Determination of four sulfonamides residues in prawn by ultrasound-assisted matrix solid phase dispersive extraction combined with pre-column derivation high performance liquid chromatography-fluorescence

Objective To establish a method for the simultaneous determination of four sulfonamides residues in prawn, including sulfadiazine, sulfathiazole, sulfamerazine and sulfamethazine, by ultrasound-assisted matrix solid phase dispersion extraction coupled with pre - column derivation high performance liquid chromatography(HPLC). Methods Through the optimization of extraction conditions, ethyl acetate was selected as the extraction agent and florisil as the solid dispersion agent, and the sulfonamides in prawn were extracted with the method ultrasound-assisted matrix solid phase dispersion. The sulfonamides were pre-column derived by fluorescamine and detected by HPLC-fluorescence method. Results All sulfonamides showed good linearity in the concentration range of 2-100μg/L, with the correlation coefficient>0.999. The limit of detection and limit of quantification was 0.5 and 2μg/kg, respectively. The spike recoveries of blank prawn samples were 84.4%-93.9% at two levels of 2 and 20μg/kg, with the relative standard deviation(n =3)less than 7.7%. Conclusion The method is simple, time-consuming and high precision, which meets the requirements of residue analysis

Effect of Au@MoS2 Contacted PEDOT:PSS on Work Function of Planar Silicon Hybrid Solar Cells

Abstract Solar cells formed by spin‐coating organic absorber layers on silicon have attracted widespread attention due to their simple processes and high photovoltaic conversion efficiency (PCE). In typical organic/Si solar cells, however, surface defects or unsatisfactory carrier separation are inadequate to yield excellent device performance. Here, the Au@MoS2 nanocomposites are well synthesized and doped into the organic layer of poly (3,4‐ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) to improve its work function and the performance of PEDOT:PSS/Si HSCs consequently. By optimizing the doping level of Au@MoS2, the PCE significantly improved from 11.48% to 14.0% by tuning the work function of the PEDOT:PSS layer to more appropriate values. The calculated results based on the Mott–Schottky model indicate that the built‐in field in the PEDOT:PSS/Si interface of HSCs is significantly enhanced due to the increase of work function by the PEDOT:PSS thin films. The enhancement of the built‐in field results in the reduction of the electron–hole recombination loss effectively. The work provides a feasible method for preparing high‐performance PEDOT:PSS/Si HSCs