Simultaneous extraction and concentration in carbon nanotube immobilized hollow fiber membranes

Analytical enrichment during continuous hollow fiber membrane extraction involves the movement of analytes from the sample to the extractant. At the same time, a second preconcentration mechanism is provided by out-diffusion of the extracting solvent. These effectively combine extraction and concentration into one step. In this paper, we demonstrate for the first time that the presence of carbon nanotubes (CNTs) can enhance both these phenomenon leading to superior performance in terms of higher enrichment factors and extraction efficiency. The CNTs were immobilized in the pores of a polypropylene hollow fiber and led to nearly 250% enrichment enhancement over the unmodified parent membranes. The detections limits for polycyclic aromatic compounds were between 0.042 and 0.25 microg/L.