Biomass-derived carbon nanospheres decorated by manganese oxide nanosheets, intercalated into polypyrrole, as an inside-needle capillary adsorption trap sorbent for the analysis of linear alkylbenzenes

Abstract

Carbon nanospheres (CNSs) were derived hydrothermally from biomass (orange peels) and decorated by manganese dioxide (MnO2) nanosheets. The MnO2/CNSs nanocomposite was intercalated into polypyrrole (PPy) during flow-through in-situ electropolymerization of pyrrole on the surface of the inner wall of a stainless-steel needle to prepare an inside-needle capillary adsorption trap (INCAT) device. The surface morphology, thermogravimetric behavior, sorption characteristics, and structure of the MnO2/CNSs@PPy nanocomposite were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), nitrogen physisorption by the Brunauer-Emmett-Teller (BET) method, dynamic light scattering (DLS) size distribution, and Fourier-transform infrared spectrometry (FT-IR). The INCAT device was coupled with GC-FID and applied for dynamic headspace analysis of linear alkyl benzenes (LABs) in wastewater samples. The effective experimental variables on the extraction efficiency was optimized using a central composite design (CCD) based on response surface methodology (RSM). Under the optimal conditions, the limits of detection (LODs) were in the range of 0.5–1.0 ng mL−1. The calibration plots were linear over the range of 0.01–10 μg mL−1. The relative standard deviations (RSDs%) for intra-day, inter-day, and inter-INCAT precision were calculated 5.3–8.3%, 9.4–13.5%, and 13.6–16.9%, respectively. The developed technique was employed successfully for the analysis of LABs in water and wastewater samples with average recovery values ranging from 92 to 109%. A single INCAT device was used more than 90 times without significant change in its extraction capability.