scholarly journals Analysis of the Dissipation Behavior of Defoliants in Cotton Fiber during Field and Scouring Process Using Liquid and Gas Chromatography

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Mingbo Ma ◽  
Pirah Ayaz ◽  
Wanhui Jin ◽  
Munir Hussain ◽  
Wenlong Zhou

Defoliants carried by cotton fiber could harm production workers and consumers through respiratory and dermal exposure. This study was carried out to evaluate the dissipation behavior of four commonly used defoliants tribufos, diuron, thidiazuron, and ethephon in cotton fiber during field stage and also in cotton scouring using liquid chromatography and gas chromatography. Field trials showed that although all the defoliants dissipated fast, however, the fiber from the tribufos and ethephon applied field had considerable potential to exceed the maximum residue limit when the fiber was harvested at common intervals after application of defoliants. The defoliant residues could be removed completely from the defoliant-carrying cotton textiles during alkaline scouring. The results indicated that attention should be paid to the risk of occupational exposure to these defoliants rather than consumer exposure. Fiber harvest on the tribufos and ethephon applied fields is recommended after a 1-week delay in order to reduce the residues to an acceptable level.

2020 ◽  
Vol 5 (1) ◽  
pp. 42-47
Author(s):  
Md Sultan Ahmed ◽  
Afroza Begum ◽  
Debasish Sarker

The study was undertaken to determine the pre-harvest interval (PHI) for dimethoate and quinalphos in cauliflower, eggplant and hyacinth bean depending on Maximum Residue Limit (MRL) set by European Union. Six supervised field trials were conducted and sprayed with the recommended dose (2 ml/L of water) of each pesticide. Samples were collected at 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 days after spray (DAS). The collected samples were analyzed using Gas Chromatography (GC) with Flame Thermionized Detector (FTD) for the determination of pesticide residue. The quantities of residue were above MRL up to 9 DAS for quinalphos in cauliflower, 7 DAS in hyacinth bean, 8 DAS in eggplant; 11 DAS for dimethoate in cauliflower, 10 DAS in hyacinth bean, and 9 DAS in eggplant. At 11 DAS, no residue was detected from any of the tested samples except dimethoate in cauliflower. The determined PHI for quinalphos was 10 DAS in cauliflower, 8 DAS in hyacinth bean and 9 DAS in eggplant. In case of dimethoate it was 12 DAS in cauliflower, 11 DAS in hyacinth bean and 10 DAS in eggplant. Asian Australas. J. Biosci. Biotechnol. 2020, 5 (1), 42-47


2021 ◽  
Vol 6 (2) ◽  
pp. 60-67
Author(s):  
Md Sultan Ahmed ◽  
Mohammad Dalower Hossain Prodhan ◽  
Afroza Begum ◽  
Marina Afroze ◽  
Debasish Sarker

A study was carried out to detect and estimate the residue of cypermethrin and chlorpyrifos in brinjal, tomato and cauliflower using Gas Chromatography (GC) coupled with Electron Capture Detector (ECD) and Flame Thermionic Detector (FTD). Three supervised field trials were conducted and sprayed with the recommended dose of cypermethrin (1 ml/L of water) and chlorpyrifos (3 ml/L of water) in three vegetables by knapsack sprayer. Samples were collected at 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 days after spray (DAS). The quantity of cypermethrin residue was above EU-MRLs (Maximum Residue Limit set by European Union) up to 4 DAS with 0.538 mg/kg in cauliflower; 3 DAS with 0.508 mg/kg in brinjal and 0.695 mg/kg in tomato. The quantity decreased down 0.328-0.019 mg/kg in cauliflower (4-9 DAS); 0.098-0.012 mg/kg (4-7 DAS) in brinjal and 0.458-0.022 mg/kg (4-7 DAS) in tomato which were below EU-MRLs (0.5 mg/kg). The quantity of chlorpyrifos residue was above EU-MRLs up to 9 DAS with 0.012 mg/kg in cauliflower but in brinjal and tomato, the detected quantities were above EU-MRLs up to 7 DAS with 0.029 mg/kg and 0.017 mg/kg residue. No residue was detected from brinjal and tomato samples collected at 8 DAS. But in cauliflower, no residue was detected at 10 days after spray. So, brinjal, tomato and cauliflower can be harvested safely at 4 DAS and 5 DAS for cypermethrin and in case of chlorpyrifos it was 8 DAS in brinjal and tomato and 10 DAS in cauliflower. Asian Australas. J. Biosci. Biotechnol. 2021, 6 (2), 60-67


2020 ◽  
Vol 16 (8) ◽  
pp. 989-1019
Author(s):  
Habibur Rahman ◽  
S.K. Manirul Haque ◽  
Masoom Raza Siddiqui

Background: Schizophrenia is a severe mental illness that affects more than twenty-one million people throughout the world. Schizophrenia also causes early death. Schizophrenia and other related psychotic ailments are controlled by the prescription of antipsychotic drugs, which act by blocking certain chemical receptors in the brain and thus relieves the symptoms of psychotic disorder. These drugs are present in the different dosage forms in the market and provided in a certain amount as per the need of the patients. Objective: Since such medications treat mental disorders, it is very important to have a perfect and accurate dose so that the risk factor is not affected by a higher or lower dose, which is not sufficient for the treatment. For accurate assay of these kinds of drugs, different analytical methods were developed ranging from older spectrophotometric techniques to latest hyphenated methods. Results: The current review highlights the role of different analytical techniques that were employed in the determination and identification of antipsychotic drugs and their metabolites. Techniques such as spectrophotometry, fluorimetry, liquid chromatography, liquid chromatography-mass spectrometry, gas chromatography, and gas chromatography-mass spectrometry employed in the method development of such antipsychotic drugs were reported in the review. Different metabolites, identified using the hyphenated techniques, were also mentioned in the review. The synthesis pathways of few of the metabolites were mentioned. Conclusion: The review summarizes the analyses of different antipsychotic drugs and their metabolites. A brief introduction of illnesses and their symptoms and possible medications were highlighted. Synthesis pathways of the associated metabolites were also mentioned.


2020 ◽  
Vol 16 ◽  
Author(s):  
Yun-Yan Xia ◽  
Qiao-Gen Zou ◽  
Yu-Fei Yang ◽  
Qian Sun ◽  
Cheng-Qun Han

Background: High-performance liquid chromatography (HPLC) method has been used to detect related impurities of perampanel. However, the detection of impurities is incomplete, and the limits of quantification and detection are high. A sensitive, reliable method is in badly to be developed and applied for impurity detection of perampanel bulk drug. Objective: Methodologies utilising HPLC and gas chromatography (GC) were established and validated for quantitative determination of perampanel and its related impurities (a total of 10 impurities including 2 genotoxic impurities). Methods: The separation was achieved on a Dikma Diamonsil C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase of 0.01 mol/L potassium dihydrogen phosphate solution (A) and acetonitrile (B) in gradient elution mode. The compound 2-bromopropane was determined on an Agilent DB-624 column (0.32 mm × 30 m, 1.8 μm) by electron capture detector (μ-ECD) with split injection ratio of 1:5 and proper gradient temperature program. Result: Both HPLC and GC methods were established and validated to be sensitive, accurate and robust according to International Council for Harmonization (ICH) guidelines. The methods developed were linear in the selected concentration range (R 2≥0.9944). The average recovery of all impurities was between 92.6% and 103.3%. The possible production mechanism of impurities during the synthesis and degradation processes of perampanel bulk drug was also discussed. Five impurities were analyzed by liquid chromatography–mass spectrometry (LC-MS). Moreover, two of them were simultaneously characterized by LC-MS, IR and NMR. Conclusion: The HPLC and GC methods were developed and optimized, which could be applied for quantitative detection of the impurities, and further stability study of perampanel.


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