Imidacloprid water samples

The determination procedure is described in Section 2.2.4. The ELISA determination of water samples can be performed directly, such as for imidacloprid in tap water. ... 

The LODs for imidacloprid and metabolites, when determined by US Environmental Protection Agency (EPA) guidelines, are 0.021-0.024 ngL The LOQ is defined as 0.1 ng for each metabolite. Recoveries from control water samples fortified at the 0.1 and 1 ngL levels ranged between 84 and 107% for all metabolites. No relative standard deviation between the respective recoveries for any of the analytes was greater than 10%. 

Zhou, Q., Y. Ding, and J. Xiao. 2006. Sensitive determination of thiamethoxam, imidacloprid and acet-amiprid in environmental water samples with sohd-phase extraction packed with multiwalled carbon nanotubes prior to high-performance hquid chromatography. Anal. Bioanal. Chem. 386 1520-1525. 

Alba et al. used ethyl acetate to extract imidacloprid residues from fruits and vegetables. A 15-g sample of vegetable or fruit is weighed into a blender tube and 60 mL of ethyl acetate and 15g of sodium sulfate are added. The mixture is homogenized for 30 s, using a Polytron, and filtered. The filtrate is evaporated and the residue obtained is dissolved in acetonitrile-water (1 1, v/v). Alba etal. considered the low recoveries of these polar pesticides as the major disadvantage of the acetone extraction method. In their previous work they evaluated the efficacy of ethyl acetate for the extraction of pesticide residues. 

Enzyme-linked immunosorbent assay (ELISA). Li and Li developed an ELISA procedure for imidacloprid to determine its residues in coffee cherry and bean extracts. A 25-g amount of sample extracted with 300 mL of methanol and 1% sulfuric acid (3 1, v/v) for 3 min. An aliquot of the sample extract (0.5 mL) is mixed with 1 mL of water and a gentle stream of nitrogen is used to evaporate methanol. The solution is then extracted with 1 mL of ethyl acetate, the extract is reconstituted in 1 mL of PBST (phosphate-buffered saline containing 0.05% Tween 20) and competitive ELISA is performed to quantify imidacloprid in the extract. Eor methanol extracts of coffee cherries and beans fortified with imidacloprid at 0.5 mgL recoveries of imidacloprid by the ELISA method were 108 and 94, respectively. 

The extraction method for imidacloprid residues has been presented by Westwood et al. A 20-g soil sample is extracted with 20 mL of acetonitrile-water (4 1, v/v) by... 

The anionic surfactant sodium dodecylsulfate (SDS) is by far the most commonly used surfactant in micellar separations. Examples of the use of simple buffered/SDS systems in environmental applications include the simultaneous analysis of 10 A-methylcarbamate pesticides and their hydrolytic phenolic metabolites in river, well, and pond water (pH 8 phosphate/borate buffer/SDS), and the analysis of insecticides (imidacloprid and its metabolite 6-chloronicotinic acid) in air samples collected from a greenhouse cropped with tomatoes (pH 8.5 ammonium chloride/ammonia buffer/SDS). ... 

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