A colorimetric version of the CIPAC method for measuring dilute emulsion stability

The characterisation of emulsions at dilution rates greater than the 1:20 used in most international specifications for agrochemical formulations is becoming increasingly important. The internationally-agreed CIPAC MT 36.2 test depends upon the determination of the shift in bulk concentration between the upper and lower halves of an emulsion after a period of standing. An analytical method specific to the active ingredient is stipulated. This paper reports an investigation of the use of CIPAC MT 36.2 with an emulsifiable concentrate (EC)-soluble dye which allows a colorimetric finish. This new method should be applicable to almost all ECs, and uses less costly instrumentation than the standard method. It could therefore allow more convenient use of CIPAC MT 36.2 for formulation development purposes. The limitations and range of applicability of the new method are discussed. For ECs of poor spontaneity it is shown that emulsion stability is strongly influenced by the emulsification technique used. Techniques within the frame of CIPAC MT 36.2 have been discovered which give repeatable results for such ECs.     

Development of a nephelometric version of the CIPAC method for measuring dilute emulsion stability

The characterisation of emulsions at dilution rates greater than 1:20, currently used in most international specifications for agrochemical emulsifiable concentrate (EC) formulations, is becoming increasingly important. CIPAC MT36.2 is the internationally-accepted test method for determining the bulk stability of emulsions containing 10 ml litre^?1 or less of added EC. A new nephelometric version of this test method has been examined which, although not as accurate as the official method, gives more rapid results. An assessment of the new method against the official method at a working concentration of 5 ml litre^?1 is reported. Agreement is good, despite the semi-empirical nature of the new method, but only if emulsions are re-emulsifiable at the end of the standing period. The scope of the method is discussed and areas of application indicated.     

Stability of emulsifiable concentrate pesticide formulations in liquid fertilizers

The stability of some diluted emulsifiable concentrate formulations in clear liquid fertilizers, as affected by the nature and concentration of the salt solutions, was checked by a static test. The time-induced changes in the concentration of the dispersed phase were estimated by visual observations and turbidity measurements. For each formulation a specific relationship between the electrical conductivity of all the fertilizer solutions and the emulsion stability was found. This was valid for a pH range between 4.6–6.3; in alkaline conditions the emulsion stability was relatively lower. A critical electrical conductivity range, above which irreversible destabilization occurred, was observed for each formulation: 100-120 dS m^?1 for fenamiphos, 60-70 dS m^?1 for metolachlor, 30-50 dS m^?1 for chlorpyrifos, and about 45 dS m^?1 for S-ethyl dipropylthiocarbamate (EPTC). The correlation observed between the emulsion stability and the electrical conductivity could be used in a simple and rapid qualitative test to estimate the physical compatibility between emulsifiable concentrate formulations and liquid fertilizers.     

辛硫磷乳油和神光乳油中辛硫磷的HPLC快速测定

在以50mm长的反相液谱短柱上实现了上辛硫磷乳油和神光乳油中辛硫磷的HOLC／UV快速分析,该方法的密度为辛硫磷乳油中辛硫磷的相对标准偏差4．3％,神光乳油中辛硫磷的RSD是3．65;辛硫磷乳油中辛硫磷的回收率102．5％,神光乳油中辛硫磷的回收率99．6％,为辛硫磷乳油和神光乳油中辛硫磷的仪器检测提供了一种经济、快速而又准确,可靠的方法。     

The effect of the physico-chemical stability of emulsions of an ester of 2, 4-D on their biological activity

The phytotoxicity of oil-in-water emulsions containing the ‘iso-octyl’ ester of 2, 4-D [(2, 4-dichlorophenoxy)acetic acid], prepared by the dilution of emulsifiable concentrates, to Phaseolus vulgaris, was found to be independent of the surfactant concentration (‘Synperonic NPE 1800’ + ‘Ethoduomeen T20’) and of the emulsion stability. Moreover, spray retention was also independent of the surfactant concentration within the range studied (0.01-150 g litre^?1); this could be accounted for in terms of the energetic processes involved during impaction, and the subsequent adhesion of the spray droplets to the target surface. However, the independence of the phytotoxicity of the surfactant concentration and emulsion stability was not expected, and some tentative explanations are given for these results.     

液体农药制剂中烷基酚及其聚氧乙烯醚类助剂的高效液相色谱分析

建立了一种测定6类液体农药制剂中烷基酚（alkylphenols,APs）及其聚氧乙烯醚类（alkylphenol ethoxylates,APEOs）助剂的高效液相色谱-荧光分析方法。乳油、水剂、水乳剂、悬浮剂、可溶液剂和微乳剂样品均经甲醇超声辅助提取,稀释后过聚丙烯膜,采用Poroshell 120 EC-C18（4.6 mm×100 mm,2.7 μm）分离,V（甲醇）:V（乙腈）:V（水）=75.5:6.5:18.0三元流动相等度洗脱,荧光检测器检测,外标法定量。结果表明:在0.05~10或0.1~20 mg/L范围内,APs和APEOs的峰面积与其质量浓度间呈良好线性关系（R2均大于0.999 8）;在添加水平范围内（APs:0.5、2、5 mg/g;APEOs:1、5、25、50 mg/g）,6类液体农药剂型中APs和APEOs的平均回收率为73%~110%,相对标准偏差为0.6%~14.9%,方法的定量限在0.5~1 mg/g。该方法简单、快速、准确,适用于不同液体农药制剂中烷基酚及其聚氧乙烯醚类助剂的测定。     

乳液聚合法制备阿维菌素微胶囊及其生物活性研究

利用乳液聚合法制备了阿维菌素微胶囊,其包裹率达99.98%,载药率达37.5%。用动态光散射粒度分析仪和冷场发射扫描电子显微镜进行了测试,结果显示,微胶囊颗粒平均粒径为278 nm,单分散性较好。渗透性与传导性试验结果表明,在植物体内,该阿维菌素微胶囊比乳油具有更好的渗透性与传导性。室内杀虫活性研究表明,该阿维菌素微胶囊制剂的杀虫活性与原药相近。     

七种农药对茴香薄翅野螟防效研究

用喷雾法防治油菜田茴香薄翅野螟,结果表明：0.5%甲氨基阿维菌素苯甲酸盐微乳剂、4.5%高效氯氰菊酯乳油、2.5%高效氯氟氰菊酯乳油和200 g/L氯虫苯甲酰胺悬浮剂4种农药对茴香薄翅野螟的防效随着施药次数增加而增加;40%灭多威可溶性粉剂和25%杀虫双水剂的防效随着施药次数的增加防效逐渐下降; 48%毒死蜱乳油在不同施药次数下防效变化幅度较小,平均防效在95.85%左右;上述7种农药喷施1次后, 以48%毒死蜱乳油和40%灭多威可溶性粉剂的防效最好,分别达96.03%和94.82%。4.5%高效氯氰菊酯乳油、2.5%高效氯氟氰菊酯乳油和48%毒死蜱乳油喷施2次和3次时的防效都在95.70%左右。     

加工方法对异丙甲草胺水乳剂物理稳定性的影响

通过分析Turbiscan Lab分散稳定性分析仪短期扫描图谱,以及测定所制备的水乳剂液滴平均粒径和Zeta电位,研究了不同加工方法(油水相添加顺序和乳化剂添加位置不同)对异丙甲草胺水乳剂物理稳定性的影响。结果发现:采用乳化剂添加在油相中的反相乳化法(方法 A)制备的水乳剂,短期扫描图谱中背散射光强度随时间降低的幅度很小,液滴平均粒径最小,Zeta电位绝对值最大,加速试验(54℃±2℃,14 d)后外观均一,稳定性最好;采用乳化剂添加在水相中的反相乳化法(方法 B)制备的水乳剂稳定性次之;采用乳化剂添加在水相中的直接乳化法(方法 C)和乳化剂添加在油相中的直接乳化法(方法 D)制备的水乳剂,试样短期扫描图谱中背散射光强度随时间均发生明显变化,顶部及中下部背散射光强度随时间呈更加明显的下降趋势,液滴平均粒径均较大,Zeta电位绝对值较小,加速试验后外观不均一,上层析水,下层产生少量沉淀,其中采用方法 C制备的水乳剂稳定性最差。表明采用不同加工方法制备的同一配方异丙甲草胺水乳剂的稳定性存在显著差异,以乳化剂添加在油相中的反相乳化法制备的水乳剂稳定性最好。     

含有机硅助剂的阿维菌素微乳剂的研制

研制了含有机硅助剂的阿维菌素微乳剂,并以常规阿维菌素微乳剂或乳油为对照,从制剂质量技术指标、理化性能及生物学效应等方面进行了评价。所配制的含有机硅助剂(Silwet 408)的1.8%阿维菌素微乳剂(含质量分数为6%的环己酮、4%的二甲基亚砜、7%的0203B和5%的Silwet 408,余量为自来水)不仅达到一般微乳剂的质量要求,阿维菌素热贮分解率为1.12%,有机硅助剂的热贮分解率也低于1%,而且通过溶剂优化,节约了70%的有机溶剂用量和7%的表面活性剂用量,还比常规微乳剂和乳油的表面张力降低10 mN/m左右、减小液滴接触角10°以上、增大液滴的扩展面积5 mm2以上,药液的润湿时间从乳油和常规微乳剂难于润湿降低到1 min以内。每公顷7.2 g (有效成分含量)含有机硅助剂的阿维菌素微乳剂对菜青虫的田间防效为96.8%,显著高于相同剂量的乳油制剂(防效94.5%);特别是低容量喷雾增效更为显著,每公顷3.6 g的微乳剂防效为88.4%,明显高于同剂量的大容量喷雾(防效82.7%)。试验结果表明,含有机硅助剂的阿维菌素微乳剂比常规微乳剂或乳油性能更为优越,防效更显著,特别适合于低容量喷雾。     

Complementary effect of Phloxine B on the insecticidal efficacy of Isaria fumosorosea SFP‐198 wettable powder against greenhouse whitefly,Trialeurodes vaporariorum West.

BACKGROUND: Insecticidal activities of five photoactive dyes against greenhouse whitefly (GWF), Trialeurodes vaporariorum West., in tomatoes were investigated to improve the control efficacy of an entomopathogenic fungal product, Isaria fumosorosea SFP‐198 wettable powder (WP). Azorubine, Eosin B, Erythrosine, Brilliant Green and Phloxine B were used in this work, accompanying pyriproxyfen emulsifiable concentrate (EC) as a commercial standard for comparison. RESULTS: Phloxine B had the highest control efficacy in glasshouse conditions. The most suitable dose of Phloxine B was determined as 0.005 g L^?1, given the dosage‐dependent control efficacy and phytotoxicity of the dye, and its influence on the germination of SFP‐198 conidia. In field conditions, SFP‐198 WP + Phloxine B (2 + 0.005 g L^?1; tank mix) showed 89.1 and 95.3% control efficacy 7 and 14 days post‐application, which was significantly higher than the efficacy of SFP‐198 WP alone (43.5 and 64.0%), Phloxine B (47.5 and 30.7%) or pyriproxyfen EC (67.7 and 80.2%). CONCLUSION: Phloxine B cooperates with SFP‐198 WP complementarily, possibly in the order of killing action (early: Phloxine B; late: SFP‐198 WP). The dye can be incorporated into SFP‐198 WP to improve its efficacy and applied to other Hypocrelean entomopathogenic fungal products. Copyright © 2010 Society of Chemical Industry     

印楝素和阿维菌素的液相色谱法同时测定

提出了一种可同时测定印楝素·阿维菌素乳油中印楝素和阿维菌素B1a的液相色谱法。该方法使用Hypersil ODS C18(250 mm×4 mm,5 μm)色谱柱和紫外检测器(印楝素λ 215 nm,阿维菌素B1a λ 240 nm),印楝素和阿维菌素B1a的回收率分别为97.5%~105.0% 和98.0%~107.5%,相对标准偏差分别为1.70%和1.60%,达到了简便、快速、准确的目的。     

农思它原粉及其乳油的气相色谱分析

本法以７％ＱＦ－１为固定液作填充柱，以磷酸三苯酯为内标物，在选定的ＧＬＣ条件下分别测定农思它原粉及其乳油的有效成分含量，其变异系数为０．１４％，回收率为１００．１％，相关系数为０．９９９８，农思它的保留时间是６．５ｍｉｎ，方法准确，方便且线性范围广，易于推广应用。     

Reinvestigating adjuvants for the wild oat herbicide,flamprop-M-isopropyl. I: Glasshouse trials

Commercial formulations of flamprop-M-isopropyl and formulations of other members of this class of herbicide have always contained an oil adjuvant to increase herbicidal performance. Further increases of performance could be obtained by following the label recommendations to add further quantities of a commercial emulsifiable oil (e.g. ‘Swirl’). Nevertheless it was judged that, in view of current advances in adjuvant research, even greater improvements in herbicidal performance could be obtained with different types of adjuvants. Experimental trials using a cultivated oat (Avena sativa L.) assay under glasshouse conditions to test ranges of surfactants (alkyl aryl, alkyl saccharide, alkylamine and alcohol ethoxylates) and emulsifiable oils (paraffinic/naphthenic, rape seed, transmethylated rape seed) showed that all of these adjuvants were capable of increasing flamprop-M-isopropyl activity compared with that of an emulsifiable concentrate formulation containing no adjuvant. Alkylamine and alcohol ethoxylates, with no particular preference for the length of the alkyl chain, but optimum ethylene oxide content of 5 moles and 7–10 moles respectively, were the most efficacious and better than the current emulsifiable oil system. There was no additional benefit from mixture of these two types of adjuvant and an alcohol ethoxylate (‘Dobanol’ 25-7) was preferred on cost grounds. This adjuvant also gave substantial activity to the otherwise inactive suspension concentrate formulation. Final trials determined that the optimum application rate of ‘Dobanol’ 25–7 was in the range 1000–1500 g ha^?1, and this information guided the design of subsequent field trials.     

Some aspects of tri-allate volatility

The volatility of tri-allate from different formulations when mixed with 2 soils containing water at 2%, 6% and field capacity was estimated in the laboratory. Volatility increased with increasing water content in each case. It was generally highest from an emulsifiable concentrate and lowest from a granule formulation with that from unformulated tri-atlate intermediate. In a greenhouse experiment rates of loss of tri-allate from a dry soil were similar for both emulsifiable concentrate and granule formulations, but from a wet soil and an aluminium foil dish losses were much greater from the emulsifiable concentrate. The persistence of trii-allate from granules applied in the field was virtually the same for granules containing 2.5, 5 or 10% active ingredient.     

浅谈农药乳油制剂面临的挑战

随着人类环境保护意识的增强,农药乳油制剂中使用大量的有机溶剂带来的安全和环保问题逐渐为人们所认识,农药乳油制剂面临着生死挑战。发展高质量浓度的乳油产品及开发天然植物源溶剂取代传统芳烃类有机溶剂。是农药乳油制剂的必然发展出路。     

农药乳油中7种助剂的顶空气相色谱测定方法

以25%毒死蜱-阿维菌素乳油为研究对象,采用顶空气相色谱,对农药乳油中二氯甲烷、三氯甲烷、1,1,1-三氯乙烷、苯、1,2-二氯丙烷、四氯乙烯和1,1,2,2-四氯乙烷7种有害助剂含量的多组分同时测定方法进行了研究。样品于顶空瓶中用体积分数为20%的二甲基甲酰胺水溶液溶解,密封后上下翻转15次,室温下静置过夜,80 ℃水浴30 min后,取顶空气体进行测定。方法的线性 决定系数大于0.995 0,除四氯乙烯和1,1,2,2-四氯乙烷外,其他5种助剂的添加回收率在74.4%~ 102.8%之间,定量限(LOQ)为0.2~5.0 mg/L。采用所建立方法对5种市售农药乳油中7种助剂的含量进行了分析,有部分助剂被检出。     

乳状液稳定性表征方法及其在农药水乳剂研发中的应用

乳状液被广泛应用于食品、石油、化妆品和农用化学品等领域,稳定性是影响其使用寿命和功能发挥的关键因素。因此,快速、准确地表征乳状液的稳定性一直被人们所关注。农药水乳剂是以乳状液为基础的农药剂型之一,具有高效、低毒和环保等优点。文章简要介绍了乳状液在食品和石油等领域的应用及研究现状,重点综述了液滴粒径及其分布测定、电导率测定、微观结构研究、拟三元相图研究和液滴表面电动性能研究等表征乳状液制备与使用过程中稳定性的主要手段,并总结了这些表征手段在农药水乳剂研究开发中的应用情况,旨在为缩短水乳剂配方研制周期和提高其稳定性提供参考。     

Effects of adjuvants on the performance of a novel powdery mildew fungicide, 1-(4-chlorobenzyl)-4-phenylpiperidine

The effects of adjuvants on the performance of a dispersible concentrate formulation (DCI) of a novel powdery mildew fungicide, 1-(4-chlorobenzyl)-4-phenylpiperidine (I) were investigated. The method involved assessment, under glasshouse conditions, of the therapeutic (curative) control of infections of powdery mildew (Erysiphe graminis DC f.sp. hordei Marchal) on barley (Hordeum vulgare, L.) eight to nine days after spray application to plants that had been inoculated one day prior to spraying. The results from the first trial showed that marked improvements (∽five-fold) in the performance of DCI could be obtained by the spray tank addition of some types of surfactant adjuvants and a series of further trials investigating a wide range of adjuvants was conducted. Nonylphenol, alkylamine and alcohol ethoxylates varying in mean ethylene oxide content between 5 and 20 moles were highly effective. There were indications that optimum performance enhancements were obtained with these surfactants containing between 5 and 10 moles ethylene oxide. Lower enhancements, sometimes only marginal, were obtained from trisiloxane, phosphate ester, propylene oxide, alkylamine-propylene oxide and castor oil ethoxylates and also alkyl polyglucoside biosurfactants. Negligible adjuvant enhancements were observed with emulsifiable paraffinic/naphthenic and rape seed oils, though slightly better enhancements were seen with an emulsifiable transmethylated rape seed oil and, interestingly, larger enhancements with an emulsifiable lipophilic alcohol. A final trial identified the alcohol ethoxylate, ‘Dobanol’ 91-6, as the most effective adjuvant and that its optimum application rate under glasshouse conditions was 250 g ha^-1. This information will be used to guide the design of field trials. © 1997 SCI     

Fate and persistence of residues on wheat used to explain efficacy differences between deltamethrin suspension concentrate and emulsifiable concentrate formulations

To help explain the increased residual activity of a deltamethrin suspension concentrate (SC) formulation against grasshoppers, the persistence, location and nature of residues from the SC and an emulsifiable concentrate (EC) formulation have been compared. Wheat plants were sprayed in a cabinet sprayer at 7.6 g ha^?1 for the EC and 5.6 g ha^?1 for the SC, then weathered outdoors for 16 days. With the SC formulation, residues were more persistent, more residues were located on the exterior of the leaves, and less deltamethrin was converted to inactive isomers. Eight days after spraying, the exterior deltamethrin residues were 0.13 μg plant^?1 from the SC versus 0.06 μg plant^?1 from the EC. Thus, more residual deltamethrin is available to grasshoppers with the SC formulation.