate of Euclidean distances between the corresponding multidimensional vectors.

scholarly journals Electrochemical Test System for Analysis of Sulfur-Containing Organic Substances

2019 ◽  
pp. 88-95 ◽  
Author(s):  
V.P. Lukovtsev ◽  
N.V. Lukovtseva ◽  
V.A. Semenova
Keyword(s):  
Organic Compounds ◽  
Test System ◽  
Oil Refining ◽  
Organic Substances ◽  
Electrochemical Test ◽  
Form Complex ◽  
Experimental Data Processing ◽  
Study Results ◽  
Vector Representations ◽  
Sulfur Containing

The paper discusses selection of a set of metals for an electrochemical test system used for the detection of sulfur-containing organic substances. Analytical studies of organic sulfur compounds are very important since these compounds are widely used in medicine, biology, oil refining industry, etc. Quantitative determination and identification of sulfur-containing substances is essential for solving environmental problems. The electrochemical test system for analysis of organic substances is a solution containing a set of cations of various metals that have the ability to form complex compounds with analytes. Thereby, a single electrode can be used to carry out electrochemical multisensory analysis because metal cations play the role of sensors. Thus, there is no need to use a set of several working (indicator) electrodes, the number of which determines the number of informative parameters. Since sets of metals for test systems may slightly differ from each other, we need to select an optimal set for a specific problem. According to the study results, a set of metals for sulfur-containing organic substances consists of zinc, gallium and copper. The test system composed of these metals gives reliable results of electroanalytical determination of organic compounds of this class. The expediency of using such a test system is confirmed by comparative estimation of the Euclidean distances between the vector representations of the analytes and sulfur-containing organic compounds presented in the previously created database. Software for experimental data processing, visualization, and comparative analysis of the vector representations and the database components is developed.

Evaluation of wastewater characterization methods

2005 ◽  
Vol 52 (10-11) ◽  
pp. 61-68 ◽  
Author(s):  
E.-H. Choi ◽  
B. Klapwijk ◽  
A. Mels ◽  
H. Brouwer
Keyword(s):  
Organic Matter ◽  
Organic Compounds ◽  
Nitrate Concentration ◽  
Characterization Methods ◽  
Biochemical Characteristics ◽  
Organic Components ◽  
N Removal ◽  
Curve Fit ◽  
The Difference

Wastewater contains various organic components with different physical and biochemical characteristics. ASM No. 1 distinguishes two categories of biodegradable organic matter in wastewater, rapidly and slowly biodegradable. In general there are two methods for wastewater characterization: based on filtration in combination with a long-term BOD test or based on a respirogram. By comparing both approaches, we showed that in wastewater three categories of organic compounds with different biodegradation rates can be distinguished. These categories are referred to as readily biodegradable, rapidly hydrolysable and slowly hydrolysable organic matter. The total biodegradable COD can be found from a long-term BOD-test combined with a curve-fit and the readily biodegradable and rapidly hydrolysable from a respirogram. The slowly hydrolysable is the difference between total biodegradable COD and the sum of readily biodegradable and rapidly hydrolysable COD. Simulation with characterization based on filtration for a pre-anoxic reactor with a certain N-removal compared with the N-removal of the same plant with wastewater according to the modified characterization shows different results of each wastewater, especially with regard to the effluent nitrate concentration.

scholarly journals Pengaruh Koagulan Biji Asam Jawa (Tamarindus indica) Terhadap Efisiensi Penurunan Zat Organik Pada Air Gambut

2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Vina Lestari Riyandini ◽  
Muhammad Iqbal
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Compounds ◽  
Quality Standard ◽  
Clean Water ◽  
Organic Substances ◽  
Tamarindus Indica ◽  
Natural Coagulants ◽  
The Village ◽  
Dose Variation

Organic substances in peat water cause smell, have a brown color and taste, in addition to that it can interfere the processing process by forming carcinogenic trihalomethane which is produced from the reaction between organic compounds and chlorine. Peat water used in this study came from the village of Tuah Indrapura, Siak Regency with a concentration of organic matter of 95.2 mg/L. Based on Permenkes No. 492 of 2010 the concentration of organic substances exceeds the quality standard, so it needs to be treated before being used as a source of clean water. Therefore, in this study, uses the coagulation method of flocculation by utilizing natural coagulants, namely tamarind seeds (Tamarindus Indica). The study was conducted using variations in the size of biokoagulan by 200 mesh, 230 mesh, and 270 mesh with a dose variation of 1 gr, 2 gr, 3 gr, 4 gr dan 5 gr. The result showed that using 270 mesh biokoagulan particle size as much as 2 grams can set aside organic matter by 64%. This allowance is not large enough because tannins only form aggregates with organic substances in the form of proteins and alkaloids.

Identification and Comparative Analysis of Alkaloids by Inversion Voltammetry Method

2019 ◽  
pp. 113-121
Author(s):  
V.A. Semenova ◽  
E.M. Petrenko
Keyword(s):  
Electronic Tongue ◽  
Small Mass ◽  
Test System ◽  
Complex Compounds ◽  
Electrochemical Test ◽  
Form Complex ◽  
New Approach ◽  
Psychotropic Substances ◽  
Detection And Identification ◽  
Inversion Voltammetry

The alkaloids concurrent detection and identification in the samples by the method of multisensory inversion voltammetry is the purpose of the work. To achieve this goal, the proposed method has been substantiated, the composition of the electrochemical test system has been optimized taking into account the specifics of the detected substances, and informative signs that characterize the presence of alkaloids in the studied sample have been found. A new approach, consisting in the use of an electrochemical multisensor test system in the form of a solution containing a set of metal ions that can form complex compounds with organic substances, has been developed and scientifically approved. The results showed that each organic substance has a different effect on the electrochemical behavior of the multisensory test system. The use of such a test system made it possible to model the principle currently defined by the term "Electronic tongue". An electronic database has been prepared according to the results of the electroanalytical studies, which made it possible to identify the detected substance by comparing it with analyzed sample. The proposed electrochemical method, which is based on multisensor inversion voltammetry, allows the detection and identification of both narcotic drugs and psychotropic substances with high confidence for a small mass of the sample.

Soil organic matter formation: Convergence and divergence of three carbon pathways: Stabilization, recycling and losses

2020 ◽  
Author(s):  
Yakov Kuzyakov ◽  
Ezekiel Bore ◽  
Michaela Dippold
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Organic Compounds ◽  
Microbial Transformation ◽  
Pentose Phosphate ◽  
Organic Substances ◽  
Microbial Utilization ◽  
Trace Back ◽  
Convergence And Divergence

<p>Microbial transformation of organic substances is a key process of soil organic matter (SOM) formation. Carbon (C) entering the soil can be transformed in three main directions: i) stabilization over long period without relevant microbial utilization, ii) recycling by microorganisms for production of new and reparation of old cells, and iii) microbial utilization for energy production leading to C losses from soil as CO<sub>2</sub>. So, individual compounds within huge diversity of the organic substances entering the soil will follow predominantly one of these directions, depending on the substance chemistry, soil properties, microbial activities and environmental conditions. Therefore, organic substances can have two general trends: i) they converge from any initially distinct compounds (e.g. in litter or rhizodeposition) to completely mixed, so that it is impossible to trace back their origin; or ii) divergence: the substances maintain their differences despite microbial transformations by SOM formation.</p><p>We proved two opposite hypotheses that convergence and divergence of the fate of organic substances depends on microbial utilization at two levels: 1) intermolecular: high recycling intensity leads to convergence, whereas stabilization leads to divergence of the C originated from various organic compounds, and 2) incorporation of C from various molecule positions into microbial metabolic cycles define the C fate at intramolecular level. We tested the first hypothesis based on own and literature data to the fate of polymeric substances: sugars, proteins, lipids and lignin. The second hypothesis was tested by the C atoms from various positions of pentoses and hexoses by position-specific <sup>13</sup>C and <sup>14</sup>C labeling.</p><p>The polymeric substances as well as monomers from the same chemical group clearly converge to three groups stabilization, recycling and losses. Carboxylic acids will be nearly completely mineralized and are lost from soil. The fate and functions organic compounds depend mainly on microbial recycling. Proteins, amino acids and sugars - key components of microbial biomass - are intensively recycled and e.g. proteins remain relatively long in soil.</p><p>For the intramolecular differences, we traced the fate of position-specific <sup>13</sup>C labeled glucose and ribose under field conditions for 800 days. Both sugars were simultaneously metabolized via glycolysis and pentose phosphate pathway. The similarity between position-specific <sup>13</sup>C recovery in microbial biomass and soil reflected high contribution of microbial necromass to SOM. The mean residence time of uniformly labeled <sup>13</sup>C ribose in the soil was 3 times longer than that of glucose. Consequently, ribose and glucose were incorporated into different cellular components, defining their long-term fate in soil. The convergence of glucose C positions in soil and microbial biomass revealed that recycling dominated glucose transformation. In contrast, divergence of ribose C positions in soil revealed that intact ribose-derived cell components are reused or preserved in SOM.</p><p>Thus, convergence vs. divergence distinguished the two general trends explaining the long persistence of C at inter- and intra-molecular levels: microbial recycling leads to convergence, whereas slow decomposition and preservation define the divergence of C pathways in soil.</p>

Characteristics of fouling due to clay-organic substances in potable water treatment by ultrafiltration

1996 ◽  
Vol 34 (9) ◽  
pp. 157-164 ◽  
Author(s):  
Kim C.-H. ◽  
M. Hosomi ◽  
A. Murakami ◽  
M. Okada
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acid ◽  
Fulvic Acid ◽  
Size Distribution ◽  
Ultrafiltration Membrane ◽  
Organic Substances ◽  
Decomposition Products ◽  
Microbial Decomposition ◽  
Fouling Materials

Effects of clay on fouling due to organic substances and clay were evaluated by model fouling materials and kaolin. Model fouling materials selected were protein, polysaccharide, fulvic acid, humic acid and algogenic matter (EOM:ectracellular organic matter, microbial decomposition products) and kaolin was selected as the clay material. Polysulfone membrane (MWCO(Molecular Weight Cut-Off) 10,000, 50,000 and 200,000) was used as an ultrafiltration membrane. In particular, the flux measurement of solutions containing algogenic matter used an ultrafiltration membrane of MWCO 50,000. The flux of protein and polysaccharide with coexistence of kaolin increased in the case of the ratio of MW/MWCO being greater than one, but did not increase in the case of the MW/MWCO ratio being below one. In contrast, the flux of fulvic acid and humic acid with coextence of kaolin decreased regardless of the ratio of MW/MWCO. The addition of dispersion agent and coagulant in the organic substances and kaolin mixture solution changed the size distribution of kaolin, and resulted in a change of the flux. EOM and microbial decomposition products decreased with the increase of the fraction of organic matter having molecular weight more than MWCO of membrane. The flux of the algogenic organic matter with coexistence of kaolin decreased with the increase of the amount of kaolin. It was suggested that the decline of the flux with coexistence of kaolin was due to the change of the resistance of the kaolin cake layer corresponding to the change in kaolin size distribution with charge.

The Forming of Model Colloid System

2014 ◽  
Vol 971-973 ◽  
pp. 266-269 ◽  
Author(s):  
Denis A. Voyno ◽  
Ksenia I. Machekhina ◽  
Ludmila N. Shiyan
Keyword(s):  
Water Treatment ◽  
Zeta Potential ◽  
Electrostatic Interaction ◽  
Organic Substance ◽  
Test System ◽  
Molar Ratio ◽  
Organic Substances ◽  
Mechanism Of Formation ◽  
Iron Silicon ◽  
Colloid System

The paper reports on the creation of a model colloid test system which is similar to groundwater and it can be used as a test system in the water treatment. It is found that at the molar ratio iron/silicon/organic substance is equal to1/7/2 and two orders such as organic substances-Si-Fe and Si-organic substances-Fe, stable colloid system is formed. The mechanism of formation of iron colloid system is described by three steps. The first is the formation of the organosilicon complexes. The second is oxidation of the iron and forming of Fe (OH)3. The last is forming a sol at zeta potential is - 35 mV with electrostatic interaction.

Soil stripping and replacement for the rehabilitation of bauxite-mined land at Weipa. I. Initial changes to soil organic matter and related parameters

Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 345 ◽  
Author(s):  
G. D. Schwenke ◽  
D. R. Mulligan ◽  
L. C. Bell
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Field Experiments ◽  
Surface Soil ◽  
Soil Disturbance ◽  
Microbial Biomass C ◽  
Low Grade ◽  
Double Pass ◽  
Organic C ◽  
The Difference

At Weipa, in Queensland, Australia, sown tree and shrub species sometimes fail to establish on bauxite-mined land, possibly because surface-soil organic matter declines during soil stripping and replacement. We devised 2 field experiments to investigate the links between soil rehabilitation operations, organic matter decline, and revegetation failure. Experiment 1 compared two routinely practiced operations, dual-strip (DS) and stockpile soil, with double-pass (DP), an alternative method, and subsoil only, an occasional result of the DS operation. Other treatments included variations in stripping-time, ripping-time, fertiliser rate, and cultivation. Dilution of topsoil with subsoil, low-grade bauxite, and ironstone accounted for the 46% decline of surface-soil (0–10 cm) organic C in DS compared with pre-strip soil. In contrast, organic C in the surface-soil (0–10 cm) of DP plots (25.0 t/ha) closely resembled the pre-strip area (28.6 t/ha). However, profile (0–60 cm) organic C did not differ between DS (91.5 t/ha), DP (107 t/ha), and pre-strip soil (89.9 t/ha). Eighteen months after plots were sown with native vegetation, surface-soil (0–10 cm) organic C had declined by an average of 9% across all plots. In Experiment 2, we measured the potential for post-rehabilitation decline of organic matter in hand-stripped and replaced soil columns that simulated the DS operation. Soils were incubated in situ without organic inputs. After 1 year’s incubation, organic C had declined by up to 26% and microbial biomass C by up to 61%. The difference in organic C decline between vegetated replaced soils (Expt 1) and bare replaced soils (Expt 2) showed that organic inputs affect levels of organic matter more than soil disturbance. Where topsoil was replaced at the top of the profile (DP) and not ploughed, inputs from volunteer native grasses balanced oxidation losses and organic C levels did not decline.

scholarly journals ORGANIC CARBON DYNAMICS IN GRASSLAND SOILS. 1. BACKGROUND INFORMATION AND COMPUTER SIMULATION

1981 ◽  
Vol 61 (2) ◽  
pp. 185-201 ◽  
Author(s):  
J. A. VAN VEEN ◽  
E. A. PAUL
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Experimental Studies ◽  
Decay Rates ◽  
Background Information ◽  
Plant Residues ◽  
Decomposition Rates ◽  
Straw Decomposition ◽  
Soil Biomass ◽  
The World

The decomposition rates of 14C-labelled plant residues in different parts of the world were characterized and mathematically simulated. The easily decomposable materials, cellulose and hemicellulose, were described as being decomposed directly by the soil biomass; the lignin fraction of aboveground residues and the resistant portion of the roots entered a decomposable native soil organic matter. Here it could be decomposed by the soil biomass or react with other soil constituents in the formation of more recalcitrant soil organic matter. The transformation rates were considered to be independent of biomass size (first–order). Data from 14C plant residue incorporation studies which yielded net decomposition rates of added materials and from carbon dating of the recalcitrant soil organic matter were transformed to gross decomposition rate constants for three soil depths. The model adequately described soil organic matter transformations under native grassland and the effect of cultivation on organic matter levels. Correction for microbial growth and moisture and temperature variations showed that the rate of wheat straw decomposition, based on a full year in the field in southern Saskatchewan, was 0.05 that under optimal laboratory conditions. The relative decay rates for plant residues during the summer months of the North American Great Plains was 0.1 times that of the laboratory. Comparison with data from other parts of the world showed an annual relative rate of 0.12 for straw decomposition in England, whereas gross decomposition rates in Nigeria were 0.5 those of laboratory rates. Both the decomposable and recalcitrant organic matter were found to be affected by the extent of physical protection within the soil. The extent of protection was simulated and compared to data from experimental studies on the persistence of 14C-labelled amino acids in soil. The extent of protection influenced the steady-state levels of soil carbon upon cultivation more than did the original decomposition rates of the plant residues.

scholarly journals Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions

2015 ◽  
Vol 15 (8) ◽  
pp. 4145-4159 ◽  
Author(s):  
A. P. Praplan ◽  
S. Schobesberger ◽  
F. Bianchi ◽  
M. P. Rissanen ◽  
M. Ehn ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Organic Compounds ◽  
Atmospheric Pressure ◽  
Molar Mass ◽  
Oxidation Products ◽  
Neutral Species ◽  
Mass Spectrometers ◽  
Comprehensive Picture ◽  
The Difference ◽  
Chemical Ionisation

Abstract. This study presents the difference between oxidised organic compounds formed by α-pinene oxidation under various conditions in the CLOUD environmental chamber: (1) pure ozonolysis (in the presence of hydrogen as hydroxyl radical (OH) scavenger) and (2) OH oxidation (initiated by nitrous acid (HONO) photolysis by ultraviolet light) in the absence of ozone. We discuss results from three Atmospheric Pressure interface Time-of-Flight (APi-TOF) mass spectrometers measuring simultaneously the composition of naturally charged as well as neutral species (via chemical ionisation with nitrate). Natural chemical ionisation takes place in the CLOUD chamber and organic oxidised compounds form clusters with nitrate, bisulfate, bisulfate/sulfuric acid clusters, ammonium, and dimethylaminium, or get protonated. The results from this study show that this process is selective for various oxidised organic compounds with low molar mass and ions, so that in order to obtain a comprehensive picture of the elemental composition of oxidation products and their clustering behaviour, several instruments must be used. We compare oxidation products containing 10 and 20 carbon atoms and show that highly oxidised organic compounds are formed in the early stages of the oxidation.

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