scholarly journals Fate of Preharvest-Sprayed Dicofol in Date Fruits: Residue Analysis by HPLC-UV

2005 ◽  
Vol 10 (1) ◽  
pp. 21 ◽  
Author(s):  
S. Al-Rehiayani ◽  
K.A. Osman
Keyword(s):  
High Performance ◽  
Fruits And Vegetables ◽  
Date Palm ◽  
Residue Analysis ◽  
Second Phase ◽  
Time Intervals ◽  
Biphasic Model ◽  
Palm Trees ◽  
Recovery Percentage ◽  
Date Fruits

The fate of pre-harvest-sprayed dicofol (DCF) on date fruits has been investigated. Date palm trees, variety Sukkari, were sprayed with DCF (18.5%, EC) at the rate of 200 ml/100 L. DCF residues in date fruits were determined at different time intervals using high performance liquid chromatography (HPLC) with UV detection at 220 nm. The method was based on extraction with ethyl acetate. The results showed that the HPLC response was linear (r2 > 0.98) for DCF in the range of 0.0 to 2 mμg. The limits of detection and quantification were 0.24 and 0.80 ppm, respectively. The method was developed by using spiked date fruits at levels of 0.25, 0.50 and 1.0 ppm. Recovery percentage was satisfactory with a range of 77.2 to 103.6% and an RSD ranging from 6.33 to 11.84%. A biphasic model was assumed in order to carry out the statistical study of the loss of DCF from date fruits. The results showed that the initial deposit of DCF on date fruits was 11.22 ppm, while the residue value decreased to 1.90 ppm seven days after spraying, which is below the tolerance limit for fruits and vegetables (2 ppm). Also, the data indicate that there was a faster rate of DCF loss in the first phase than the second one. This is clearly reflected in the t1/2 values, where the half-lives of DCF were 1.35 and 38.52 days, for the first and second phase model, respectively. The described method is rapid and sensitive, with satisfactory recoveries and reproducibility. 

UHPLC/ESI Q-Orbitrap Quantitation of 655 Pesticide Residues in Fruits and Vegetables—A Companion to an nDATA Working Flow

2020 ◽  
Vol 103 (6) ◽  
pp. 1547-1559
Author(s):  
Jian Wang ◽  
Daniel Leung ◽  
Willis Chow ◽  
Jon W Wong ◽  
James Chang
Keyword(s):  
Pesticide Residues ◽  
High Performance ◽  
Fruits And Vegetables ◽  
Residue Analysis ◽  
Resolving Power ◽  
Intermediate Precision ◽  
Monitoring Programs ◽  
Routine Monitoring ◽  
Mass Resolving Power ◽  
Chromatographic Resolution

Abstract Background Effective and expansive methods for multiresidue pesticide analysis are desired for routine monitoring programs. These methods are complex, especially when several hundred pesticides are involved. Objective Two approaches to sort data and identify isomers and isobaric ions in pesticide mixtures were evaluated to determine whether they could be differentiated by mass resolving power and/or chromatographic resolution. Method This study presents an application of ultra-high performance liquid chromatography electrospray Q-Orbitrap mass spectrometry (UHPLC/ESI Q-Orbitrap) along with QuEChERS for the quantitation of 655 pesticide residues in fruits and vegetables. Results From the developed method, 94.7% of the 655 pesticides in fruits and 93.9% of those in vegetables had recoveries between 81% and 110%; 98.3% in both fruits and vegetables had an intermediate precision of ≤20%; and 97.7% in fruits or 97.4% in vegetables showed measurement uncertainty of ≤50%. When the retention time difference (ΔtR) of two isomers was ≥0.12 min, they were chromatographically resolved. Twenty five out of 35 pairs or groups of isomers were chromatographically separated (ΔtR ≥ 0.12 min), but 14 pairs were not resolved (ΔtR < 0.12 min). There were 493 pairs of pesticides with a mass-to-charge difference of <1 Da. Only one pair of isobaric ions could not be separated by mass and chromatographic resolution. Highlights UHPLC/ESI Q-Orbitrap along with QuEChERS sample preparation offers a practical quantitative companion method to a non-target data acquisition for target analysis workflow for pesticide residue analysis in routine monitoring programs for food safety.

scholarly journals Deletion of beta-fructofuranosidase (invertase) genes is associated with sucrose content in Date Palm fruit

2019 ◽  
Author(s):  
Joel A. Malek ◽  
Sweety Mathew ◽  
Lisa Mathew ◽  
Shameem Younuskunju ◽  
Yasmin A. Mohamoud ◽  
...  
Keyword(s):  
Date Palm ◽  
Homozygous Deletion ◽  
Genomic Region ◽  
Sucrose Content ◽  
Palm Fruit ◽  
Palm Trees ◽  
Date Fruit ◽  
Invertase Gene ◽  
High Sucrose ◽  
Date Fruits

AbstractThe fruit of date palm trees are an important part of the diet for a large portion of the Middle East and North Africa. The fruit is consumed both fresh and dry and can be stored dry for extended periods of time. Date fruits vary significantly across hundreds of cultivars identified in the main regions of cultivation. Most dried date fruit are low in sucrose but high in glucose and fructose. However, high sucrose content is a distinctive feature of some date fruit and affects flavor as well as texture and water retention. To identify the genes controlling high sucrose content we analyzed date fruit metabolomics for association with genotype data from 121 date fruits. We found significant association of dried date sucrose content and a genomic region that contains 3 tandem copies of the beta-fructofuranosidase (invertase) gene in the reference Khalas genome, a low sucrose fruit. High sucrose cultivars including the popular Deglet Noor had a homozygous deletion of two of the 3 copies of the invertase gene. We show the deletion allele is derived when compared to the ancestral allele that retains the all copies of the gene in 3 other species of Phoenix. The fact that 2 of the 3 tandem invertase copies are associated with dry fruit sucrose content will assist in better understanding the distinct roles of multiple date palm invertases in plant physiology. Identification of the recessive alleles associated with end-point sucrose content in date fruit may be used in selective breeding in the future.

scholarly journals Effects of Various Quantities of Three Irrigation Water Types on Yield and Fruit Quality of ‘Succary’ Date Palm

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 796
Author(s):  
Mohamed A. Mattar ◽  
Said S. Soliman ◽  
Rashid S. Al-Obeed
Keyword(s):  
Soil Water ◽  
Fruit Quality ◽  
Irrigation Water ◽  
Deficit Irrigation ◽  
Date Palm ◽  
Saline Water ◽  
Irrigation Level ◽  
Water Types ◽  
Palm Trees

A field experiment was conducted on date palm trees (Phoenix dactylifera ‘Succary’) cultivated on sandy loam soil from 2017 to 2018. This study investigated the effects of providing water of three different qualities, namely freshwater (FR) and two saline water sources: reclaimed wastewater (RW) and well-water (WE) applied through three irrigation levels representing 50% (I50), 100% (I100), and 150% (I150) of crop evapotranspiration (ETc), on the soil water and salt distribution patterns, yield, water productivity (WP), and fruit quality of the ′Succary′ date palm. The electrical conductivity (ECw) of FR, RW, and WE were 0.18, 2.06, and 3.94 dS m−1, respectively. Results showed that WE applied by the I150 treatment had the highest soil water content, followed by RW used in the I100 irrigation level and FR with I50, whereas the soil salt content was high for WE applied in the I50 level and low for FR applied by the I150 treatment. Deficit irrigation (I50) of date palms with either RW or WE reduced date yields on average 86 kg per tree, whereas the yield increased under over-irrigation (I150) with FR to 123.25 kg per tree. High WP values were observed in the I50 treatments with FR, RW, or WE (on average 1.82, 1.68, and 1.67 kg m−3, respectively), whereas the I150 treatment with each of the three water types showed the lowest WP values. Fruit weight and size were the lowest in the full irrigation (I100) with WE, whereas the I150 treatment with RW showed the highest values. There were no significant differences in either total soluble solids (TSS) or acidity values when the irrigation level decreased from 100% to 50% ETc. Compared with both I50 and I100 treatments, reduced values of both TSS and acidity were observed in the I150 treatment when ECw decreased from 3.94 to 0.18 dS m−1,. Fruit moisture content decreased with the application of saline irrigation water (i.e., RW or WE). Total sugar and non-reducing sugar contents in fruits were found to be decreased in the combination of RW and I150, whereas the 50% ETc irrigation level caused an increment in both parameters. These results suggest that the application of deficit irrigation to date palm trees grown in arid regions, either with FR or without it, can sufficiently maximize WP and improve the quality of fruits but negatively affects yield, especially when saline water is applied. The use of saline water for irrigation may negatively affect plants because of salt accumulation in the soil in the long run.

scholarly journals Development and Application of a Novel Pluri-Residue Method to Determine Polar Pesticides in Fruits and Vegetables through Liquid Chromatography High Resolution Mass Spectrometry

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 553
Author(s):  
Lorena Manzano-Sánchez ◽  
José Antonio Martínez-Martínez ◽  
Irene Domínguez ◽  
José Luis Martínez Vidal ◽  
Antonia Garrido Frenich ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Resolution ◽  
High Performance ◽  
Fruits And Vegetables ◽  
High Resolution Mass Spectrometry ◽  
Stationary Phases ◽  
Mean Values ◽  
Polar Pesticides ◽  
Relative Standard ◽  
The Matrix

Nowadays, highly polar pesticides are not included in multiresidue methods due to their physico-chemical characteristics and therefore, specific analytical methodologies are required for their analysis. Laboratories are still looking for a pluri-residue method that encompasses the largest number of polar pesticides. The aim of this work was the simultaneous determination of ethephon, 2-hydroxyethylphosphonic acid (HEPA), fosetyl aluminum, glyphosate, aminomethylphosphonic acid (AMPA), N-acetyl-glyphosate and N-acetyl-AMPA in tomatoes, oranges, aubergines and grapes. For that purpose, an ultra high performance liquid chromatography (UHPLC) coupled to a high resolution single mass spectrometer Orbitrap-MS were used. Different stationary phases were evaluated for chromatographic separation, and among them, the stationary phase Torus DEA provided the best separation of the selected compounds. The QuPPe method was used for the extraction of the analytes, but slight modifications were needed depending on the matrix. The developed method was validated, observing matrix effect in all matrices. Intra- and inter-day precision were estimated, and relative standard deviation were lower than 19%. Recoveries were satisfactory, and mean values ranged from 70% to 110%. Limits of quantification were between 25 and 100 µg kg−1. Finally, the analytical method was applied to different fruits and vegetables (oranges, tomatoes, aubergines and grapes).

Numerical Investigations on Partial Surge Initiated Inception and Stall Evolution in a Transonic Compressor

2017 ◽  
Author(s):  
Jiaguo Hu ◽  
Tianyu Pan ◽  
Wenqian Wu ◽  
Qiushi Li ◽  
Yifang Gong
Keyword(s):  
High Performance ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Rapid Decline ◽  
Second Phase ◽  
Stall Inception ◽  
Transonic Compressor ◽  
Transient Simulations ◽  
Two Factors

The instability has been the largest barrier of the high performance axial compressor in the past decades. Stall inception, which determines the route and the characteristics of instability evolution, has been extensively focused on. A new stall inception, “partial surge”, is discovered in the recent experiments. In this paper full-annulus transient simulations are performed to study the origin of partial surge initiated inception and explain the aerodynamic mechanism. The simulations show that the stall inception firstly occurs at the stator hub region, and then transfers to the rotor tip region. The compressor finally stalled by the tip region rotating stall. The stall evolution is in accord with the experiments. The stall evolution can be divided into three phases. In the first phase, the stator corner separation gradually merged with the adjacent passages, producing an annulus stall cell at the stator hub region. In the second phase, the total pressure rise of hub region emerges rapid decline due to the fast expansion of the annulus stall cell, but the tip region maintains its pressure rise. In the third phase, a new rotating stall cell appears at the rotor tip region, leading to the onset of fast drop of the tip region pressure rise. The stall cells transfer from hub region to the tip region is caused by two factors, the blockage of the hub region which transfers more load to the tip region, and the separation fluid fluctuations in stator domain which increase the circumferential non-uniformity in the rotor domain. High load and non-uniformity at the rotor tip region induce the final rotating stall.

scholarly journals Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 878 ◽  
Author(s):  
Qing Wang ◽  
Zhen Li ◽  
Shujie Pang ◽  
Xiaona Li ◽  
Chuang Dong ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Performance ◽  
Particle Morphology ◽  
Precipitation Strengthening ◽  
Second Phase ◽  
High Entropy ◽  
Second Phase Particles ◽  
Alloy Strength ◽  
Solid Solution Matrix ◽  
The Relationship

High-performance conventional engineering materials (including Al alloys, Mg alloys, Cu alloys, stainless steels, Ni superalloys, etc.) and newly-developed high entropy alloys are all compositionally-complex alloys (CCAs). In these CCA systems, the second-phase particles are generally precipitated in their solid-solution matrix, in which the precipitates are diverse and can result in different strengthening effects. The present work aims at generalizing the precipitation behavior and precipitation strengthening in CCAs comprehensively. First of all, the morphology evolution of second-phase particles and precipitation strengthening mechanisms are introduced. Then, the precipitation behaviors in diverse CCA systems are illustrated, especially the coherent precipitation. The relationship between the particle morphology and strengthening effectiveness is discussed. It is addressed that the challenge in the future is to design the stable coherent microstructure in different solid-solution matrices, which will be the most effective approach for the enhancement of alloy strength.

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