Identifying the metabolic perturbations in earthworm induced by cypermethrin using gas chromatography-mass spectrometry based metabolomics.

Globally, cypermethrin is one of the most widely used synthetic pyrethroid for agricultural and domestic purposes. Most part of the pesticides used in the agriculture ends up as residues in the soil, making soil dwelling organisms, especially earthworms more susceptible to pesticide intoxication. Cypermethrin is known to be a neurotoxicant to many model organisms, including mammals and insects, but such type of toxicity evidence is not available for invertebrate systems like earthworms. In the present work, metabolomics based approach was utilized to identify the toxic mechanism of action of cypermethrin on earthworm (Metaphire posthuma) and these were exposed to sub-lethal concentrations of cypermethrin such as 2.5 mg/kg, 5 mg/kg, 10 mg/kg and 20 mg/kg (1/40(th), 1/20(th), 1/10(th) and 1/5(th) of LC50, respectively) for fourteen days. The results revealed that 22 metabolites (mainly fatty acids, sugars and amino acids) were shown significant responses in the exposed earthworms and these responses are dose dependent. It is proposed that mainly carbohydrate and fatty acids in neural system metabolism was disturbed. Overall, the results provided that metabolomics can be an effective tool to understand the effects of cypermethrin on the metabolic responses of earthworm Metaphire posthuma.

Imprinted nanospheres based on precipitation polymerization for the simultaneous extraction of six urinary benzene metabolites from urine followed by injector port silylation and gas chromatography-tandem mass spectrometric analysis.

In the present communication, uniformly sized molecularly imprinted polymer (MIP) as nanospheres were synthesized based on precipitation polymerization using dual-template imprinting approach and used it as sorbent for solid phase extraction of six urinary benzene metabolites (UBMs). This approach in combination with injector port silylation (IPS) has been used for the quantitative determination of these UBMs by gas chromatography-tandem mass spectrometry. The MIP was synthesized by using t,t-muconic acid (t,t-MA) and 1,2,4-trihydroxybenzene (THB) as templates, methacrylic acid (MAA) as a monomer, ethyleneglycoldimethacrylate (EGDMA) as crosslinker, acetonitrile and dimethylsulphoxide as a porogen and azobisisobutyronitrile (AIBN) as an initiator. The factors affecting the performance of polymer and IPS were investigated and optimized for the simultaneous determination of UBMs in urine. Binding study of imprinted and non-imprinted polymer (NIP) shows that, MIP possesses higher affinity in comparison to NIP for these analytes. Under the optimum conditions, the method developed was found to be linear with regression coefficients falls in the range of 0.9721-0.9988 for all the analyzed metabolites. The percent recovery of the metabolites analyzed in urine was found to be in the range of 76-89%, while the limit of detection and limit of quantification were found to be in the range of 0.9-9.1ngmL(-1) and 2.8-27ngmL(-1) respectively. The validated method was successfully applied to the real urine samples collected from different groups (kitchen workers, smokers and petroleum workers) and found that the developed method has been promising applications in the routine analysis of urine samples of benzene exposed population.