Magnetic polyimide nanosheet strings for determination of anabolic androgenic steroids in tap-water, functional drink, and external drug by magnetic solid-phase extraction combined with gas chromatography–mass spectrometry

Abstract

Magnetic polyimide (PI) nanosheet strings were prepared by wrapping PI nanosheets around the γ-Fe2O3 nanowires. The γ-Fe2O3/PIs composite was successfully used for magnetic solid-phase extraction (MSPE) of anabolic androgenic steroids (AASs). The γ-Fe2O3/PIs composite possessed adequate saturation magnetic strength (8.7 emu/g) from inner γ-Fe2O3 nanowires, and large specific surface area (154.1 m2/g) for high adsorption capacity (≥ 8.9 μg/mg for selected 9 AASs) from outer PI nanosheets. Subsequently, trace AASs in water were extracted by γ-Fe2O3/PIs and determined by gas chromatography–mass spectrometry (GC-MS) after desorption and derivatization. Under the optimized extraction and desorption conditions, the MSPE of AASs based on γ-Fe2O3/PIs was established. For purified water, the linear range was 0.01–100, 0.02–100, 0.05–100, 0.1–100 or 0.2–100 μg/L with determination coefficients (R2) greater than 0.9950. The recoveries ranged from 78.3% to 115.7%, with relative standard deviations (RSDs) between 1.9 and 11.8%. The limits of detection (LODs) were in the range of 0.0025–0.046 μg/L. For the three real samples, tap-water, functional drink, and external analgesic aerosol drug, the recoveries were 68.8–119.0%, and the corresponding RSDs were 0.4–11.0%. This study provides a new strategy for the preparation of magnetic adsorption materials and an alternative method for the detection of pollutants in aqueous samples.