DETERMINATION OF SOME HIGHLY POLAR RESTICIDES IN AGRICULTURE PRODUCTS USING TANDEM MASS SPECTROMETRY
Ekramy Mohamed Abdel Aziz Halawa;
Abstract
Ethephon the plant growth regulator and the herbicide glyphosate are commonly used in large scale in Egypt and have a high potential risk. Unfortunately, the residues of the two compounds can't be determined easily by the commonly used multi residue methods due to their high polarity and acidic characters. So the rapid and accurate methods of analysis for each of ethephon and glyphosate residues in agricultural products are needed to detect such compounds in 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:
1) Develop and validate suitable methods for analysis of ethephon and glyphosate residues.
2) Detect ethephon residues in grape samples collected from three governorates namely El-Behaira, El-Giza and Alexandria.
3) Monitor glyphosate residues in different samples and different commodities collected from Alexandria.
The obtained results could be summarized as follows:
I. Developing and validating a reliable LC-MS/MS MRM method for ethephon and glyphosate analysis:
1) Developing a reliable LC-MS/MS MRM method for ethephon analysis indicated that the most sensitive transition of ethephon are obtained by removing HCl and phosphoric group; The mass parameters of those selected transitions were: selecting the mass of parent ions was 143 and 145 dalton, selecting the mass of daughter ions was 79 and 107 dalton, decloustring potential (-25 and -30), exit potential (-6,-7,-9 and -11) and entrance potential (-10).
2) The proper HPLC conditions for ethephon analysis method were: flow rate (0.5 ml/min), time at 0 and 2 minute with 40% eluent A + 60% eluent B, time at 6 minute with 5% eluent A + 95% eluent B, time at 6.1 and 10 minute with 40% eluent A + 60% eluent B.
3) The mass parameters of final developed MRM method for glyphosate analysis were: selecting the mass of parent ions was 168 dalton, selecting the mass of daughter ions was 63, 81, 124 and 149 dalton, decloustring potential (-100, -130 and -135), exit potential (-7,-9,-13 and -15) and entrance potential (-10).
4) The proper HPLC conditions for glyphosate analysis method were: flow rate (0.5 ml/min), time at 0 minute with 100% eluent A + 0% eluent B and time at 12 minute with 5% eluent A + 95% eluent B, time at 12.1 and 16 minute with 100% eluent A + 0% eluent B.
5) Recovery for analysis of ethephon using the developed method indicated average rate of recoveries ranged 76- 96% with standard deviation ranged 1.86-9.47% on grape, 83-101% withstandard deviation ranged 2.16-12.24% on tomatoes and 96-116% with standard deviation ranged 1.29-8.50% on lentils.
6) Recovery for analysis of glyphosate using the developed method indicated average rate of recoveries ranged 97- 105% with standard deviation ranged 5-15% on grape, 99-105% with standard deviation ranged 5-10% on tomatoes and 96-103% with standard deviation ranged 8-20% on lentils.
7) Both of the studied methods for ethephon and glyphosate have LOD equal to 0.004 mg/Kg.
8) The two studied methods can determine lower concentrations of ethephon and glyphosate, which equal to0.01 mg/Kg for all studied matrices.
9) The mean value of repeatability for real contaminated grape sample for ethephon was 0.088 mg/kg ± 0.0015mg/kg, whereas it was 0.06 mg/kg ± 0.009 mg/kgfor real glyphosate contaminated dry mint sample.
10) The uncertainty due to bias found to be 3.2%, the combined uncertainty equal 16.7% and the expanded uncertainty equal 33%.
II. Detecting ethephon in grape samples collected from different governorates:
1) About 87% of the collected grape samples from El-Behaira governorate were contaminated by ethephon compound (77% are positive below MRL and 10% are positive above MRL).
2) Analysis of ethephon in collected grape samples from Alexandria governorate showed that about 97% contaminated by ethephon compound and 20% of them are positive above MRL.
3) Collected grape samples from El-Giza governorate showed that about 97% contaminated by ethephon compound and 23% of them are positive above MRL.
III. Monitoring glyphosate residues in different samples and different commodities collected from Alexandria.
Analysis of glyphosate residues in different collected samples from Alexandria showed that about 64% were contaminated by the glyphosate compound and 4% of them exceed the MRL. The obtained results show that the uncontrolled usage of ethephon and glyphosate leads to highly contaminated agriculture product, so that, the application of ethephon and glyphosate should be controlled by the upper hand with the coordination of certified laboratories, which can determine the residues of those compounds.In the future we wish to analyze a large numbers of these difficult compounds (which cannot be detected with multi residue method), and try to collect more than one compound of them in one method.
1) Develop and validate suitable methods for analysis of ethephon and glyphosate residues.
2) Detect ethephon residues in grape samples collected from three governorates namely El-Behaira, El-Giza and Alexandria.
3) Monitor glyphosate residues in different samples and different commodities collected from Alexandria.
The obtained results could be summarized as follows:
I. Developing and validating a reliable LC-MS/MS MRM method for ethephon and glyphosate analysis:
1) Developing a reliable LC-MS/MS MRM method for ethephon analysis indicated that the most sensitive transition of ethephon are obtained by removing HCl and phosphoric group; The mass parameters of those selected transitions were: selecting the mass of parent ions was 143 and 145 dalton, selecting the mass of daughter ions was 79 and 107 dalton, decloustring potential (-25 and -30), exit potential (-6,-7,-9 and -11) and entrance potential (-10).
2) The proper HPLC conditions for ethephon analysis method were: flow rate (0.5 ml/min), time at 0 and 2 minute with 40% eluent A + 60% eluent B, time at 6 minute with 5% eluent A + 95% eluent B, time at 6.1 and 10 minute with 40% eluent A + 60% eluent B.
3) The mass parameters of final developed MRM method for glyphosate analysis were: selecting the mass of parent ions was 168 dalton, selecting the mass of daughter ions was 63, 81, 124 and 149 dalton, decloustring potential (-100, -130 and -135), exit potential (-7,-9,-13 and -15) and entrance potential (-10).
4) The proper HPLC conditions for glyphosate analysis method were: flow rate (0.5 ml/min), time at 0 minute with 100% eluent A + 0% eluent B and time at 12 minute with 5% eluent A + 95% eluent B, time at 12.1 and 16 minute with 100% eluent A + 0% eluent B.
5) Recovery for analysis of ethephon using the developed method indicated average rate of recoveries ranged 76- 96% with standard deviation ranged 1.86-9.47% on grape, 83-101% withstandard deviation ranged 2.16-12.24% on tomatoes and 96-116% with standard deviation ranged 1.29-8.50% on lentils.
6) Recovery for analysis of glyphosate using the developed method indicated average rate of recoveries ranged 97- 105% with standard deviation ranged 5-15% on grape, 99-105% with standard deviation ranged 5-10% on tomatoes and 96-103% with standard deviation ranged 8-20% on lentils.
7) Both of the studied methods for ethephon and glyphosate have LOD equal to 0.004 mg/Kg.
8) The two studied methods can determine lower concentrations of ethephon and glyphosate, which equal to0.01 mg/Kg for all studied matrices.
9) The mean value of repeatability for real contaminated grape sample for ethephon was 0.088 mg/kg ± 0.0015mg/kg, whereas it was 0.06 mg/kg ± 0.009 mg/kgfor real glyphosate contaminated dry mint sample.
10) The uncertainty due to bias found to be 3.2%, the combined uncertainty equal 16.7% and the expanded uncertainty equal 33%.
II. Detecting ethephon in grape samples collected from different governorates:
1) About 87% of the collected grape samples from El-Behaira governorate were contaminated by ethephon compound (77% are positive below MRL and 10% are positive above MRL).
2) Analysis of ethephon in collected grape samples from Alexandria governorate showed that about 97% contaminated by ethephon compound and 20% of them are positive above MRL.
3) Collected grape samples from El-Giza governorate showed that about 97% contaminated by ethephon compound and 23% of them are positive above MRL.
III. Monitoring glyphosate residues in different samples and different commodities collected from Alexandria.
Analysis of glyphosate residues in different collected samples from Alexandria showed that about 64% were contaminated by the glyphosate compound and 4% of them exceed the MRL. The obtained results show that the uncontrolled usage of ethephon and glyphosate leads to highly contaminated agriculture product, so that, the application of ethephon and glyphosate should be controlled by the upper hand with the coordination of certified laboratories, which can determine the residues of those compounds.In the future we wish to analyze a large numbers of these difficult compounds (which cannot be detected with multi residue method), and try to collect more than one compound of them in one method.
Other data
| Title | DETERMINATION OF SOME HIGHLY POLAR RESTICIDES IN AGRICULTURE PRODUCTS USING TANDEM MASS SPECTROMETRY | Other Titles | الكشف عن بعض المبيدات عالية القطبية في المنتجات الزراعية باستخدام المطياف الكتلي المتتالي | Authors | Ekramy Mohamed Abdel Aziz Halawa | Issue Date | 2016 |
Recommend this item
Similar Items from Core Recommender Database
Items in Ain Shams Scholar are protected by copyright, with all rights reserved, unless otherwise indicated.