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Chemical protection of plants against herbivory is a well-studied phenomenon. However, chemical protection of floral rewards remains relatively unexplored. As with herbivore-plant interactions, toxic rewards may impact generalist and specialist foragers in different ways., This study focuses on the toxic plant Aconitum septentrionale (Ranunculaceae). This plant is visited by specialist and generalist bumblebees. Alkaloid concentrations and profiles for the different parts of A. septentrionale were analysed to detect a potential chemical toxicity of floral rewards. In the same way, sequestration of alkaloids was tested on a pollen specialist species Bombus consobrinus and a generalist species Bombus wurflenii., A liquid chromatography-quadrupole time-of-flight mass spectrometry method was developed to discriminate 16 major compounds in the plant. These alkaloids were present in all parts of the plant, but in different ratios. The concentration was high in the roots but also in pollen, providing evidence of chemical protection of this reward. By contrast, nectar had the lowest concentration of alkaloids. Only six alkaloids were detected in B. consobrinus tissues, at trace levels. For the generalist bumblebee B. wurflenii, no traces of alkaloids were detected., Lappaconitine was the major alkaloid compound in pollen, nectar and B. consobrinus tissues. Low accumulation of alkaloids in B. consobrinus tissues could be an ecological advantage for this specialist species in terms of pathogen and predatory avoidance. [ABSTRACT FROM AUTHOR]

Entomotoxicology studies the application of toxicological analysis on necrophageous insects present on human remains. This paper describes the development and validation of a sensitive liquid chromatography tandem mass spectrometry method for quantification of methadone and its main metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), in developmental stages of Lucilia sericata. One single larva was pulverized in a disposable vial and then extracted with 1-chlorobutane. After evaporation of the organic layer, samples were reconstituted in the mobile phase. Chromatographic separation was achieved on a NUCLEODUR Sphinx RP column with a liquid chromatographic gradient (0.1% formic acid and methanol), ensuring the elution of methadone and EDDP within 15 min. The method was fully validated according to international guidelines. The use of liquid liquid extraction was demonstrated to be effective (matrix effect < 27% and recovery > 66%). The method was linear over the dynamic range (10-400 pg/mg larva) with excellent within- and between-run precision and bias (CV% < 5%). The lower limit of quantification was fixed at 10 pg/mg larva. No instability of the extracted samples was observed in the autosampler after three freeze/thaw cycles and after two months at -20 degrees C. The validated method was applied to third instar larvae of Lucilia sericata reared on beef heart spiked with 4 microg/g methadone and on a postmortem methadone overdose case. The validation and actual sample analysis showed that the method is sensitive, rugged, precise, accurate, and well-suited for routine analysis of methadone and EDDP in a single larva obtained from forensic cases.

A simple, rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry method was developed and fully validated for the quantitative determination of seven amphetamines and metabolites in urine. The method was validated for selectivity, linearity, LOQ, LOD, imprecision, bias, analyte and processed sample stability, matrix effect, recovery, carryover and dilution integrity. A classic liquid-liquid extraction with ethyl acetate was used as sample preparation procedure. The compounds were separated on an Acquity UPLC HSS C18 column in 6.8 min. The linear dynamic range was established from 25 to 500 ng/mL. The limit of quantification was fixed to the lowest calibrator level and the limit of detection ranged from 0.125 to 2.5 ng/mL. The method presented an excellent intra- and inter-assay imprecision and bias (<10.7%) at each measured concentration of two external quality controls (QC) and three "in house" QC. No matrix effects were observed and good recoveries (>70%) were obtained for all the compounds. No carryover was observed after the analysis of high concentrated samples (8000 ng/mL). The method was subsequently applied to authentic samples., (Copyright 2010 Elsevier B.V. All rights reserved.)