scholarly journals SORPTION OF INDAZIFLAM IN BRAZILIAN SOILS WITH DIFFERENT pH VALUES

2021 ◽  
Vol 34 (3) ◽  
pp. 494-504
Author(s):  
VALDINEI ARAÚJO GONÇALVES ◽  
LINO ROBERTO FERREIRA ◽  
MATHEUS FERREIRA FRANÇA TEIXEIRA ◽  
FRANCISCO CLÁUDIO LOPES DE FREITAS ◽  
LEONARDO D’ANTONINO
Keyword(s):  
High Performance ◽  
Superficial Layer ◽  
Weed Seed ◽  
Sorption Coefficient ◽  
Agronomic Efficiency ◽  
Freundlich Isotherms ◽  
Ph Values ◽  
Brazilian Soils ◽  
Bioassay Technique ◽  
Points Of View

ABSTRACT Pre-emergence herbicides, such as indaziflam, have agronomic efficiency when available in the soil solution, mainly in the superficial layer (0-10 cm), the region with the highest concentration of weed seed bank. However, information about the sorption of indaziflam in Brazilian soils still is scarce, since most studies available in the literature were conducted in soils of temperate regions. The objective of this study was to estimate the sorption of indaziflam using high-performance liquid chromatography (HPLC) and bioassay in a Latossolo Vermelho-Amarelo (Oxisol) and in a Cambissolo (Inceptisol), at pH values of 5.1 and 6.1. In the biossay, Sorghum bicolor was used as an indicator plant. Quantitative indaziflam data were obtained by HPLC, and the sorption and desorption coefficients were determined in the soils using Freundlich isotherms. Increasing the pH of the two soils from 5.1 to 6.1 resulted in reductions of C50 and sorption coefficient values. Desorption, a parameter estimated only by HPLC, showed an inverse behavior to that of sorption, that is, the lowest desorption was observed in the condition of highest sorption. It is concluded that the increase in pH of the studied soils reduces indaziflam sorption, influencing the recommendations of this herbicide, from both the agronomic and the environmental points of view. When the goal is to verify the presence or absence of indaziflam in the studied soils, the bioassay technique has satisfactory efficiency. Chromatographic assay is necessary when quantifying the concentration of this herbicide in the soil.

scholarly journals SORÇÃO DO HERBICIDA 2,4-D EM SOLOS BRASILEIROS

2003 ◽  
Vol 13 ◽  
Author(s):  
CLAUDIO A. SPADOTTO ◽  
MARCUS B. MATALLO ◽  
MARCO ANTONIO F. GOMES
Keyword(s):  
Organic Carbon ◽  
High Performance ◽  
Ph Dependence ◽  
Soil Samples ◽  
Organic Carbon Content ◽  
Sorption Coefficient ◽  
Brazilian Soils ◽  
Effects Of Ph ◽  
Acidic Pesticides ◽  
Acid Compound

Neste trabalho procurou-se gerar e discutir dados sobre sorção de pesticidas ácidos em solos brasileiros, considerando sua dependência do pH. Amostras de solos foram coletadas em diferentes regiões do Brasil e suas propriedades determinadas (% de argila, % de CO e pH). Valores do coeficiente de sorção do herbicida 2,4-D foram determinados em laboratório usando teste em equilíbrio padrão e cromatografia a líquido de alta eficiência (CLAE). O coeficiente de sorção (Kd) foi estimado e o coeficiente de sorção normalizado pela fração de carbono orgânico do solo (Koc) calculado para cada solo. Os resultados de Koc variaram entre 21,3 e 306,5 mL/g, sendo que dados de Koc encontrados na literatura internacional estão entre 20 e 60 mL/g. Observou-se tendência de aumento dos valores de Kd em solos com maiores teores de carbono orgânico. No entanto, houve grande variação nos valores de Koc entre solos da mesma classe. Adicionalmente, os efeitos do pH na sorção do 2,4-D foram estudados em Latossolo. Os valores de Kd e Koc diminuíram com o aumento do pH. A sorção do 2,4-D, como composto ácido, é principalmente determinada pela sua dissociação. Entretanto, a dissociação do 2,4-D pode não ser suficiente para explicar a variação em Kd (ou Koc) em função do pH. Parece que a sorção das formas aniônicas de pesticidas ácidos tem sido superestimada e o efeito da dissociação da matéria orgânica, com mudanças no pH do solo, tem sido subestimada. SORPTION OF 2,4-D HERBICIDES IN BRAZILIAN SOILS Abstract This work aimed to generate and discuss data on acid pesticides sorption in Brazilian soils, taking into account the pH dependence. Soil samples were collected in different regions of Brazil and their properties were determined (% argila, % CO and pH. Sorption coefficient of 2,4-D were measured by means of a standard batch equilibrium method and high performance liquid chromatography (HPLC) analysis. The sorption coefficient (Kd) was estimated, and the organic carbon normalized sorption coefficient (Koc) was calculated for each soil. The Koc results are between 21.3 and 306.5 mL/g, while the Koc values from international literature are in the 20 to 60 mL/g range. The Koc values tend to increase in soils with large organic carbon content. However, great Koc values variation occurred among soils in the same class. Additionally, the effects of pH in 2,4-D sorption were studied in a Brazilian Oxisol. The Kd and Koc values decreased with pH increasing. Sorption of 2,4-D, as an acid compound, is mainly driven by its dissociation. However 2,4-D dissociation is not enough to explain the variation in Kd (or Koc) as a function of pH. In general, anionic-form sorption of acidic pesticides has been overvalued; on the other hand, the overall effect of organic matter dissociation owing to pH changes has been overlooked.

HPLC Analysis of Oxytetracycline Residues in Honey

1986 ◽  
Vol 49 (5) ◽  
pp. 383-388 ◽  
Author(s):  
PETER SPORNS ◽  
SUET KWAN ◽  
LAWRENCE A. ROTH
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Aqueous Solutions ◽  
High Performance ◽  
Hplc Analysis ◽  
Extraction Procedure ◽  
Hplc Method ◽  
Limits Of Detection ◽  
Ph Values ◽  
Double Extraction

Oxytetracycline (OTC), also known commercially as Terramycin, was determined to be more stable in honey than in buffered aqueous solutions at similar pH values and temperatures. A rapid high performance liquid chromatography (HPLC) method was developed to detect and quantitate OTC using a 1:1 dilution (wt/wt) of honey samples in water. Using 355 nm as the wavelength of detection, amounts as low as 0.5 μg/ml could be detected in the above solution. The limits of detection were lowered considerably by a double extraction procedure.

scholarly journals Review: Sensors for Biosignal/Health Monitoring in Electronic Skin

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2478
Author(s):  
Hyeon Seok Oh ◽  
Chung Hyeon Lee ◽  
Na Kyoung Kim ◽  
Taechang An ◽  
Geon Hwee Kim
Keyword(s):  
High Performance ◽  
Active Component ◽  
Tactile Sensor ◽  
Wearable Devices ◽  
Advanced Technology ◽  
Electronic Skin ◽  
Points Of View ◽  
External Stimuli ◽  
Flexible Component

Skin is the largest sensory organ and receives information from external stimuli. Human body signals have been monitored using wearable devices, which are gradually being replaced by electronic skin (E-skin). We assessed the basic technologies from two points of view: sensing mechanism and material. Firstly, E-skins were fabricated using a tactile sensor. Secondly, E-skin sensors were composed of an active component performing actual functions and a flexible component that served as a substrate. Based on the above fabrication processes, the technologies that need more development were introduced. All of these techniques, which achieve high performance in different ways, are covered briefly in this paper. We expect that patients’ quality of life can be improved by the application of E-skin devices, which represent an applied advanced technology for real-time bio- and health signal monitoring. The advanced E-skins are convenient and suitable to be applied in the fields of medicine, military and environmental monitoring.

Chlorsulfuron Adsorption and Degradation in Soil

Weed Science ◽  
1985 ◽  
Vol 33 (4) ◽  
pp. 558-563 ◽  
Author(s):  
Kausalya Thirunarayanan ◽  
Robert L. Zimdahl ◽  
Darryl E. Smika
Keyword(s):  
Moisture Content ◽  
Half Life ◽  
Inverse Relationship ◽  
Degradation Rate ◽  
Field Capacity ◽  
Freundlich Isotherms ◽  
Ph Values ◽  
Degradation In Soil

Adsorption of chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino] carbonyl] benzenesulfonamide} on four soils having different pH values (6.2 to 8.1) was low. Log/log Freundlich isotherms for all soils at 8 and 30 C were linear, the extent of adsorption being greater at 8 than at 30 C. There was an inverse relationship between pH and degradation rate with a half-life of 88.5 days at pH 6.2 and 144 days at pH 8.1 at 20 C. Rapid disappearance was noted during the first 15 days after application. With decreasing moisture and temperature, chlorsulfuron degraded more slowly. The half-life ranged from 229 days at 10 C and moisture content of 75% field capacity to 62.5 days at 40 C and 75% field capacity at pH 7.7.

scholarly journals BIODEGRADAÇÃO DE GLIFOSATO EM DOIS SOLOS BRASILEIROS

2003 ◽  
Vol 13 ◽  
Author(s):  
ADEMIR SÉRGIO FERREIRA DE ARAÚJO ◽  
REGINA TERESA ROSIM MONTEIRO ◽  
ROSÂNGELA BLOTA ABAKERLI ◽  
LOURDES SILVESTRE DE SOUZA
Keyword(s):  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Soil Microorganisms ◽  
Soil Samples ◽  
Co2 Evolution ◽  
Herbicide Application ◽  
Main Metabolite ◽  
Aminomethylphosphonic Acid ◽  
Brazilian Soils ◽  
Type 3

Avaliou-se a biodegradação de Glifosato em amostras de dois solos brasileiros, ambos com e sem histórico de uso prévio do herbicida. Aplicou-se o Glifosato em 75 g de cada amostra de solo (três repetições) na dosagem recomendada para condição de campo (2,16 kg i.a./ha). A biodegradação foi avaliada monitorando-se a liberação do CO2 pelos microrganismos no período de 32 dias. Durante esse período foram quantificados os resíduos de Glifosato e seu principal metabólito por meio de extração, seguida de análise por Cromatografia a Líquido de Alta Eficiência. Os resultados mostraram que o Glifosato foi degradado pelos microrganismos do solo, com formação de seu metabólito ácido aminometilfosfônico (AMPA). A degradação mostrouse ligeiramente superior em Argissolo que em Latossolo. BIODEGRADATION OF GLYPHOSATE IN TWO BRAZILIAN SOILS Abstract It was evaluated the Glyphosate biodegradation in two Brazilian soil samples, both with and without report of previous herbicide application. Samples of 75 g of each soil type (3 replicates) were used and Glyphosate was applied in the recommended dose for field condition (2.16 kg a.i./ha). The assessment of biodegradation was done using the CO2 evolution during a 32 days period. During this period the Glyphosate residues, and its main metabolite were quantified, after extraction and analysis by high performance liquid chromatography. The results showed that Glyphosate was degraded by the soil microorganisms, with formation of its metabolite, the aminomethylphosphonic acid (AMPA). The degradation was faster in the Hapludult than in Hapludox soil.

KOH-based porous carbon from date palm seed: preparation, characterization, and application to phenol adsorption

2014 ◽  
Vol 70 (10) ◽  
pp. 1633-1640 ◽  
Author(s):  
K. Suresh Kumar Reddy ◽  
Pravin Kannan ◽  
Ahmed Al Shoaibi ◽  
C. Srinivasakannan
Keyword(s):  
Porous Carbon ◽  
High Performance ◽  
Date Palm ◽  
Low Cost ◽  
Inert Atmosphere ◽  
Average Pore ◽  
Activation Temperature ◽  
Freundlich Isotherms ◽  
Layer Adsorption ◽  
Seed Biomass

The date palm seed being one of the major forms of biomass produced from the date industry in UAE, its potential to be an appropriate precursor for the preparation of porous carbon utilizing KOH as an activating agent is assessed in the present work. The porous carbon is prepared at an activation temperature of 600 °C, impregnation ratio of 2, and activation duration of 1 hour, in an inert atmosphere using a conventional horizontal furnace. The resultant porous carbon has a Brunauer–Emmett–Teller surface area of 892 m2/g, pore volume of 0.45 cm3/g, and an average pore diameter of 1.97 nm. This porous carbon was used for adsorption studies at different initial concentrations (100–400 mg/l) and temperatures (30–50 °C). The adsorption isotherm parameters for the Langmuir and Freundlich models were determined using experimental adsorption data and it was found that both Langmuir and Freundlich isotherms described well the adsorption behavior of phenol on porous carbon. The mono layer adsorption capacity was observed to be 333 mg/g, which is highest for the reported date pam seed biomass-based porous carbon. From the data obtained, it was concluded that the removal of phenol from aqueous solution by porous carbon prepared from data palm seed is a low-cost process with an extremely high performance.

scholarly journals Determination of diclofenac residue in swine tissue following intramuscular administration

2005 ◽  
Vol 59 (5-6) ◽  
pp. 603-609
Author(s):  
Zorica Pejcic ◽  
Milanka Jezdimirovic ◽  
Milena Pokrajac
Keyword(s):  
High Performance Liquid Chromatography ◽  
Injection Site ◽  
High Performance ◽  
Diclofenac Sodium ◽  
The Other ◽  
Local Inflammation ◽  
Analytic Procedure ◽  
Ph Values ◽  
Swine Tissue

Diclofenac residue (DF) in swine tissue (liver, kidney, muscle, injection site) were examined using the method of High Performance Liquid Chromatography (HPLC) 15h, 72h,and 120h after i.m. administration of an individual therapeutic dose of diclofenac-sodium. At 15h after administration, the highest concentration of DF was found in the kidney (0.614 mg/kg), while a concentration about two times lower was found in the liver (0.316 mg/kg). At the injection site, the DF concentration was 0.432 mg/kg, while DF remained in a very low concentration (0.052 mg/kg) in the muscle outside the injection site, which was the lowest concentration in comparison with all the other examined tissues. At 72h after administration, DF was present in all examined tissues, but its concentrations were lower than the level that could be determined using the analytic procedure. Traces of the administered medicine disappeared after the waiting period of 120h in all tissues, except for the injection site. The longer presence of the medicine at the injection site could be a consequence of local inflammation, or irritation, that could cause a reduction in pH values of the area around the injection site, thus leading to slower dissolving and a longer presence of the DF at the injection site.

Long-term stability of ready-to-use 1-mg/mL midazolam solution

2020 ◽  
Vol 77 (9) ◽  
pp. 681-689
Author(s):  
Sixtine Gilliot ◽  
Morgane Masse ◽  
Frédéric Feutry ◽  
Christine Barthélémy ◽  
Bertrand Décaudin ◽  
...  
Keyword(s):  
High Performance ◽  
Detection Method ◽  
Degradation Products ◽  
Storage Conditions ◽  
Target Concentration ◽  
Long Term Stability ◽  
Ph Values ◽  
Particle Contamination ◽  
The Stability

Abstract Purpose Midazolam is a benzodiazepine derivative commonly used in intensive care units to control sedation. Its use requires dilution of a 5-mg/mL commercial solution to a target concentration of 1 mg/mL. A study was conducted to evaluate the stability of diluted ready-to-use 1-mg/mL midazolam solutions over 365 days when stored in cyclic olefin copolymer vials or polypropylene syringes. Methods A specific stability-indicating high-performance liquid chromatography coupled with UV detection method was developed for midazolam hydrochloride and validated for selectivity, linearity, sensitivity, precision, and accuracy. Three storage conditions were tested: –20°C ± 5°C, 5°C ± 3°C, and 25°C ± 2°C at 60% ± 5% relative humidity. Half of the vials were stored upside down to test for the absence of interaction between midazolam and the stopper. Particle contamination, sterility, and pH were assessed. Results The limit of stability was set at 90% of the initial concentration. After 1 year’s storage at –20°C and 5°C, concentrations remained superior to 90% under all storage conditions. At 25°C, stability was maintained up to day 90 in syringes (mean [SD], 92.71% [1.43%]) and to day 180 in upright and upside-down vials (92.12% [0.15%] and 91.57% [0.15%], respectively). No degradation products were apparent, no variations in pH values were detected, and containers retained their sterility and conformity with regard to any specific contamination during the study. Conclusion The evaluated 1-mg/mL midazolam solution was stable over a 1-year period when stored at a refrigerated (5°C) or frozen (–20°C) temperature in both vials and syringes; with storage at 25°C, the stability duration was lower. The preparation of ready-to-use midazolam solutions by a hospital pharmacy is compatible with clinical practice and could help to decrease risks inherent in dilution in care units.

scholarly journals Sorption-Desorption Behavior of Imazethapyr and Imazapic on Six Brazilian Soils

2018 ◽  
Vol 36 ◽  
Author(s):  
M.I.C. MARINHO ◽  
W.M. SOUZA ◽  
M.F. CABRAL ◽  
M.D. CASTRO NETO ◽  
M.E.L.R. QUEIROZ ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Soil Ph ◽  
High Performance ◽  
Agricultural Soils ◽  
Iron Oxalate ◽  
Brazilian Soils ◽  
Imidazolinone Herbicides ◽  
Main Factor

ABSTRACT: The characterization of sorption-desorption for imazethapyr and imazapic in six agricultural soils was performed to assess the availability of these herbicides in pollution processes. In this pursuit, the batch equilibrium method and high-performance liquid chromatography were used. The magnitude of Kf values ranging from 0.38 to 2.52 mg1-n kg-1 Ln for imazethapyr and 0.43 to 2.72 mg1-n kg-1 Ln for imazapic indicate weak sorption in the evaluated soils. Soil pH (5.1 to 6.1) and iron oxalate affect sorption-desorption of both herbicides but the type and percentage of clay can be the main factor affecting these two processes. A high desorption percentage (>70%) was found in Regosol, Dystric Plinthosol, Ferralsol (for both herbicides), and Dystric Gleysol (only imazapic) soils, which implies in leaching risks of these imidazolinone herbicides into groundwater. Lower desorption (<50%) was found in Cambisol and Alisol (for both herbicides), and (~50%) in Dystric Gleysol (only imazethapyr) soils, indicating that these herbicides could potentially injure the sensitive crops grown in rotation.

Activation mechanism and effectiveness in reusing sludge from water purification

2000 ◽  
Vol 42 (3-4) ◽  
pp. 273-281
Author(s):  
K. Ebie ◽  
J.-H. Lee ◽  
T.-H. Yoon
Keyword(s):  
Activation Mechanism ◽  
High Concentration ◽  
Recycling Process ◽  
Ph Variation ◽  
Ph Values ◽  
Sludge Recycling ◽  
Influent Water ◽  
Points Of View ◽  
Sedimentation Basins ◽  
Ph Range

The sludge extracted from chemical sedimentation basins shows a high concentration of aluminium which was added in the rapid mix tank. Therefore, the sludge volume after activation treatment with hydrochloric acid can be reused in order to coagulate turbid matter and humic substances in influent water. This study has focussed on examining the effectiveness of this sludge recycling process. HPLC with a RI detector was used to determine the molecular weight (M. W.) of PAC in the pH range of 3.0∼5.0. Results indicated that PAC was composed of two kinds of aluminium complexes at pH 3, having a M. W. of about 11,200 and 6,400. The M. W. of PAC in the pH variation and after the repetition of the activation treatment was also determined. Moreover, the abilities of PAC activated under the variable pH values to coagulate simulated natural surface water containing kaolin or humic acid were evaluated though jar-tests. When the pH in activated PAC was set at under 4, the coagulability of PAC did not deteriorate even if the activation treatment was repeated three times. In conclusion, the effectiveness of this process in practical use has been made clear from three points of view: the ph, the M. W., and the coagulability of PAC.

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