Determination of chlorpyrifos in air, leaves and soil from a greenhouse by gas-chromatography with nitrogen–phosphorus detection, high-performance liquid chromatography and capillary electrophoresis X. Guardinoa, *, J. Obiolsa, M. G. Rosella, A. Farranb and C. Serrab Journal of Chromatography A Volume 823, Issues 1-2, 9 October 1998, Pages 91-96