高效液相色谱法同时测定稻田中苄嘧磺隆和苯噻酰草胺残留

建立了同时测定稻田(稻田土壤、水和植株)中苄嘧磺隆和苯噻酰草胺残留量的高效液相色谱(HPLC)分析方法。稻田水样品用二氯甲烷直接萃取;稻田土壤样品用碱性乙腈-二氯甲烷(1:1, v/v)混合液直接提取;水稻植株样品用碱性二氯甲烷提取后,二氯甲烷提取液经弗罗里硅土柱净化。上述样品溶液采用C18不锈钢色谱柱(150 mm×4.6 mm, 5 μm)分离,流动相为水-甲醇(30:70, v/v),流速为0.5 mL/min,柱温为30 ℃,紫外检测波长为238 nm,外标法定量。苄嘧磺隆和苯噻酰草胺在0.05～5.00 mg/L范围内的线性关系均很好(r＞0.9999)。在稻田水、土壤和水稻植株中添加3个水平(0.05, 0.10, 1.00 mg/kg)的苄嘧磺隆和苯噻酰草胺,两者的回收率均在85.39%～113.33%之间,相对标准偏差为0.91%～10.24%。这表明该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。     

Detection of Aryloxyphenoxypropionate Herbicides by Enzyme-Linked Immunosorbent Assay

In this study, we developed a general and broad class-selective indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for detecting aryloxyphenoxypropionate herbicides. A multideterminant artificial antigen was prepared from haptens of two herbicides (fenoxaprop-p-ethyl and cyhalofop-butyl) conjugated to the carrier protein Bovine serum albumin (BSA). The polyclonal antibodies (PAbs) were obtained by immunizing New Zealand white rabbits. Characterization studies of the PAbs showed that they had high affinity and specificity for the two herbicides. The 50% inhibitory concentration (IC₅₀) values for fenoxaprop-p-ethyl and cyhalofop-butyl were 0.185 mg L^?1 and 0.045 mg L^?1 with a limit of detection (LOD, IC₁₀) of 0.004 mg L^?1 and 0.002 mg L^?1, respectively. There were no obvious cross-reactivities with most of the aryloxyphenoxypropionates tested, except for metamifop (CR% = 55.56%). The recoveries of fenoxaprop-p-ethyl, cyhalofop-butyl and metamifop in environmental and agricultural samples (tap water, paddy water, soil, rice and soybean) ranged from 86.86–114.52%, 82.07–119.11% and 82.51–114.46%, respectively. These results demonstrate that the established ELISA could be used as a tool for detecting aryloxyphenoxypropionate multiresidues.     

Determination of Some Herbicides by Ring-Oven Technique

Abstract

A Weisz ring-oven technique is described for estimation of some herbicides, using a combination of NaNO₂ and N-1-naphthyl-ethylenediamine dihydrochloride as a spraying reagent for amiben and methanolic NaOH for diquat and paraquat.     

Electrochemical Reduction Behavior and Polarographic Determination of Methoxy Triazine Herbicides in Environmental Samples

The electrochemical reduction behavior of 1,3,5-triazine herbicides, Atraton (AN), Prometon (PN), Secbumeton (SN), and Terbumeton (TN) at mercury electrodes was studied in aqueous Britton Robinson buffer (BR) solutions by using different voltammetric techniques. The nature of the electrode process was examined. Number of electrons involved in the reduction process of all the four compounds was evaluated and a reduction mechanism was proposed. The electrolysis products were separated and identified by IR spectra. For analytical purposes, BR buffer of pH 4.0 was chosen as working medium for all the four analytes. The detection limits were found to be 1.5 × 10^?8 mol l^?1, 2 × 10^?8 mol l^?1, 2.8 × 10^?8 mol l^?1, and 1 × 10^?8 mol l^?1 for AN, PN, SN, and TN, respectively. A differential pulse voltammetric method was developed for the determination of these compounds in agricultural formulations, water, and soil samples. The interference from the ions and other herbicides were also evaluated.     

两种离子源技术气相色谱-质谱法检测茶叶中酰胺类除草剂的残留量

采用电子轰击(EI)和负化学(NCI)离子源两种离子源技术气相色谱-质谱联用法(GC     

固相萃取/高效液相色谱法测定地表水中磺酰脲类农药的研究

建立了固相萃取/高效液相色谱法(SPE/HPLC)同时测定地表水中五种磺酰脲类农药的方法。研究了固相萃取提取、净化方法,优化了高效液相色谱条件并用二极管阵列检测器进行定量分析。五种磺酰脲类农药在0.1~10.0μg/mL范围内线性良好,相关系数在0.9992~0.9998之间,相对标准偏差在1.8%~4.1%之间,平均回收率为72.8%~103%。本方法中五种磺酰脲类农药的检出限在0.02~0.22 ng/mL范围。用该法分析了某水域地表水,取得满意结果,表明本方法具有一定的实用性。     

Formation of derivatives of chlorophenoxy acids and some other herbicides

Summary A fuming sulphuric acid-ethanol esterification method has been applied to chlorophenoxy acids and some other herbicides. This method is compared with esterification by iodoethane and diazomethane. The chlorophenoxy acids studied were: 2,4-D, dichlorprop, MCPA, MCPB, mecoprop and 2,4,5-T. Other herbicides studied were: benazolin, bentazone, bromophenoxime, bromoxynil, chlorthal, dicamba, 3,6-dichloropicolinic acid, dinoseb, ethephon, fluroxypyr, glyphosate, haloxyfop, ioxynil, picloram, 2,3,6-TBA and triclopyr. Fuming sulphuric acid-ethanol esterification can be successfully applied to chlorophenoxy acids, benazolin, 3,6-dichloropicolinic acid, dinoseb, fluroxypyr, haloxyfop, picloram and triclopyr. The reproductibility of the method is ±5%.     

Rapid and sensitive detection of the phenoxy acid herbicides in environmental water samples by magnetic solid‐phase extraction combined with liquid chromatography–tandem mass spectrometry

Phenoxy acid herbicides are widely used herbicides that play an important role in improving the yield and quality of crops. However, some research has shown that this kind of herbicide is poisonous to human and animals. In this study, a rapid and sensitive method was developed for the detection of seven phenoxy acid herbicides in water samples based on magnetic solid‐phase extraction followed by liquid chromatography and tandem mass spectrometry. Magnetic amino‐functionalized multiwalled carbon nanotubes were prepared by mixing bare magnetic Fe₃O₄ nanoparticles with commercial amino‐functionalized multiwalled carbon nanotubes in water. Then the amino‐functionalized multiwalled carbon nanotubes were used to enrich phenoxy acid herbicides from water samples based on hydrophobic and ionic interactions. The effects of experimental variables on the extraction efficiency have been studied in detail. Under the optimized conditions, the method validation was performed. Good linearities for seven phenoxy acid herbicides were obtained with squared regression coefficients ranging from 0.9971 to 0.9989. The limits of detection ranged from 0.01 to 0.02 μg/L. The method recoveries of seven phenoxy acid herbicides spiked at three concentration levels in a blank sample were from 92.3 to 103.2%, with inter‐ and intraday relative standard deviations less than 12.6%.     

Separation of the Phenoxy Acid Herbicides and Their Enantiomers by Capillary Zone Electrophoresis in Presence of Highly Sulphated Cyclodextrins

The study of the chiral compounds and their fate in the environment is receiving an increasing attention — enantiomeric ratios are being measured and enantioselective degradation processes are being reported. It is particularly important with the toxic compounds like the pesticides, which are being freely used in the environment to control the harmful pests. Capillary zone electrophoresis was used for the chiral and mutual separation of four phenoxy acid herbicides using highly sulphated cyclodextrins (HSCD) in the buffer. The CE runs were performed with reverse polarity (anode in the outlet vial) using the acidic ammonium formate buffer (20 mmol, pH 3). Under these conditions of suppressed the electroendoosmotic flow (EOF), the analytes are mobilized to the anode by entering into host guest relation with the migrating negatively charged sulphated cyclodextrin. The phenoxy acid herbicides selected for the purpose were fenoprop, dicloprop, mecoprop and 2,4‐DB. The α‐HSCD and β‐HSCD have been tested as resolving agents in the CE for the separation of the enantiomers of the herbicides. Though the chiral separation of the dicloprop and mecoprop were achieved with α‐HSCD but it was not able to resolve fenoprop. With β‐HSCD the required base line separation was achieved. Potential difference selected was 10 kV. The limit of detection (S/N= 3) achieved in present case is 0.15 ppm for fenoprop, 0.14 ppm for dicloprop and mecoprop and 0.11 ppm for 2,4‐DB.     

Mathematical modeling of controlled-relase kinetics of herbicides in a dynamic-water-bath system

Applied Biochemistry and Biotechnology - Release of herbicides from lignin-based formulations follows a diffusion-controlled mechanism. For mathematical modeling of diffusive transport, the...