Trace-level determination of pyrethroid, neonicotinoid and carboxamide pesticides in beeswax using dispersive solid-phase extraction followed by ultra-high-performance liquid chromatography-tandem mass spectrometry

<div><p>The aim of the work was to develop an analytical procedure able to quantify traces of 13 neonicotinoids and pyrethroids as well as carboxamide in beeswax at low levels (ng g⁻¹) to evaluate the contamination. For this purpose, an efficient sample preparation procedure was developed based on solid–liquid extraction using dispersive diatomaceous earth and acetonitrile. This step was followed by a selective and sensitive analysis based on ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (ESI-MS/MS). This analytical procedure was validated based on International Conference on Harmonization guidelines. The limits of quantification ranged from 1 ng g⁻¹ (thiamethoxam, clothianidin, imidacloprid, acetamiprid, thiacloprid and boscalid) to 40 ng g⁻¹ (lambda-cyhalothrin). The method was then successfully applied to 60 samples of beeswax collected in several areas of France. The presence of thiacloprid, boscalid, imidacloprid and deltamethrin in beeswax was confirmed. The most frequently quantified pesticide was boscalid.</p></div

Intensities of internal standard metabolites (normalized to the maximal response) analyzed by LC(RPLC)-(ESI+)- or LC(HILIC)-(ESI-)- HRMS after extraction of 50 mg or 25 mg of brain with 2.5 mL or 7 mL of MeOH/H₂O/heptane.

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Intensities of internal standard metabolites (normalized to the maximal response) analyzed by LC(RPLC)-(ESI+)- or LC(HILIC)-(ESI-)- HRMS after extraction of 50 mg of brain with 2.5 mL of different proportions of MeOH/H₂O /heptane.

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Venn diagram showing specific and overlapping of detected features (m/z, R_T) achieved with the RPLC(ESI+)/HILIC(ESI-) analyses in brain, gills, liver and fish (expressed in % of total features).

Venn diagram showing specific and overlapping of detected features (m/z, RT) achieved with the RPLC(ESI+)/HILIC(ESI-) analyses in brain, gills, liver and fish (expressed in % of total features).</p

Intensities of targeted metabolites analyzed in LC(RPLC)-(ESI+/-)-HRMS conditions with MeOH or ACN as organic mobile phase B, after extraction of 50 mg of fish spiked at 500 μg/L.

Intensities of targeted metabolites analyzed in LC(RPLC)-(ESI+/-)-HRMS conditions with MeOH or ACN as organic mobile phase B, after extraction of 50 mg of fish spiked at 500 μg/L.</p

Fig 7 -

Intensities of targeted metabolites detected in fish, liver, brain and gills, analyzed in (a) RPLC(ESI+) and (b) HILIC(ESI-).</p

Number of features (m/z, R_T) detected with different sample mass and volume of the extraction solvents in fish, liver, brain or gills, analyzed in LC(RPLC)-(ESI+) and LC(HILIC)-(ESI-) HRMS.

Number of features (m/z, RT) detected with different sample mass and volume of the extraction solvents in fish, liver, brain or gills, analyzed in LC(RPLC)-(ESI+) and LC(HILIC)-(ESI-) HRMS.</p

Intensities of internal standard metabolites (normalized to the maximal response) analyzed by LC(RPLC)-(ESI+)- or LC(HILIC)-(ESI-)- HRMS after extraction of 50 mg of liver with 2.5 mL of different proportions of MeOH/H₂O /heptane.

(PDF)</p

Intensities of internal standard metabolites (normalized to the maximal response) analyzed by LC(RPLC)-(ESI+)- or LC(HILIC)-(ESI-)- HRMS after extraction of 50 mg or 25 mg of liver with 2.5 mL or 7 mL of MeOH/H₂O/heptane.

(PDF)</p

Intensities of internal standard metabolites (normalized to the maximal response) analyzed by LC(RPLC)-(ESI+)- or LC(HILIC)-(ESI-)- HRMS after extraction of 25 mg of gills with 2.5 mL of different proportions of MeOH/H₂O /heptane.

(PDF)</p