For parent pesticides analysis xA mL of phosphate buffer

3. Results and discussions
3.1. Method development
3.1.1. Parent AMD-070 and pesticide metabolites in hair
Because of the limited amount of sample generally available with hair, the decision was made to analyze parent pesticides and their metabolites on the same hair strand and using a single extraction. A split of the extract was thereafter necessary because the derivatization step of the metabolites induced degradation of some parent compounds (due to high temperature) and increased the background noise.
The main difficulty lay in finding the most appropriate solvent to extract compounds because of their difference in terms of hydrophobicity and polarity. Different extraction solvents (acetonitrile, methanol, acetonitrile–water, acetonitrile–methanol or acetonitrile–methanol–water) were therefore tested. As presented in Fig. 1, the best accommodation was observed with a mix of acetonitrile–water (80:20, v/v) to extract a maximum of analytes.
Fig. 1. Efficiency of different solvents for the extraction of parent pesticides and metabolites from supplemented hair sample at 20 or 200 pg/mg (n = 5). Results are expressed as normalized areas. ACN, acetonitrile; MeOH, methanol.Figure optionsDownload full-size imageDownload high-quality image (280 K)Download as PowerPoint slide