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.

scholarly journals Effects of heat treatment and storage temperature on the use of açaí drink by nutraceutical and beverage industries

2012 ◽  
Vol 32 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Tatiane Regina Albarici ◽  
José Dalton Cruz Pessoa
Keyword(s):  
Temperature Effect ◽  
Storage Temperature ◽  
Life Time ◽  
Reaction Rate Constant ◽  
Anthocyanin Content ◽  
Order Kinetic ◽  
First Order ◽  
The Stability ◽  
And Storage ◽  
Anthocyanin Degradation

This study assesses the storage temperature effect on the anthocyanins of pasteurized and unpasteurized açaí pulp. The data was obtained using a pasteurized and lyophilized pulp (PLP) to evaluate the temperature effect (0, 25, and 40 °C). Part of non-pasteurized frozen pulp (NPP) was pasteurized (NPP-P) at 90 °C for 30 seconds; both pulps were stored at 40 °C. The anthocyanin content reduction in the drink was evaluated from the half-life time (t1/2), activation energy (Ea), temperature quotient (Q10), and the reaction rate constant (k). The t1/2 of the PLP anthocyanins stored at 40 °C was 1.8 times less than that stored at 25 °C and 15 times less than that stored at 0 °C; therefore, the higher temperatures decreased the stability of anthocyanins. The pasteurization increased the t1/2 by 6.6 times (10.14 hours for NPP and 67.28 hours for NPP-P). The anthocyanin degradation on NPP-P followed a first order kinetic, while NPP followed a second order kinetic; thus it can be said that the pasteurization process can improve the preservation of anthocyanins in the pulp.

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.

scholarly journals Effect of inoculum to substrate ratio on biogas production of sheep paunch manure

2016 ◽  
Vol 62 (No. 1) ◽  
pp. 8-14 ◽  
Author(s):  
A.A. Lawal ◽  
A.U. Dzivama ◽  
M.K. Wasinda
Keyword(s):  
Biogas Production ◽  
Coefficient Of Determination ◽  
Order Kinetic ◽  
Production Rates ◽  
Exponential Equation ◽  
First Order ◽  
Gompertz Equation ◽  
Volatile Solids ◽  
Substrate Ratio ◽  
Order Kinetic Equation

Sheep paunch manure was anaerobically digested to study the effect of inoculum to substrate ratio on biogas production rates and accumulation. Inoculum to substrate ratios of 1.37, 2.05 and 4.1 were digested in biodigesters labelled R1, R2 and <br /> R3 respectively. Results showed that inoculum to substrate ratio had a significant effect on biogas production rates and accumulation. Biogas production rates increased to peak in the order of R3 (0.30526 Nm<sup>3</sup>/kg volatile solids (VS) days), R2 (0.15308 Nm<sup>3</sup>/kg VS d) and R1 (0.11009 Nm<sup>3</sup>/kg VS d) on the 5<sup>th</sup> day. The biogas production accumulation increased from 0.57195 to 1.46784 Nm<sup>3</sup>/kg VS as the inoculum to substrate ratio increased. The result of regression showed that coefficient of determination values for the linear equation ranged from 0.707 to 0.797, while the exponential equation had higher values that ranged from 0.7718 to 0.9929 showing better simulation. The modified Gompertz equation showed better simulation of the biogas production accumulation than the first order kinetic equation due to its higher coefficient of determination values.

Degradation of 4-nitrophenol using the Fenton process

2000 ◽  
Vol 42 (3-4) ◽  
pp. 155-160 ◽  
Author(s):  
Y.-S. Ma ◽  
S.-T. Huang ◽  
J.-G. Lin
Keyword(s):  
Kinetic Equation ◽  
Nitrogen Concentration ◽  
Order Kinetic ◽  
Fenton Process ◽  
Nitrogenous Compounds ◽  
First Order ◽  
Degradation Rate Constant ◽  
Before And After ◽  
Pseudo First Order ◽  
Order Kinetic Equation

In this study, The Fenton process was applied as a pretreatment method to treat industrial wastewater containing 4-nitrophenol (4-NP). The effect of oxidant dosages on the decomposition of 4-NP and the reaction kinetics were investigated. More than 99% of 4-NP was readily decomposed when the reaction was carried out at oxidant concentrations of 5 mM H2O2 and 5 mg/L Fe2+ for 2 hours. The total nitrogenous compounds and the nitrogen gas evolved, accounted for 88% of the initial nitrogen concentration. However, the maximum DOC removal efficiency was 30.6%; and only 1/3 of 4-NP was mineralized to carbon dioxide by the Fenton process. 4-NP degradation profiles fitted well into a pseudo first-order kinetic equation; degradation rate constant (min-1) of 4-NP increased from 4.3×10-3 to 66.1×10-3 with increasing dosages of H2O2 and Fe2+. In addition, the t value was calculated for studying the significance of simulation by the t-test. It was found that the t value was greater than the value for 99% confidence. This result suggested that the 4-NP decomposition profile could be described by the pseudo first-order kinetic equation. Biodegradability of 4-NP before and after the reaction was 0.018 and 0.594, respectively.

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 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

Performance evaluation of anoxic and facultative wastewater stabilization ponds

1996 ◽  
Vol 33 (7) ◽  
pp. 141-145 ◽  
Author(s):  
Muwaffaq M. Saqqar ◽  
M. B. Pescod
Keyword(s):  
Performance Evaluation ◽  
Kinetic Equation ◽  
Simple Model ◽  
Operating Time ◽  
Order Kinetic ◽  
Sediment Depth ◽  
First Order ◽  
Maximum Value ◽  
Wastewater Stabilization Ponds ◽  
Order Kinetic Equation

The performance of anoxic and facultative ponds in Jordan was investigated for 12 months. Calculated values of the first order kinetic equation rate for CBOD removal (KCBOD) has resulted in different KCBOD's for different ponds in the same month, at the same temperature. It is evident that factors other than temperature must influence values of KCBOD. The KCBOD values determined were generally lower than those reported in the literature. The maximum value found was only 0.16 (/day). A pond was emptied after 18 months of operation and sediment was found randomly distributed over the pond area, with a depth ranging from 2 to 6 cm (averaging ≈ 4 cm). A simple model has been established to estimate sediment depth (Hs in cm) in terms of the operating time in months (t).

scholarly journals Stability of tetracycline residues in honey

2012 ◽  
Vol 77 (7) ◽  
pp. 879-886 ◽  
Author(s):  
Cara Cristina ◽  
Dumitrel Gabriela-Alina ◽  
Glevitzky Mirel ◽  
Perju Delia
Keyword(s):  
Life Time ◽  
Order Kinetic ◽  
First Order ◽  
Reaction Rate Constants ◽  
Veterinary Medicines ◽  
West Region ◽  
Tetracycline Degradation ◽  
Order Kinetic Model ◽  
Tetracycline Residues ◽  
Kinetics Of

The problem of availability of veterinary medicines to treat honeybees is discussed extensively worldwide. An uncontrolled administration of antibiotics may lead to contamination of beehive products and contributes to the problem of food safety. In this study, the kinetics of tetracycline (TC) degradation in honey was studied for samples provided by four sideline beekeepers located in the west region of Romania. The samples of honey were stored in the dark at room temperature for 30 days and subsamples were analyzed every 3 days by Elisa method. The results of the study revealed that the level of tetracycline decreases in time for all honey samples. The tetracycline degradation follows a first-order kinetic model with reaction rate constants between 1.2?10-3 - 2?10-3 days-1. The half-life time of tetracycline in monofloral honeys: acacia and lime was 251 and 232 days respectively. Tetracycline degradation in polyfloral honey was accelerated since ?1/2 of TC was 151 days.

UV Protectants for the Biopesticide Based on Photostabilization of Ecdysone

2011 ◽  
Vol 183-185 ◽  
pp. 401-405 ◽  
Author(s):  
Hua Nan Guan ◽  
De Fu Chi ◽  
Jia Yu
Keyword(s):  
Ultraviolet Light ◽  
Larvicidal Activity ◽  
Half Life ◽  
Moderate Degree ◽  
Order Kinetic ◽  
Synthetic Compounds ◽  
First Order ◽  
Glass Slides ◽  
Life Values ◽  
Order Kinetic Equation

The ultraviolet protectant (UV protectant) properties of different natural and synthetic compounds were investigated for a biopesticide based on ecdysone. This study examined the photostabilization of ecdysone when exposed to ultraviolet light in the presence of some ultraviolet protectants. Ecdysone solutions with and without UV protectants in methanol were applied onto the surface of glass slides. At particular intervals, the remaining concentration of ecdysone was analyzed by HPLC. Using first-order kinetic equation, the dissipation half-life values (DT50) for the degradation of ecdysone under ultraviolet radiation were obtained. The larvicidal activity was evaluated against the larvae of Martianus dermestoides Chevrolat. It indicated that the addition of congo red, yeast, starch and arabia gum provided moderate degree of photostabilization of ecdysone and that addition of lignin provided the best photostabilization of ecdysone, among these UV protectants studied. Toxicity of the ecdysone with UV protectants was higher to the larvae of M. dermestoides Chevrolat compared to the ecdysone alone as indicated by the lower EC50 value. The dissipation half-life values of ecdysone after irradiation under ultraviolet light and the larvicidal activity suggested that the addition of lignin (in 1:l mol ratio) can provide better photostabilization of ecdysone molecule.

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