الفهرس 
ABSTRACTOnly 14 pages are availabe for public view
 |  | from | 118 |  |  |
| | | from | 118 | | |
Abstract
Acidic herbicides are one of pesticide group used to protect plant and increase crop productivity by killing weeds. In the present study, the acidic herbicides are 2,4- dichloro-phenoxyacetic acid (2,4-D), bentazone, bromoxynil, fluazifop, fluroxypyr, imazethapyr, ioxynil and triclopyr. In Egypt, acidic herbicides are commercially distributed in different formulas and the national product of many tons of strawberries and frozen vegetables including green beans harvest were exported to different countries, making them two of the top ten commodities exported agricultural products in Egypt. Unfortunately, the residues of acidic herbicides determined easily using the quick, easy, cheap, effective, rugged and safe (QuEChERS) method. Therefore, a rapid and accurate method for the analysis of acidic herbicides residues in strawberry and green beans is needed in order monitor the handled foods in local markets and to prevent the rejection cases when exported due to high levels of the residues. Considering the previous background, the present work aimed to develop, optimize, evaluate and validate such method. The developed method complies with the national and international MRLs of acidic herbicides in strawberry and green beans.
CHAPTER IV SUMMARY
[79]
The obtained results could be summarized as follows:
1) A reversed phase liquid chromatography method for the determination of acidic herbicides was developed. The chromatographic separation is done under a temperature of 40°C with 25 μL injection volume. Acidic herbicides are separated using gradient elution of 10% 50 mM ammonium acetate in deionized water with 0.1% formic acid as eluent A and methanol as eluent B at 0.3 mL/min flow rate on a ZORBAX Eclipse Plus C18 column.
2) MS/MS detection was executed using electrospray ionization in the negative ion mode with the multiple reaction monitoring (MRM) mode. Different sample preparation parameters have been tested and optimized. The final conditions involve the usage of 10 mL acetonitrile on 10 g of sample. Phase separation was achieved by shaking the extract with magnesium sulfate and sodium chloride. The pH was adjusted by using citrate buffer.
3) The procedure was validated on strawberry and green beans in accordance with the method validation criteria stated in the document SANTE/11945/2015.
CHAPTER IV SUMMARY
[80]
The precision and trueness of the method were determined from recovery experiments on five replicates of spiked blank strawberry and green beans samples at 0.01, 0.05 and 0.1 mg/kg. The range of the obtained recoveries was from 81 to 113% and their RSD% was less than 16% with correlation coefficient of more than 0.99 at the LOQ 0.01 μg/ml.
4) The proposed assay was successfully applied for the analysis of the studied acidic herbicides residues in two PT samples. This wide scope assay protocol is applicable for monitoring acidic herbicides residues in fruits and vegetables by national regulatory authorities and accredited labs; that should help to ensure safety of such widely used products