Thumbnail Image

Theses

Browse

20213
Reset filters
Subject: Chemistry × End date: 2021 × Start date: 2021 × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemOpen Access
    Studies on persistence and leaching behaviour of ready pre-mix formulation (Chlorantraniliprole + Thiamethoxam) in/on tomato
    (CCSHAU, Hisar, 2021-10) Dhanker, Preeti; Sushil
    The study reports the uptake as well as the distribution pattern of insecticides, chlorantraniliprole and thiamethoxam in tomato plant matrices including root, stem, leaves and fruits from the soil via drench application of their ready-pre mix formulation chlorantraniliprole and thiamethoxam. For extraction and clean-up, three different methods namely liquid-liquid partitioning, QuEChERS with no clean-up and QuEChERS with clean-up were used in association with GC-MS/MS. The LOD and LOQ of the method determined were 0.01 μg g−1 and 0.005 μg g−1, respectively, and all the recoveries were above the range of 80 per cent. Rapid uptake of the insecticides by tomato plant was observed from the first day onwards. In the tomato plant, the major part of the insecticides got deposited in the roots and in the leaves. No presence of chlorantraniliprole and thiamethoxam residues were reported in tomato fruits which were much below their respective maximum residue limits (MRLs). In the soil samples, chlorantraniliprole residues for respective SD and DD were 0.389 and 0.788 μg g−1 initially which dissipated till day 20 reaching LOQ after that, while the thiamethoxam concentration were 0.682 and 1.335 μg g−1 initially, which dissipated till 20 and 25 days for SD and DD, respectively. in leaching experiment more than 85 per cent of the residues were recovered totally, with no residues in leachates
  • Thumbnail Image
    ThesisItemOpen Access
    Efficient and green multicomponent synthesis of some novel heterocyclic compounds and their bioefficacy
    (CCSHAU, Hisar, 2021-01) Gulati, Susheel; Rajvir Singh
    Due to growing concern of environmental pollution, the application of green chemistry for the formation of bioactive heterocyclic functionalities has turned out to be a key area of research for organic chemists. Coumarins, dihydropyrimidinones, imidazoles, isoxazoles and benzimidazoles are important heterocyclic compounds occur widely in nature. The conventional methods for preparation of these heterocyclic molecules have some drawbacks such as use of hazardous solvents, toxic reagents, tedious work-up, low product yield and long reaction time. Therefore, the development of waste minimized organic synthesis has become key and challenging area for organic chemist. Natural acid catalysts viz. Citrus limon L. juice, Vitis vinifera L. juice, Banana peels extract, Cocos nucifera L. juice, Solanum lycopersicum L. juice, Citrus limetta juice and Citrus sinensis L. juice were prepared for synthesis of substituted coumarins (30-37), dihydropyrimidinones (45-52), imidazole (55-62), isoxazoles (65-72) and benzimidazoles (73-80). All synthesized compounds were characterized by using 1HNMR and FTIR spectral techniques and evaluated for antibacterial activity against Erwinia carotovora and Xanthomonas citrii by inhibition zone method. All synthesized compounds were also tested for antifungal activity against Rhizoctonia solani and Colletotrichum gloeosporioides by poisoned food technique method. Herbicidal activity against Raphanus sativus L. (Radish seeds) were also studied to test bioefficacy of synthesized compounds. It was found that maximum Erwinia carotovora growth was inhibited by compounds 37, 51, 56, 72 and 78. Maximum Xanthomonas citri growth inhibition was by compounds 31, 50, 57, 72 and 74. Compounds 31, 50, 58, 72 and 76 were found to be the most active against Rhizoctonia solani fungus while compounds 34, 47, 58, 67 and 76 have highest growth inhibition against Colletotrichum gloeosporioides fungus. It was found that compounds 30, 51, 60, 67 and 79 were most active against Raphanus sativus L. (root) while compounds 31, 48, 57, 67 and 75 found to be most active against Raphanus sativus L. (shoot). It was found that the activity of the synthesized compounds may be due to presence of bromo, chloro, methyl, hydroxy, methoxy and nitro groups substitution on the phenyl ring.
  • Thumbnail Image
    ThesisItemOpen Access
    Dissipation kinetics of pyriproxyfen in chilli (Capsicum annum L.) and soil
    (CCSHAU, Hisar, 2021-02) Parveen Kumari; Duhan, Anil
    Pyriproxyfen, 2-[1-methyl-2-(4-phenoxyphenoxy)ethoxy] pyridine, is a novel broad spectrum insecticide. Dissipation of pyriproxyfen in chilli, soil and effects of washing on reduction of residues in chilli fruits were observed under field and lab conditions. Pyriproxyfen efficacy against honey bees, its leaching potential under continuous flow condition and the dissipation behaviour of its different metabolites formed in soil under field conditions was also studied. Field experiment was carried out in Research field of Department of vegetable Science, and lab study was performed in Agrochemicals Residues Testing Laboratory, Department of Agronomy, Chaudhary Charan Singh Haryana Agricultural University. Pyriproxyfen (Lano 10 EC) was applied on chilli crop and soil at two doses i.e., 100 (T1) and 200 (T2) g a.i./ha. Chilli and soil samples were collected periodically on 0 (2h), 1, 3, 7, 10, 15, 30 and 45 days after application. Various sample preparation techniques i.e. QuEChERS, Liquid-solid extraction (LSE) and Matrix solid phase dispersion (MSPD) were optimized for chilli and soil at different fortification levels (0.005-0.1 μg/g). Maximum recoveries (83.1 to 104.8%) for chilli were obtained using LSE, In soil, MSPD revealed 94.2 to 104.3% recoveries. The test samples were analysed over GC-MS/MS. A first order dissipation kinetics was followed with half-lives ranged from 4.7 to 8.1 days in chilli treated with pyriproxyfen under field and lab conditions and from 3.7 to 8.2 days in soil at two doses. The residues reached below MRL value (0.02 mg/kg) on 45 day in chilli under both conditions. In case of soil residues were below detection limit on 45 day in field samples and on 60 day in lab samples. Average reduction in residues due to washing was in the range of 54-56% under field conditions and 35-47% under lab conditions. Residues in wash water were ranged from 0.077 to 0.158 μg/mL in T1 and 0.091 to 0.316 μg/mL in T2 application under field conditions and 0.041 to 0.138 μg/mL in T1 and 0.066 to 0.337 μg/mL in T2 under lab conditions, respectively. During this study, six metabolites of pyriproxyfen were observed in soil namely 4-OH-PYR (A), POP (C), POPA (E), 4-OH-POPA (F), PYPA (G) and PYPAC (H). Dissipation study of the metabolites revealed their appearance on the day of pyriproxyfen application, reached to maximum concentration on 1 DAA in soil. All the metabolites except 4-OH-PYR persisted for more than 30 days in soil with half-lives ranged from 2.6 to 30 days. Higher dose was significantly more detrimental to honey bees. Leaching study do not showed any leaching potential of pyriproxyfen and almost whole of applied pyriproxyfen was retained within 0-5 cm soil depth.