ALIGNED ELECTROSPUN POLY(VINYL ALCOHOL) NANOFIBERS FOR ULTRATHIN LAYER CHROMATOGRAPHY

Abstract

Aligned electrospun poly(vinyl alcohol) nanofibers (AE-PVA) were fabricated by electrospinning technique and applied as a stationary phase for ultrathin layer chromatography (UTLC). Because PVA is soluble in water, this is a limitation for using AE-PVA as a stationary phase. To enhance the stability in water, PVA was crosslinked by glutaraldehyde for 5 h before electrospinning process. The AE-PVA nanofibers generated at the electrospinning condition as follow; high voltage of 24 kV, solution flow rate of 7 mL/min, collector distance of 15 cm and rotational speed of collector of 1250 rpm, provided the most satisfied nanofibers in term of morphology and alignment of fibers. The average diameter of AE-PVA fibers at this condition was 459±71 nm and 65% of fibers were aligned within 5o angle from the virtual line. For separation performance, the mobile phase transport on the AE-PVA UTLC was fitted the Lucas-Washburn equation which was referred that the transport of mobile phase was mainly based on capillary flow through porous media similar to that on conventional silica TLC. Moreover, the migration of mobile phase on AE-PVA UTLC was more rapid than that on E-PVA UTLC and silica TLC as the velocity constant of AE-PVA UTLC was 0.0985 cm2/s which was twice higher than that of E-PVA which was 0.0448 cm2/s and 6 times higher than that of silica fibers UTLC which was 0.019 cm2/s. Finally, the analysis of amino acids was performed using AE-PVA UTLC and compared to E-PVA UTLC and silica TLC. The separation efficiency of AE-PVA UTLC which was demonstrated by the plate number and plate height was comparable with silica TLC but less efficient than E-PVA which caused by shape and size of sample spot on the plate. However, the analysis time of AE-PVA UTLC was greatly decrease by the factor of 4-5 times comparing with E-PVA and silica TLC.