Determination of the activation energy of the relaxation time of the composite cellulose: synthetic ester with a high water content

2019 ◽  
Author(s):  
Konrad Kierczynski
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Synthetic Ester

scholarly journals Determination of Selected Priority Pesticides in High Water Fruits and Vegetables by Modified QuEChERS and GC-ECD with GC-MS/MS Confirmation

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 417 ◽  
Author(s):  
Maciej Tankiewicz
Keyword(s):  
Water Content ◽  
Fruits And Vegetables ◽  
High Water ◽  
International Agency ◽  
High Water Content ◽  
Vegetable Crops ◽  
Fruit And Vegetable ◽  
Quechers Method ◽  
Relative Standard

A modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method coupled to gas chromatography with electron capture detector (GC-ECD) was developed for simultaneous determination of selected electronegative pesticides in fruits and vegetables with high water content. The chosen compounds are commonly detected in fruit and vegetable crops, and some of their metabolites have even been found in human urine. In addition, some of them are known or suspected carcinogens according to the International Agency for Research of Cancer. Extraction and clean up parameters were optimized, thus the original QuEChERS method was modified to decrease solvent usage, in accordance with ‘green chemistry’ principles. The proposed methodology was validated in terms of selectivity, specificity, linearity, precision and accuracy. The obtained limits of detection (LODs) for all investigated pesticides ranged from 5.6 µg·kg−1 to 15 µg·kg−1 and limits of quantification (LOQs) from 17 µg·kg−1 to 45 µg·kg−1. The obtained data demonstrated the good reproducibility and stability of the procedure in the tested concentration range up to 10 mg·kg−1, with relative standard deviations (RSDs) lower than 10%. Recoveries for spiked pear samples at LOQ level for each pesticide were from 90% to 107% with RSDs lower than 9.6%. The suitability of the developed procedure was tested on various fruit and vegetable samples available on the market at different seasons. The proposed methodology is applicable for detection and monitoring of selected pesticides not only in fruits and vegetables with high water content, but also in samples containing large amounts of pigments and dyes.

scholarly journals Optimalization of multiresidue method for the determination of pesticide residues in fruits

2021 ◽  
Vol 61 (3) ◽  
pp. 221-238
Keyword(s):  
Water Content ◽  
Pesticide Residues ◽  
High Water ◽  
High Water Content ◽  
Detector Response ◽  
Wide Range ◽  
Comprehensive Determination ◽  
Selective Detectors ◽  
Active Substances

The main aim of this study was to optimize the QuEChERS methodology for the comprehensive determination of pesticide residues using a simple and inexpensive gas chromatography equipped with selective detectors working simultaneously (GC-ECD/NPD). The method was validated in accordance with the SANTE/11945/2015 guidelines. Representative fruit matrices were chosen from the commodities group with high water content (apples), and with high acidity and high water content (strawberry) for a 160 compounds in the range of 0.005−0.02 mg/kg. The accuracy of the method was as required (recovery: 70–120%, precision: below 20%) for 135 active substances in apples samples and 137 in strawberries samples. The main advantages of the methodology include: good detector response linearity (R2 above 0.995), low limits of detection (0.005 mg/kg for more than 20 compounds, 0.01 mg/kg for about 120 compounds), possibility of simultaneous determination of a wide range of compounds (including some “difficult” ones) without use of a single residue methods. The simultaneous use of two selective detectors allows to obtain more data during a single dose of the sample and confirmation of the result for most compounds, which allows to prevent false positives ones.

scholarly journals Principles of Irrigation Management for Vegetables

2021 ◽  
Author(s):  
Selda Ors ◽  
Ustun Sahin ◽  
Melek Ekinci ◽  
Metin Turan ◽  
Ertan Yildirim
Keyword(s):  
Water Content ◽  
Irrigation System ◽  
Irrigation Management ◽  
High Water ◽  
Irrigated Agriculture ◽  
High Water Content ◽  
Yield And Quality ◽  
Vegetable Soil ◽  
Management Concept

Vegetables have a very high percentage of water content. Some of the vegetables, such as cucumber, tomato, lettuce, zucchini, and celery contain over ninety-five percent of water. As a result of the high-water content in the cells, they are extremely vulnerable plants to water stress and drought conditions. Their yield and quality are affected rapidly when subjected to drought. Therefore, irrigation is essential to the production of most vegetables in order to have an adequate yield with high quality. However, over-irrigating can inhibit germination and root development, decrease the vegetable quality and post-harvest life of the crop. Determination of suitable irrigation systems and scheduling to apply proper amount of water at the correct time is crucial for achieving the optimum benefits from irrigation. This determination requires understanding of the water demand of the vegetable, soil characteristics, and climate factors. All these factors have major impact for the success and sustainability of any vegetable irrigation. This section contains fundamentals of water requirements on different vegetables and summarizes important issues related to soil, water, and vegetable growth relations together with irrigation management concept by evaluating the challenging issues on the selection of proper irrigation system, suitable irrigation timing, and other parameters to increase vegetable yield in an irrigated agriculture.

QuEChERS Approach for the Determination of Biopesticides in Organic and Nonorganic Vegetables and Fruits by Ultra-Performance Liquid Chromatography/Tandem Mass Spectrometry

2014 ◽  
Vol 97 (4) ◽  
pp. 1027-1033 ◽  
Author(s):  
Roberto Romero-González ◽  
Patricia Plaza-Bolaños ◽  
Rocío I Limón-Garduza ◽  
José L Martínez-Vidal ◽  
Antonia Garrido Frenich
Keyword(s):  
Water Content ◽  
Organic Farming ◽  
High Water ◽  
Ultra Performance Liquid Chromatography ◽  
High Water Content ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Food Commodities ◽  
Vegetables And Fruits

Abstract A method for the determination of 14 biopesticides and piperonyl butoxide (PBO), often applied in organic farming, in vegetables and fruits has been developed. Extraction was performed using the Quick, Easy, Cheap, Effective, Rugged, and Safe method, and the determination was carried out by ultra-performance LC/MS/MS in 9 min. Several different food commodities were evaluated as representative matrixes, namely, cucumber, tomato, pepper (high water content), and strawberry and orange (high acid and water content). Biopesticides were quantified using matrix-matched calibration, and the optimized method was validated at three concentration levels, i.e., 10, 50, and 100 μg/kg, for all the compounds, yielding recoveries in the range 70–112%, 71–112%, and 70–109%, respectively, with RSDs <28%. LOQs were <3 μg/kg for all biopesticides. The validated procedure was applied to the analysis of vegetables and fruits, including products from organic farming; PBO was detected in one sample at 8 μg/kg.

A multi-residue method for the determination of 90 pesticides in matrices with a high water content by LC–MS/MS without clean-up

2012 ◽  
Vol 29 (4) ◽  
pp. 665-678 ◽  
Author(s):  
Fernando Diniz Madureira ◽  
Fabiano Aurélio da Silva Oliveira ◽  
Wesley Robert de Souza ◽  
Ana Paula Pontelo ◽  
Mauro Lúcio Gonçalves de Oliveira ◽  
...  
Keyword(s):  
Water Content ◽  
High Water ◽  
High Water Content

Hydrogels as Antibacterial Biomaterials

2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Water Content ◽  
Oxygen Permeability ◽  
Structural Diversity ◽  
High Water ◽  
Clinical Applications ◽  
High Water Content ◽  
Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

Microwave-Induced Thermoacoustic Imaging for Embedded Explosives Detection in High-Water Content Medium

2019 ◽  
Vol 67 (7) ◽  
pp. 4803-4810 ◽  
Author(s):  
Xiong Wang ◽  
Tao Qin ◽  
Yexian Qin ◽  
Ahmed H. Abdelrahman ◽  
Russell S. Witte ◽  
...  
Keyword(s):  
Water Content ◽  
High Water ◽  
Explosives Detection ◽  
High Water Content ◽  
Thermoacoustic Imaging
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