共查询到20条相似文献，搜索用时 46 毫秒
1.
The degradation of diuron photoinduced by iron(III) in aqueous solution has been investigated with different iron(III) species (monomeric species Fe(OH)2+, dimeric species Fe2(OH)24+ and water-soluble oligomeric species) under monochromatic excitation at 365 nm and under sunlight. The rate of degradation depends on the concentration in Fe(OH)2+, the most reactive species in terms of •OH radical formation. The major photoproduct is 3-(3,4-dichlorophenyl)-1-formyl-1-methylurea which represents more than 60% of diuron disappearance. The mechanism only involves the attack by •OH radicals arising from iron(III) excited species. The half-lives of diuron when submitted to such a process in the environment were estimated to be 1–2 h and a few days according to the concentration of Fe(OH)2+ (respectively 70% and <10% of total iron(III) concentration). 相似文献
2.
Ilker Angin Serdar Sari Ekrem Lutfi Aksakal Faruk Tohumcu 《Arid Land Research and Management》2019,33(1):91-96
Accelerated soil salinization is a worldwide concern. Our study was carried out to determine the effects of different rates (0, 5, 10, and 15?mmol kg?1) of iron (III) ferrocyanide application to remove salts from the soil. Within two weeks of its application, iron (III) ferrocyanide at 5, 10, and 15?mmol?kg?1 removed 12.2%, 26.5%, and 42.9% of the total salts from the soil, respectively. Results suggested that iron (III) ferrocyanide application at 15?mmol?kg?1 is one of the most rapid and effective ways to remove substantial amounts of salts from undrained soil (land) where fresh water is scarce. 相似文献
3.
Suzanne J. Clark Nicola P. Coward Glenn W. Dawson Ian F. Henderson Andrew P. Martin 《Pest management science》1995,44(4):381-388
Two related iron chelates, one toxic to slugs by ingestion, the other not, were introduced into the foregut of D. reticulatum. The subsequent movement and redistribution of the metal within the slug tissues was studied by labelling the chelates with the radioactive isotope 55Fe. In slugs which survived treatment approximately half of the 55Fe was voided in faeces. The iron retained became unevenly distributed, the highest concentration occurring in the digestive gland, irrespective of the chelate used. At high doses, slugs treated with tris(1-oxo-1,2-diazabutan-2-oxido)Fe(III) were fatally poisoned while those treated with the homologue, tris(1-oxo-1,2-diazaoctan-2-oxido)Fe(III) were not. Slugs killed by the toxic chelate consistently contained proportionally less iron in the digestive gland and proportionally more in the body wall and reproductive system. Dosing slugs already killed by carbon dioxide asphyxiation gave a similar pattern, suggesting that the greater mobility of the iron from the toxic chelate was not a function of the slugs' metabolism. 相似文献
4.
Two iron chelates, one toxic (iron ‘butan’) and the other not (iron ‘octan’), were ingested by slugs (Deroceras reticulatum) at either a low (5 g kg−1 diet) or a high (100 g kg−1 diet) dose rate. In tissue sections of the digestive gland and body wall, iron was detected by energy-filtering transmission electron microscopy (EFTEM), using electron spectroscopical imaging (ESI) and electron energy-loss spectroscopy (EELS). The strongest signals for iron were obtained in secondary lysosomes of the resorptive cells in the digestive gland of slugs treated with a low dose of either compound, or with the high dose of iron ‘octan’. At the cell apices of these cells, in endocytotic vesicles and in apically located lysosomes, iron was detected only in slugs fed with either dose of iron ‘octan’. In slugs fed with the high dose of iron ‘butan’, iron could clearly be localised in the epithelial and mucus cells of the skin. The results are discussed with respect to differences in the toxicity of the two iron chelates. © 1999 Society of Chemical Industry 相似文献
5.
A spectrophotometric method has been developed for the determination of ziram (zinc bis(dimethyldithiocarbamate)) and zineb (zinc ethylenebisdithiocarbarnate) by converting these into a zinc-4-(2-pyridylazo)resorcinol complex, which is dissolved in acetone and water and the absorbance measured at 490 nm against a reagent blank. Beer's law is obeyed over the concentration ranges 0.025-1.25 and 0.025-1.5 mg litre?1 for ziram and zineb respectively in the final solution. The method is sensitive and can be used for the direct determination of ziram and zineb in commercial formulations, grains (rice and wheat) and synthetic mixtures (in the presence of various other dithiocarbamates). The limit of determination of ziram and zineb from foodstuffs in 0.2 mg kg ?1. 相似文献
6.
Tomoko Nagata 《Pest management science》1997,51(1):27-32
2,4,5-T was extracted with acetone at below pH 1·0 and the extract was concentrated. After adding 100 g litre-1 sodium chloride solution to the residual solution, 2,4,5-T was extracted with ethyl acetate+hexane (20+80 by volume). The extract was evaporated to dryness and the residue was dissolved in acetonitrile. 18-crown-6, potassium fluoride and NE-OTf were added to the acetonitrile solution and then allowed to react at 50°C for 20 min. The product was injected to a HPLC with ultraviolet detection operated at 259 nm and fluorometric detection at 394 nm emission and 259 nm excitation. The determination limits of the 2,4,5-T derivative in the sample were 20 μg litre-1 with UV detection and 10 μg litre-1 with fluorometric detection. © 1997 SCI. 相似文献
7.
Curcuminoids, the major colouring constituents of Curcuma longa (turmeric) rhizome powder, comprise mainly three closely related curcumins (I, II and III). A simple method has been devised for their efficient extraction and separation. Their structures have been confirmed by 1H NMR spectroscopy and unique mass fragmentation pattern. Curcumin‐I, the major constituent has been converted to five alkyl ether derivatives, which have been tested along with the parent compounds and other extractives for insect growth inhibitory activity against Schistocerca gregaria and Dysdercus koenigii nymphs. At 20 µg per nymph, benzene extract and dibutyl curcumin‐I were the most active (60% inhibition) against S gregaria, whereas at 50 µg per nymph these substances exhibited moderate growth‐inhibitory activity (45%) against D koenigii nymphs. At these concentrations, turmeric oil caused 50–60% nymphal mortality in both test insects. The insect control activity of most of the turmeric products was comparable to or better than that of a commercial neem formulation. © 2000 Society of Chemical Industry 相似文献
8.
Fánor Casierra-Posada Michael M. Blanke Juan Carlos Guerrero-Guío 《Gesunde Pflanzen》2014,66(2):63-68
Excess iron in soils affects many agricultural areas worldwide, causing great losses in cultivated plants particularly in waterlogged environments. Plants, such as the calla lily (Zantedeschia aethiopica), which grows in such wetlands, have been widely used for the treatment of wastewater. White calla lily plants were grown hydroponically from seeds in a greenhouse in Tunja, Colombia, under either of three different levels of iron (0, 100 or 200 ppm Fe) to evaluate the plant’s tolerance to excess iron. The total dry mass production, water uptake, water use efficiency (WUE), dry matter partitioning and root to shoot ratio were recorded four months after transplanting. The dry mass production per plant decreased as the iron level increased. Although water uptake decreased inversely proportional to the iron level, the WUE was not affected by iron. On the other hand, iron affected dry matter partitioning to the plant organs, accumulating more dry matter in the roots than in the shoot with higher iron levels. Hence, we suggest that the calla plant is moderately tolerant to excess iron and would be appropriate for the phytoremediation of wetlands contaminated with this metal. 相似文献
9.
The photoinduced degradation of three anilinopyrimidine fungicides (cyprodinil, pyrimethanil and mepanipyrim) by Fe(III)-polycarboxylate complexes in aqueous solution was investigated. A photochemical redox reaction of Fe(III) complexes of oxalate and citrate occurs during irradiation (simulating sunlight) and is an important source of Fe(II) and a series of oxidants such as H2O2 and O radicals. The mechanism involves the formation of polycarboxylate radicals and/or carbon-centred radicals derived from decarboxylation, whereas the contribution of Fe(OH)2+ to O radical formation is negligible. The attack of O radicals on the fungicide molecules produces numerous photodegradation products, which were identified by means of LC-ES-MS and turned out to be mono- or dihydroxylated derivatives of the active ingredients, except for 2-amino-4,6-dimethylpyrimidine, which is only formed by pyrimethanil. The half-lives of the active ingredients, when submitted to irradiation in the presence of iron(III)-polycarboxylate complexes, were estimated to vary between 28 and 79 min (photodegradation rates in the same conditions: mepanipyrim > cyprodinil > pyrimethanil), and photodegradation is slower in citrate than in oxalate solutions. Photoproducts and their kinetics of formation are very similar for the three fungicides. The OH substitution involves the aromatic and the heterocyclic ring and the nitrogen bridge between the two rings, except for mepanipyrim when the hydroxylation also involves the propynylic side chain. 相似文献
10.
A procedure has been developed for the determination of ferbam (ferric dimethyldithiocarbamate) by converting it into ferbam-phenanthroline complex, which is dissolved in acetone + water (1 + 1 by volume), and the absorbance measured at 490 nm against a reagent blank. Beer's law is obeyed over the concentration range 0–8–20-0 mg litre?1 in the final solution. The method is sensitive, selective and can be used for the direct determination of ferbam in commercial samples, in mixtures with various other dithiocarbamates (ziram, zineb, maneb, etc.) and from grains (rice and wheat) and apples. The limit of determination from foodstuffs is 0–4 mg kg?1. 相似文献
11.
Beresford L. Cadogan Dean Thompson Arthur Retnakaran Roger D. Scharbach Arthur Robinson Bozena Staznik 《Pest management science》1998,53(1):80-90
A field trial was conducted in 1994 to determine the foliar deposit of tebufenozide (RH5992), applied aerially, and its efficacy against spruce budworm, Choristoneura fumiferana (Clem.). A commercial 240 g litre-1 formulation of the insecticide (Mimic 240LV) was mixed with water, dyed with a tracer dye (Rhodamine WT) and sprayed with a light fixed-wing aircraft. Six application strategies were tested. Five used 70 g AI ha-1 in a spray volume of 1 or 2 litre-1 ha-1 with single or double applications; the sixth was an unsprayed control. Results show that the spectra of the spray applications were, with one exception, fairly uniform. Volume and number median diameters ranged from 100 to 130 μm and 27 to 72 μm, respectively. Mean number of drops cm-2 on Kromekote cards were <2·0 for strategies where either 1 or 2 litre ha-1 were sprayed. Nevertheless no one strategy produced droplet densities that were significantly different (P<0·05) from the other strategies. Tebufenozide recovered from foliage averaged 2·5 to 5·9 μg g foliage-1 when 1 litre ha-1 was sprayed and 5·8 to 6·8 μg g foliage-1 after 2 litre ha-1 were sprayed. When a single application was the strategy used, the mean number of droplets cm-2 and μg tebufenozide g foliage-1 ranged from 1·2 to 1·4 and 2·5 to 5·9, respectively. With double applications, the same response parameters ranged from 0·3 to 1·9 and 2·5 to 6·8, respectively. Budworm population reductions (%) and the number of larvae that survived tebufenozide treatments were significantly different (P<0·05) from the controls. After strategies that used 1 litre spray ha-1, mean percentage population reductions ranged from 61·4 to 93·6 whereas populations were reduced by 85·6 to 98·3% when 2 litre ha-1 were sprayed. After double applications the mean percentage population reductions ranged from 93·6 to 98·3, but single application strategies resulted in mean reductions of 61 to 86%. Mean population reductions in the controls were 61%. The mean number of larvae per branch that survived spray strategies of 1 litre ha-1 ranged from 1·3 to 7·4, and from 0·4 to 1·3 when 2 litre ha-1 was the spray volume. In the controls an average of 10·2 larvae survived. With one exception, mean percentage defoliation in the treated areas was also significantly less (P<0·05) than that in the control. Mean defoliation in trees sprayed at 1 litre spray ha-1 ranged from 40 to 62·8% whereas those treated at 2 litre ha-1 had mean defoliation levels from 31·5 to 62·8%. In contrast, average defoliation in the controls was 92·1%. When a single application was the spray strategy, mean defoliation ranged from 31·5 to 62·8%. These data imply that a double application of tebufenozide at 70 g in 2 litre ha-1 was the most efficacious strategy. However, analyses of the data also show that the primary influence on deposits and defoliation was interactions between number of applications and spray. Nevertheless the two independent variables acted without significant interactions when influencing percentage reductions of spruce budworm populations. © 1998 SCI 相似文献
12.
Controlled-release herbicide formulations have been shown to decrease the leaching potential of several herbicides under laboratory and field conditions. The utility and efficacy of these formulations may be improved by combining several herbicides and a fertilizer source in a single formulation. The objective of these studies was to develop granular alginate formulations that were composed of a combination of the herbicides atrazine and alachlor with the slow-release nitrogen source oxamide (ethanediamide). Controlled release of the herbicides was obtained by addition of selected minerals, including calcium bentonite, fine-grind bentonite, montmorillonite K10, kaolinite and iron (III) oxide. A formulation without clay was used as a comparison. The formulations tested had herbicide active ingredient contents ranging from ∽0·02 to 0·54% and a nitrogen content of 21%. Release of the herbicides was studied by equilibrating the formulations with deionized water on a rotary shaker at 200 rev min-1 and sampling at regular time intervals up to 104 hours. The minerals used in the different formulations influenced the herbicide active ingredient composition, as well as the release properties of the individual formulations. The atrazine content of the formulations decreased in the order calcium bentonite>fine-grind bentonite>kaolinite>montmorillonite=iron oxide>no clay. For alachlor the content decreased in the order of calcium bentonite>fine-grind bentonite>montmorillonite>iron oxide>kaolinite>no clay. Controlled release of atrazine (i.e. reduction in release rate) varied in the order calcium bentonite>iron oxide>montmorillonite>fine-grind bentonite= kaolinite>no clay, and for alachlor fine-grind bentonite>calcium bentonite>montmorillonite>no clay=kaolinite=iron oxide. A certain percentage of the applied active ingredient of both alachlor and atrazine was not recovered. From 5 to 27% of the active ingredient was not released, with the greatest retention by the bentonite formulations. Release of nitrogen was not strongly influenced by mineral type, although a trend indicated greater release with formulations containing kaolinite. © 1998 SCI 相似文献
13.
A rapid, simple, direct and sensitive method has been developed for the determination of thiram (tetramethylthiuram disulphide) based on the formation of copper dimethyldithiocarbamate complex, which is rendered water-soluble by a cationic surfactant, cetytrimethylammonium bromide (CTAB). The method has been applied to the determination of thiram in synthetic mixtures, grain (wheat) samples and vegetables. © 1998 SCI 相似文献
14.
An analytical procedure to detect N-(3-ethylsulfonyl-2-pyridinyl)-4,6-dimethoxy-2-pyridineamine, a degradation product deriving from the hydrolysis of rimsulfuron in soil, has been developed. The analytical standard was prepared by basic hydrolysis of rimsulfuron at pH 9 and purification on a silica gel chromatographic column. The compound obtained was stable at high temperature, thus enabling determination by gas chromatographic analysis. Soil samples were extracted with acetonitrile, purified with a SPE C18 cartridge and analysed using both nitrogen phosphorus (NPD) and mass spectrometer detectors. The analytical procedure described proved to be sensitive and reproducible. Recoveries varied from 84 to 90%. The limit of sensitivity was 0·001 mg kg-1. © 1997 SCI. 相似文献
15.
Tomas Berglf William C Koskinen Henrik Kylin Thomas B Moorman 《Pest management science》2000,56(10):927-931
Sorption–desorption of the fungicide triadimefon in field‐moist silt loam and sandy loam soils were determined using low‐density supercritical fluid extraction (SFE). The selectivity of SFE enables extraction of triadimefon from the soil water phase only, thus allowing calculation of sorption coefficients (Kd) at field‐moist or unsaturated conditions. Triadimefon sorption was influenced by factors such as soil moisture content and temperature; sorption increased with increased moisture content up to saturation, and decreased with increased temperature. For instance, Kd values for triadimefon on the silt loam and the sandy loam soils at 40 °C and 10% water content were 1.9 and 2.5 ml g−1, respectively, and at 18% water content, 3.3 and 6.4 ml g−1, respectively. Isosteric heats of sorption (ΔHi) were −42 and −7 kJ mol−1 for the silt loam and sandy loam soils, respectively. Sorption–desorption was also determined using an automated accelerated solvent extraction system (ASE), in which triadimefon was extracted from silt loam soil by 0.01 M CaCl2. Using the ASE system, which is basically a fast alternative to the batch equilibration system, gave a similar ΔHi value (−29 kJ mol−1) for the silt loam soil (Kf = 27 µg1 − 1/n ml1/n g−1). In order to predict transport of pesticides through the soil profile more accurately on the basis of these data, information is needed on sorption as a function of soil water content. © 2000 Society of Chemical Industry 相似文献
16.
A. Golizadeh M. Alikhani M. Hassanpour A. Enkegaard H. Rafiee-Dastjerdi J. Razmjou 《国际虫害防治杂志》2017,63(4):364-370
Habrobracon hebetor Say is an ectoparasitoid that has been used as a control agent of various lepidopteran pests. Temperature-dependent life table and thermal characteristics of H. hebetor are important in understanding the dynamics of host–parasitoid relationships and for optimizing biocontrol programmes. The influence of five constant temperatures (15, 20, 25, 30 and 35 °C) on the biology of H. hebetor when parasitizing Anagasta kuehniella Zeller was studied. The survival rate of immature stages increased from 16.67% to 83.81% as temperature increased from 15 to 30 °C and then decreased at 35 °C. Total development time ranged from 45.70 days at 15 °C to 7.10 days at 35 °C. The lower temperature threshold for immature stages varied slightly around a value of 11–12 °C. The net reproductive rate (R0) values were significantly different among temperatures and the highest value was found at 30 °C (85.10). The high survival rate and net reproductive rate combined with a relatively short generation time at 30 °C resulted in the intrinsic rate of increase (rm) being highest (0.312 d?1) at this temperature. Considering the acquired results, the temperature range between 25 and 30 °C was optimal for H. hebetor. 相似文献
17.
研究了 10 %千金乳油 (有效成分 :氰氟草酯 )和 78%杀虫安可溶性粉剂对金鱼和麦穗鱼肝脏酯酶及谷胱甘肽-S-转移酶 (GST)活性的亚致死剂量效应。发现杀虫安 (0 .2 34mg· L-1)对两种鱼的 GST活性均具诱导作用 ,而氰氟草酯 (1,2 mg· L-1)仅诱导了麦穗鱼的 GST活性 ;当杀虫安与氰氟草酯混合处理时 ,对麦穗鱼 GST活性的诱导效应最为明显。在一定的浓度范围内 ,氰氟草酯 (1,2 mg· L-1)和杀虫安 (0 .117,0 .2 34mg· L-1)均可诱导金鱼肝脏酯酶活性 ;对麦穗鱼肝脏酯酶而言 ,杀虫安为诱导作用 ,氰氟草酯则抑制其活性。研究结果表明 :两种酶的活性直接或间接地受供试药剂的影响 ,两种试鱼对氰氟草酯和杀虫安的生物反应存在差异。 相似文献
18.
Treatment of malaoxon with the anhydrous chlorides of zinc (II), manganese (II) copper (II) and iron (III) in carbon tetrachloride below 10° yielded solid compounds corresponding to a (1:1) composition. The infrared spectra of these compounds show coordination through the P = O bond. 相似文献
19.
超高效液相色谱法测定土壤中多杀菌素和乙基多杀菌素的残留 总被引：1，自引：1，他引：0
建立了土壤中多杀菌素(spinosad)A和D以及乙基多杀菌素(spinetoram)J和L残留量的超高效液相色谱(UPLC)检测方法。土壤样品经乙腈-5%氯化钠溶液-1 mol/L氢氧化钾溶液提取,固相萃取柱净化,UPLC检测,外标法定量。结果表明:土壤中多杀菌素和乙基多杀菌素的定量限分别为0.1和0.05 mg/kg;最小检出量分别为8.0×10-7和2.8×10-7g;在0.1~2 mg/kg添加水平下,多杀菌素在土壤中的平均回收率为89%~96%,相对标准偏差(RSDs)为2.1%~4.9%;在0.05~0.5 mg/kg添加水平下,乙基多杀菌素在土壤中的平均回收率为86%~93%,RSDs为1.2%~8.1%。该方法提取效果好,具有良好的灵敏度、回收率和重复性。 相似文献
20.
Richard F. Holt 《Pest management science》1979,10(6):455-459
Residues of the fungicide 1-(2-cyano-2-methoxyiminoacetyl)-3-ethylurea (DPX-3217) in grapes, potatoes, tomatoes and wine were determined by initial extraction with ethyl acetate, clean-up by liquid-liquid partitioning and adsorption chromatography, and final determination by gas-liquid chromatography with a nitrogen-selective detector. The sensitivity of the method was 0.04 mg kg?1 based on 50-g samples. Recoveries of the compound added to untreated substrates averaged approximately 92% in the range of 0.04-5.0 mg kg?1. 相似文献