A high-throughput nanofibers mat-based micro-solid phase extraction for the determination of cationic dyes in wastewater.

This study used nanofibers mat (NFsM)-based micro-SPE (μ-SPE) in 96-well plate format as a novel high-throughput sample preparation technique prior to the determination of cationic dyes in wastewater using HPLC-DAD. P-Toluene sulfonate (PTS(-)) doped polypyrrole (PPy) functionalized NFsM (PTS-PPy NFsM) was optimized as SPE sorbent in aspects of PPy form (particles and NFsM) and its doped anions (Cl(-) and PTS(-)), which showed good extraction efficiency and adsorption capacity for cationic dyes (Auramine-O, Chrysoidine and Rhodamine-B). Under the optimal conditions, the limits of detection (LODs) were between 0.3 and 0.5μg/L, and the linearity was achieved in the concentration ranging from 1.0 to 150.0μg/L with correlation coefficients (R) between 0.992 and 0.999. Compared with the published SPE methods, this approach demonstrated its advantages such as shorter extraction time (0.3min per sample), lower requirement sorbent (2.0mg), lower volume of organic solvent (0.7mL), higher recovery (90.1-99.1%) and precision (RSDs<6.9%). With this developed method, we have successfully analyzed the dyeing industry wastewater, which meets the Discharge Standards of Water Pollutants for Dyeing and Finishing of Textile Industry in China. The concentrations of three analyzed cationic dyes were from 2.9 to 13.9μg/L. The NFsM-based μ-SPE technique is practically a high-throughput sample preparation procedure that can accurately assess the pollutants in the wastewater from dyeing industry.