Evaluation of the Fate of Aldicarb and Its Metabolites in Oranges

Abstract

The accumulation, persistence and fate of systemic pesticide aldicarb was melencholy evaluated in orange crops. The concentration of this pesticide and its two toxic metabolites, aldicarb sulfoxide and aldicarb sulfone was determined in leaves, rind and pulp of three orange varieties (Satsuma, Navelina and Clemetina de Nules) and in the top soil of the orange groves. The groves were located in two different places in the Valencia Community (Spain). The analysis showed that the aldicarb concentration was lower than those of aldicarb sulfoxide and aldicarb sulfone. In all cases, the residues persisted at least 160 days in vegetable samples and between 157 and 227 days in soil samples. Residue concentrations measured in the soil samples were highly variable but a relation with the organic matter content can be observed. The residue levels found in vegetal products were higher in leaves than in rind, and in rind than in pulp. The maximum residue values were obtained between 47 and 70 days after the application. One hundred days after treatment (Security period) the residue levels of total fruit were lower than the maximum residue level of 0.2 mg/kg established by law.     

A New Hapten for Immunoassay of Aldicarb

Aldicarb, 2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoyl)oxime, is a systemic N-methylcarbamate insecticide and has been used on a variety of crops. It is moderately water soluble and considered as one of the most acutely toxic pesiticides. Ald…     

气相色谱法测定卷烟烟气中涕灭威残留量

提出了气相色谱法测定卷烟烟气中涕灭威残留量的分析方法。通过吸烟机抽吸捕集卷烟主流烟气总粒相物和主流烟气气相物后经甲醇萃取,所得萃取液中涕灭威及其代谢物通过过氧化氢氧化转化为涕灭威砜,再用二氯甲烷提取除去干扰,然后采用DB-1701弹性石英毛细管柱分离,脉冲火焰光度检测器检测,外标法定量。方法的检出限(3S/N)为0.01μg·g~(-1),主流烟气总粒相物中涕灭威的回收率在99.0%～101.0%之间,相对标准偏差(n=6)为4.7%～10.2%;主流烟气气相物中涕灭威的回收率在97.7%～99.3%之间,相对标准偏差(n=6)为5.4%～9.6%。     

Monoclonal Antibodies Useful in Sensitive Immunoassays for Aldicarb in Either Laboratory or the Field

Although polyclonal antisera have been used for immunodiagnostic measurement of aldicarb, both as components of commercial kits and as stand-alone products, no monoclonal antibody (MAb) reactive to this carbamate pesticide has yet been described. We have generated two MAbs with specificity to aldicarb, which function in our prototypic field immunoassays to identify this chemical in water samples. Further exploitation of these inherently stable immunoreagents should be valuable for point-of-need testing for the presence of aldicarb.     

固相萃取-同位素稀释-超高效液相色谱-串联质谱法测定水中涕灭威、涕灭威亚砜和涕灭威砜

采用同位素稀释结合固相萃取对水样进行预处理,建立了环境水体中涕灭威及其代谢物(涕灭威亚砜、涕灭威砜)的超高效液相色谱-串联质谱分析方法.水样加同位素内标涕灭威-D3、涕灭威亚砜-D3和涕灭威砜-D3,经HLB固相萃取柱富集净化后,用Waters ACQUITYTM BEH C18色谱柱(2.1 mm×100 mm,1....     

Use of XAD-2 Macroreticular Resin for the Recovery of Aldicarb and its Metabolites in Drinking Water

Abstract

A simplified method for the determination of aldicarb and its oxidation products, aldicarb sulfoxide, and aldicarb sulfone, in water has been developed. Aldicarb and its metabolites are adsorbed on Amberlite XAD-2 polymer resin and then eluted with acetone. The eluate is analyzed for aldicarb and aldicarb sulfoxide by high performance liquid chromatography (HPLC) with UV detection at 254 nm. Total aldicarb residues can be determined by a colorimetric method. Typical detection limits in drinking water are 1 μg/1.     

Photochemical-chemiluminometric determination of aldicarb in a fully automated multicommutation based flow-assembly

A sensitive and fully automated method for determination of aldicarb in technical formulations (Temik) and mineral waters is proposed. The automation of the flow-assembly is based on the multicommutation approach, which uses a set of solenoid valves acting as independent switchers. The operating cycle for obtaining a typical analytical transient signal can be easily programmed by means of a home-made software running in the Windows environment. The manifold is provided with a photoreactor consisting of a 150 cm long × 0.8 mm i.d. piece of PTFE tubing coiled around a 20 W low-pressure mercury lamp. The determination of aldicarb is performed on the basis of the iron(III) catalytic mineralization of the pesticide by UV irradiation (150 s), and the chemiluminescent (CL) behavior of the photodegradated pesticide in presence of potassium permanganate and quinine sulphate as sensitizer. UV irradiation of aldicarb turns the very week chemiluminescent pesticide into a strongly chemiluminescent photoproduct. The method is linear over the range 2.2-100.0 μg l⁻¹ of aldicarb; the limit of detection is 0.069 μg l⁻¹; the reproducibility (as the R.S.D. of 20 peaks of a 24 μg l⁻¹ solution) is 3.7% and the sample throughput is 17 h⁻¹.     

Transformation Studies of Some Polar Pesticides In Water By On-Line Solid-Phase Extraction and Liquid Chromatography/Particle Beam-Mass Spectrometry

ABSTRACT

An on-line automated method for phototransformation studies of alachlor, aldicarb, and methiocarb by means of liquid chromatography/mass spectrometry (LC/MS) with particle beam (PB) interface is described. Surface water samples were first spiked with 50 μg/1 of each pesticide and then exposed to the radiation of a medium-pressure mercury lamp. Next, in regular intervals of 60 min, aliquots of 50-ml sample were enriched on a solid-phase extraction (SPE) cartridge and on-line eluted by a gradient of LC eluent onto analytical column for separation, followed by MS detection. A phototransformation experiment with each pesticide was performed twice, with MS operated in electron ionisation (EI) and positive chemical ionisation (PCI) modes. Many transformation products (TPs) of parent pesticides were detected and in numerous instances, tentatively identified. Appearance of several transformation products is reported for the first time.     

Separation of aldicarb,aldicarb sulfoxide,and aldicarb sulfone on unmodified silica with reverse-phase eluents

Summary Aldicarb, aldicarb sulfoxide, and aldicarb sulfone were chromatographed on an octyl-silica bonded-phase column and on an unmodified silica column using acetonitrile/water mobile phases. The elution order of the analytes from the silica column was different from that using the octyl-silica bonded phase and allowed confirmation of residues of aldicarb sulfoxide in citrus nectar. Isocratic elution of the unmodified silica column allowed rapid sample throughput.     

Identification of degraded products of aldicarb due to the catalytic behavior of titanium dioxide/polyacrylonitrile nanofiber

Photocatalytic properties of fibers containing TiO₂ nanoparticles were explored for use as a self-decontaminating material using degradation of the pesticide aldicarb as the model toxin. During the analysis of the aldicarb treated sample by liquid chromatography (LC) with diode array detector (DAD), an unidentified peak was found at relative retention time (RT) 3.9 min when compared to aldicarb and major metabolites, aldicarb sulfoxide, and aldicarb sulfone. An analytical method was developed to confirm and identify this degradation product. LC–APCI/MS techniques were used first to analyze molecular ions and major fragments comparing retention times and spectra with those of known standards. FTIR and LC–MS/MS techniques were used to confirm the identity of the degradation product as 2-propenal, 2-methyl-, O-[(methylamino)carbonyl]oxime.