scholarly journals Studies Of Dissipation Pattern Of Cypermethrin In Tomato

2013 ◽  
Vol 25 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Nilfur Nahar ◽  
Mohammad Shoeb ◽  
M Iqbal Rouf Mamun ◽  
Sultan Ahmed ◽  
Mir Mahadi Hasan ◽  
...  
Keyword(s):  
Chemical Society ◽  
Residue Level ◽  
Tomato Plants ◽  
First Order ◽  
First Order Kinetics ◽  
Maximum Residue Level ◽  
Dissipation Pattern

Dissipation pattern of cypermethrin (Ripcord 10EC) on tomato plants sprayed at recommended and double the recommended doses followed first order kinetics. In both the doses residues were found below the maximum residue level (0.5 ppm) after one day of application. Recoveries were found to be 80.88% &77.09% spiked at 0.2 & 0.5 ppm, respectively. LOD and LOQ were found to be 0.01 and 0.06 ppm, respectively. Journal of Bangladesh Chemical Society, Vol. 25(2), 200-203, 2012 DOI: http://dx.doi.org/10.3329/jbcs.v25i2.15087

Rate of decrease of the residual concentration of diazinon in cabbage

1980 ◽  
Vol 20 (105) ◽  
pp. 504
Author(s):  
JR Hargreaves ◽  
KJ Melksham
Keyword(s):  
Initial Period ◽  
Residue Level ◽  
Spray Application ◽  
Rapid Decay ◽  
Residual Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Maximum Residue Level

Analysis of diazinon residues in cabbages up to 14 days after the final spray application, showed an initial period of rapid decay followed by a period of slower decay, which approximates to first order kinetics. The Australian maximum residue level of 0.7 mg kg-1 diazinon for the whole cabbage was reached in 2-3 days in summer and 7-8 days in winter. The recommended Australia 14-day withholding period, combined with marketing of hearts alone, conformed to Japanese marketing requirements of 0.1 mg kg-1.

Residue analysis of fosthiazate in cucumber and soil by QuEChERS and GC-MS

2014 ◽  
Vol 68 (10) ◽  
Author(s):  
Min Wu ◽  
Jiye Hu
Keyword(s):  
Solid Phase ◽  
Residue Analysis ◽  
Field Trials ◽  
Residue Level ◽  
Gas Chromatography Mass Spectrometry ◽  
Dispersive Solid Phase Extraction ◽  
First Order ◽  
First Order Kinetics ◽  
Maximum Residue Level ◽  
Relative Standard

AbstractA convenient method was developed for the determination and validation of fosthiazate in cucumber and soil. The procedure is based on liquid partitioning with acetonitrile followed by dispersive solid phase extraction as the clean-up step, after which samples were analysed by gas chromatography-mass spectrometry (GC-MS). The average recoveries ranged from 91.2 % to 99.0 % with relative standard deviations (RSDs) of less than 6.05 %, at three fortification levels (0.02 mg kg−1, 0.1 mg kg−1, 0.5 mg kg−1) in cucumber and soil, and the limits of quantification (LOQs) for fosthiazate were all established at 0.02 mg kg−1. The proposed method was applied successfully to analyses of the dissipation and residue of fosthiazate in field trials. The dissipation rate of fosthiazate was described using pseudo-first-order kinetics with a half-life of 4.33 days and 4.08 days in soil in Beijing and Shandong, respectively. In the terminal residue experiment, fosthiazate residues in cucumber and soil were clearly below the maximum residue level (MRL, 0.2 mg kg−1) set in China.

scholarly journals Dissipation Behavior of Three Pesticides in Prickly Pear (Opuntia ficus-indica (L.) Mill.) Pads in Morelos, Mexico

2019 ◽  
Vol 16 (16) ◽  
pp. 2922 ◽  
Author(s):  
Irene Iliana Ramírez-Bustos ◽  
Hugo Saldarriaga-Noreña ◽  
Ernesto Fernández-Herrera ◽  
Porfirio Juárez-López ◽  
Iran Alia-Tejacal ◽  
...  
Keyword(s):  
Life Time ◽  
Commercial Production ◽  
Residue Level ◽  
Prickly Pear ◽  
Order Kinetic ◽  
Opuntia Ficus Indica ◽  
First Order ◽  
Maximum Residue Level ◽  
Concentration Levels ◽  
Order Kinetic Equation

The dissipation of three field-applied pesticides (chlorothalonil, chlorpyrifos, and malathion), on cultivated prickly pear (Opuntia ficus-indica (L.) Mill.) pads was studied. The extraction of pesticides was carried out using the European quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction technique and detection was carried out using tandem liquid chromatography with mass spectrometry. At harvest, 15 days after application, pesticide dissipation was below the level of detectability. Dissipation curves for prickly pear pads fit to a first-order kinetic equation. Two initial concentration levels were used for each pesticide. The approximate dissipation time for all pesticides studied was similar (10 days) and the half-life time was around six days. Final concentrations for the three pesticides were below the reference maximum residue level (MRL) (0.01 mg/kg), which suggests that these products can be applied safely in the commercial production of prickly pear pads at the established concentrations.

PREDICTION OF THE PERSISTENCE OF THE TRIAZINE HERBICIDES ATRAZINE, CYANAZINE, AND METRIBUZIN IN REGINA HEAVY CLAY

1989 ◽  
Vol 69 (3) ◽  
pp. 587-595 ◽  
Author(s):  
A. E. SMITH ◽  
A. WALKER
Keyword(s):  
Reasonable Agreement ◽  
Clay Soil ◽  
Laboratory Data ◽  
Growing Season ◽  
First Order ◽  
First Order Kinetics ◽  
Heavy Clay ◽  
Dissipation Pattern ◽  
Residue Levels ◽  
Good Agreement

The persistence of the herbicides cyanazine, metribuzin, and atrazine was studied at different controlled temperature and moisture contents in Regina Heavy Clay soil. Degradation of the herbicides approximated first-order kinetics at temperatures in the range 5–30 °C and at moistures of above 20%. The breakdown of cyanazine was faster than metribuzin, which, in turn, was more rapid than atrazine. The breakdown of the three herbicides under field conditions, following June applications of 1.0 kg ha−1, was measured. Over 90% of the applied cyanazine had dissipated within 56 d, while the metribuzin and atrazine were more persistent, with approximately 30% of the initial treatment remaining at the end of the growing season. In all cases, there was no leaching of the chemicals below 10 cm. The laboratory data were used in conjunction with meteorological records in a computer program to simulate the dissipation pattern for the herbicides. There was good agreement between the observed and predicted residue levels for cyanazine, and a reasonable agreement for atrazine. For metribuzin, the model underestimated the rate of loss. Key words: Herbicides, atrazine, cyanazine, metribuzin, predicted field persistence

scholarly journals Residue and dissipation dynamic of spinetoram insecticide in pear fruits

2021 ◽  
Vol 57 (No. 4) ◽  
pp. 236-332
Author(s):  
Dragana Sunjka ◽  
Sanja D. Lazić ◽  
Slavica M. Vuković ◽  
Aleksandra S. Alavanja ◽  
Đura J. Nađ ◽  
...  
Keyword(s):  
Half Life ◽  
Resistance Management ◽  
Quechers Method ◽  
Important Place ◽  
First Order ◽  
Cacopsylla Pyri ◽  
First Order Kinetics ◽  
Pear Orchard ◽  
Dissipation Pattern ◽  
Set Up

Cacopsylla pyri (Linnaeus, 1758) is the most significant and widespread pear pest. It attacks the pear only, causing direct and indirect damages. This study was conducted in order to evaluate the efficacy of insecticide spinetoram in the control of C. pyri. The experiment was set up according to EPPO methods, at the locality Kula (Republic of Serbia) in a pear orchard (Williams variety). Spinetoram (250 g/kg a.i., WG) was foliar applied in the amount of 0.3 kg/ha, during overlapping pest generations, when pear was on BBCH 75 scale. The efficacy was evaluated through the number of larvae aged L<sub>1</sub>–L<sub>3</sub> and L<sub>4</sub>–L<sub>5</sub>. Spinetoram has shown satisfying efficacy, especially in the control of L<sub>1</sub>–L<sub>3</sub> larvae (81.6%). In a dissipation study, spinetoram residues in pear fruits were determined using QuEChERS method followed by HPLC-DAD. The method was validated to fulfill SANTE/12682/2019 criteria. Three days after the application, spinetoram residues in pear fruits were below the MRL (0.2 mg/kg). The results have shown that spinetoram dissipation pattern followed the first-order kinetics (R<sup>2 </sup>= 0.979) with a half-life of 2.17 days, in pear fruits. This study suggests that spinetoram could be safely used in pear, and it could take an important place in insecticide resistance management.

Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
Author(s):  
Xin Tong ◽  
Jiao Li ◽  
Jun Ma ◽  
Xiaoquan Chen ◽  
Wenhao Shen
Keyword(s):  
Degradation Rate ◽  
Southern China ◽  
Catalytic Degradation ◽  
Pulp And Paper ◽  
Gaseous Pollutants ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH &lt; 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

Biodegradation rates of aromatic contaminants in biofilm reactors

1995 ◽  
Vol 31 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Jean-Pierre Arcangeli ◽  
Erik Arvin
Keyword(s):  
Aromatic Hydrocarbons ◽  
Competitive Inhibition ◽  
Removal Rate ◽  
First Order ◽  
Biofilm Reactors ◽  
First Order Kinetics ◽  
Reducing Conditions ◽  
Low Concentrations ◽  
Degradation Rates ◽  
Order Surface

This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols, chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic compounds was typically controlled by first order kinetics. The first-order surface removal rate constants were surprisingly similar, ranging from 2 to 4 m/d. It appears that NSO-compounds inhibit the degradation of aromatic hydrocarbons, even at very low concentrations of NSO-compounds. Under nitrate-reducing conditions, toluene was easily biodegraded. The xylenes and ethylbenzene were degraded cometabolically if toluene was used as a primary carbon source; their removal was influenced by competitive inhibition with toluene. These interaction phenomena are discussed in this paper and a kinetic model taking into account cometabolism and competitive inhibition is proposed.

In-vitro Kinetic Hydrolysis Study of Metronidazole Derivatives with Carvacrol and Eugenol Using Validated RP-HPLC Method

2020 ◽  
Vol 16 ◽  
Author(s):  
M. Alarjah
Keyword(s):  
Half Life ◽  
Hplc Method ◽  
Hydrolysis Rate ◽  
First Order ◽  
First Order Kinetics ◽  
Rp Hplc ◽  
Pharmacokinetic Properties ◽  
Pseudo First Order ◽  
Kinetic Hydrolysis

Background: Prodrugs principle is widely used to improve the pharmacological and pharmacokinetic properties of some active drugs. Much effort was made to develop metronidazole prodrugs to enhance antibacterial activity and or to improve pharmacokinetic properties of the molecule or to lower the adverse effects of metronidazole. Objective: In this work, the pharmacokinetic properties of some of monoterpenes and eugenol pro metronidazole molecules that were developed earlier were evaluated in-vitro. The kinetic hydrolysis rate constants and half-life time estimation of the new metronidazole derivatives were calculated using the validated RP-HPLC method. Method: Chromatographic analysis was done using Zorbbax Eclipse eXtra Dense Bonding (XDB)-C18 column of dimensions (250 mm, 4.6 mm, 5 μm), at ambient column temperature. The mobile phase was a mixture of sodium dihydrogen phosphate buffer of pH 4.5 and methanol in gradient elution, at 1ml/min flow rate. The method was fully validated according to the International Council for Harmonization (ICH) guidelines. The hydrolysis process carried out in an acidic buffer pH 1.2 and in an alkaline buffer pH 7.4 in a thermostatic bath at 37ºC. Results: The results followed pseudo-first-order kinetics. All metronidazole prodrugs were stable in the acidic pH, while they were hydrolysed in the alkaline buffer within a few hours (6-8 hr). The rate constant and half-life values were calculated, and their values were found to be 0.082- 0.117 hr-1 and 5.9- 8.5 hr., respectively. Conclusion: The developed method was accurate, sensitive, and selective for the prodrugs. For most of the prodrugs, the hydrolysis followed pseudo-first-order kinetics; the method might be utilised to conduct an in-vivo study for the metronidazole derivatives with monoterpenes and eugenol.

Decomposition of 4,4'-(Diazoamino)-bis(5-methoxy-2-methylbenezenesulfonic Acid) in Solutions ofFD&C Red No. 40

1984 ◽  
Vol 67 (4) ◽  
pp. 844-845
Author(s):  
Naomi Richfield-Fratz
Keyword(s):  
Liquid Chromatography ◽  
Aqueous Solutions ◽  
Borate Buffer ◽  
Sodium Borate ◽  
First Order ◽  
First Order Kinetics ◽  
Color Additive ◽  
Sodium Borate Buffer

Abstract 4,4'-(Diazoamino)-bis(5-methoxy-2-methylbenzenesuIfonic acid), when present as a reaction by-product in FD&C Red No. 40, is shown to decompose rapidly in aqueous solutions of the color additive. The decomposition is halted by the addition of sodium borate buffer. Quantitationly liquid chromatography shows that decomposition is nonlinear with time and follows approximate first order kinetics.

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