The fabrication of a -SPE device was as described previously [25]. Each device was made by packing 4 mg of MWCNTs in a (1.0 cm × 0.8 cm) porous polypropylene membrane with heatsealed edges.
The fabrication of a -SPE device was as described previously[25]. Each device was made by packing 4 mg of MWCNTsin a (1.0 cm × 0.8 cm) porous polypropylene membrane with heatsealed edges.