scholarly journals Volatile and Non-Volatile Organic Compounds Stimulate Oviposition by Aphidophagous Predators

Insects ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 683
Author(s):  
Eric W. Riddick
Keyword(s):  
Molecular Weight ◽  
Volatile Organic Compounds ◽  
Vapor Pressure ◽  
Organic Compounds ◽  
Egg Production ◽  
United States Department ◽  
Oviposition Stimulants ◽  
Molecular Weights ◽  
Production Ratio ◽  
Volatile Organic

Introduction: Evidence that volatile organic compounds (VOCs) and non-VOCs stimulate oviposition by aphidophagous predators is scattered throughout the literature. The objectives of this review are to (1) compile records indicating that VOCs and non-VOCs are responsible for oviposition stimulation, (2) calculate an egg production ratio (EPR) for stimulated predators, and (3) determine if EPR is correlated with vapor pressure and molecular weight of active compounds. Methods: The USDA (United States Department of Agriculture), National Agricultural Library, online digital catalog system was used to retrieve abstracts, then the full text of manuscripts on oviposition stimulants for predators. Oviposition-stimulating VOCs and non-VOCS were tabulated with molecular weights and vapor pressure estimates. EPRs were calculated for stimulated coccinellids, syrphids, and chrysopids. Results: Both VOCs and non-VOCs stimulated oviposition behavior by coccinellids and syrphids, but not chrysopids. EPR was greatest for syrphids. Two VOCs, (E)-β-farnesene and 3-methyl-2-butenal, stimulated very high EPR values by the syrphid Episyrphusbalteatus. Regardless of predator taxa, EPR was negatively and positively correlated with molecular weight and vapor pressure, respectively. Conclusions: Syrphids (rather than coccinellids or chrysopids) produce more eggs in response to VOCs. Organic compounds with low-to-moderate molecular weights and moderate-to-high vapor pressures might be most effective oviposition stimulants for aphidophagous predators.

scholarly journals Storage Stability of Volatile Organic Compounds from Petrochemical Plant of China in Different Sample Bags

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Fenglei Han ◽  
Huangrong Zhong ◽  
Ting Li ◽  
Yongqiang Wang ◽  
Fang Liu
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Recovery Rate ◽  
Storage Stability ◽  
Petrochemical Plant ◽  
Pure Nitrogen ◽  
Molecular Weights ◽  
Volatile Organic ◽  
Protective Gas ◽  
The Impact

According to the emission characteristics of volatile organic compounds (VOCs) in the petrochemical plants of China, the storage stability of VOCs for two different bags, polyester aluminum (PEA) and polyvinyl fluoride (PVF), was investigated in this study by comparing the adsorption of gas samples. A series of experiments were carried out to study the impact of different factors of sampling in the petrochemical industry. The results showed that the C2∼C3 substances can be adsorbed by the Tedlar bag, and after being refilled with pure nitrogen, the VOCs adsorbed previously by the bag material can be released. The aromatic hydrocarbon VOCs with larger molecular weight had a relatively lower recovery rate than the smaller molecular weights. And the average recovery of PEA airbags was significantly better than that of PVF airbags for storing stationary VOCs in the refinery of China. More kinds of substances can be detected in the airbags that had been added with helium protective gas, and it had a higher recovery rate for both kinds of simple bags after 24 hours of storage time, which indicated that the airbags without protective gas had adsorbed these substances.

scholarly journals Quantitative structure-property relationship studies for the prediction of the vapor pressure of volatile organic compounds

2019 ◽  
Vol 84 (12) ◽  
pp. 1405-1414
Author(s):  
Mounia Zine ◽  
Amel Bouakkadia ◽  
Leila Lourici ◽  
Djelloul Messadi
Keyword(s):  
Regression Analysis ◽  
Volatile Organic Compounds ◽  
Linear Regression ◽  
Vapor Pressure ◽  
Multiple Linear Regression ◽  
Organic Compounds ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Test Set ◽  
Volatile Organic

A theoretical model (QSPR) using multiple linear regression analysis for predicting the vapor pressure (pv) of volatile organic compounds (VOCs) has been developed. A series of 51 compounds were analyzed by multiple linear regression analysis. First, the data set was separated arbitrarily into a training set (39 chemicals) and a test set (12 chemicals) for statistical external validation. A four-dimensional model was developed using as independent variables theoretical descriptors derived from Dragon software when applying the GA (genetic algorithm)?VSS (variable subset selection) procedure. The obtained model was used to predict the vapor pressure of the test set compounds, and an agreement between experimental and predicted values was verified. This model, with high statistical significance (R2 = 0.9090, Q2 LOO = 0.8748, Q2 ext = 0.8307, s = 0.24), could be used adequately for the prediction and description of the log pv value of other VOCs. The applicability domain of MLR model was investigated using a William?s plot to detect outliers and outsides compounds.

Fingerprinting of volatile organic compounds for quick assessment of vigour status of seeds

2020 ◽  
Vol 30 (2) ◽  
pp. 112-121 ◽  
Author(s):  
R. Umarani ◽  
M. Bhaskaran ◽  
C. Vanitha ◽  
M. Tilak
Keyword(s):  
Molecular Weight ◽  
Volatile Organic Compounds ◽  
Moisture Content ◽  
Organic Compounds ◽  
Low Molecular Weight ◽  
Organic Substances ◽  
Seed Deterioration ◽  
Volatile Organic ◽  
Quick Assessment ◽  
Storage Reserves

AbstractSeed is a fertilized mature ovule, which possesses an embryonic plant. When the dry, mature seeds are subjected to imbibition, they release a wide range of organic substances, which include low molecular weight carbonyl compounds (gases and volatiles) and water-soluble organic substances (enzymes and polysaccharides). The volatile organic compounds (VOCs) are molecules of low molecular weight (300 g mol−1) and high vapour pressure (0.01 kPa at 20°C) and include diverse chemical compounds. The nature and emission kinetics of volatiles produced from seeds vary, depending on the moisture content of the seeds. Orthodox seeds stored at ‘low seed moisture content’ undergo seed deterioration, predominantly due to lipid peroxidation, initiated by autoxidation or enzymatic oxidation of unsaturated or polyunsaturated fatty acids. This peroxidation leads to emission of volatile compounds. The quantity of VOCs emitted is positively correlated with the advancement of seed deterioration. With respect to the seed germination process, exposure of seeds to ‘high moisture conditions’ leads to increased respiration, triggers glycolysis and mobilization of storage reserves, resulting in the emission of volatile metabolic products. The quantity of VOCs emitted on commencement of metabolic activity in germinating seeds depends on (1) vigour status and (2) amount of storage reserves. Since it has been established that there is a significant difference between high and low vigour seeds with respect to quantity and profile of VOCs emitted, there is great potential for utilizing the VOC profile to obtain a quick and reproducible test of vigour status of crop seeds. In order to harness the VOC profile for quick assessment of vigour status of seeds, research has to be taken up to develop standard protocols for fingerprinting of VOCs for the purpose of seed vigour assessment and to fix the standard volatile biomarker(s) specific to crop and vigour status of seeds.

Potassium fluoride as a selective moisture trapping agent for SPE-TD-GC-FID determination of volatile organic compounds in air

2015 ◽  
Vol 7 (2) ◽  
pp. 458-465 ◽  
Author(s):  
O. V. Rodinkov ◽  
G. A. Zhuravlyova ◽  
E. A. Vaskova ◽  
I. A. Platonov
Keyword(s):  
Molecular Weight ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Potassium Fluoride ◽  
Low Molecular Weight ◽  
Moist Air ◽  
Volatile Organic ◽  
Trapping Agent ◽  
Adsorption Concentration

Anhydrous potassium fluoride has been proposed as a novel selective moisture trapping agent for gas chromatography to remove water vapor during adsorption concentration of low molecular weight volatile organic compounds (VOCs) from moist air.

scholarly journals THE DETERMINATION OF MOLECULAR WEIGHT

1955 ◽  
Vol 33 (5) ◽  
pp. 755-762 ◽  
Author(s):  
A. F. Sirianni ◽  
I. E. Puddington
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Organic Compounds ◽  
Chemical Stability ◽  
Pressure Difference ◽  
Molecular Weight Range ◽  
Vapor Pressure Difference ◽  
Static Measurement ◽  
Molecular Weights

The molecular weights of organic compounds of known constitution have been determined with satisfactory accuracy, using milligram quantities of materials, by a static measurement of the vapor pressure difference between pure solvents and solutions of the compounds. The method may be used over a considerable temperature range. The suitability of solvents is governed by their chemical stability and vapor pressure. Results obtained using compounds in the molecular weight range of 600–1000 are reported.

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