Application of single-drop microextraction and comparison with solid-phase microextraction and solid-phase extraction for the determination of α- and β-endosulfan in water samples by gas chromatography-electron-capture detection

1. López-Blanco, M.C.
2. Blanco-Cid, S.
3. Cancho-Grande, B.
4. Simal-Gándara, J.