Toward higher extraction and enrichment factors via a double-reservoirs microfluidic device as a micro-extractive...

In this study, firstly, a double-reservoir and switchable prototype of a micro-chip along with the respective holders were fabricated. A cyclic desorption process using microliter volume of organic solvent was adopted to prevent any outdoor contamination. As extractive phases, two identical sheets of electrospun polyamide/polypyrrole/titania nanofibers were synthesized using core-shell electro-spinning technique and utilized for determination of memantine in plasma samples. Field emission scanning electron microscopy images showed a high degree of porosity and homogeneity throughout the sheet structure. Also, energy dispersive X-ray analysis confirmed the presence of titania, while the recorded Fourier transform infrared spectra proved the chemical structures of the polymeric mats. The incorporation of titania as well as polypyrrole in the composition of polyamide nanofibers improved both mechanical stability and extraction capacity of the extractive phase and therefore facilitated the extraction/desorption process. The limits of detection and quantification were 0.01 and 0.04 ng/mL, respectively. In addition, the interday and intraday precisions were lower than 6.7% (n = 3). The linearity was in the range of 0.14-75.00 ng/mL, while recoveries were between 94.1 and 98.4% with the regression coefficient of 0.9987.