Abstract
•Polymeric sorbent β-cyclodextrin (β-CD) was used in micro-solid phase extraction (μ-SPE) for the first time in steroid profile analysis.•Factors that affect extraction performance were suitably optimized.•This method provided good linear range and comparable limits of detection to conventional method.•The μ-SPE technique possess numerous features of green analytical chemistry (simple, rapid), markedly reduced consumption of samples and solvents.
Sorbents were prepared by cross-linking β-cyclodextrin (β-CD) using two different types of cross-linker units at variable reactant mole ratios. The resulting polymers containing β-CD were evaluated as sorbents in micro-solid phase extraction (μ-SPE) format for the extraction of the endogenous steroids testosterone (T), epitestosterone (E), androsterone (A), etiocholanolone (Etio), 5α-androstane-3α,17β-diol (5αAdiol) and 5β-androstane-3α,17β-diol (5βAdiol). The best sorbent (C1; cyclodextrin polymer) showed superior extraction characteristics compared with commercial sorbents (C18 and Bond Elut Plexa). Parameters influencing the extraction efficiency of the C1 sorbent such as extraction and desorption times, desorption solvent and volume of sample were investigated. The extracts were separated using a Hypersil Gold column (50 × 2.1 mm, 1.9 μm) under gradient elution coupled to a LC–MS/MS. The compounds were successfully separated within 8 min. The method offers good repeatability (RSD < 10%) and linearity (r2 > 0.995) were within the range of 1–200 ng mL−1 for T and E, 250–4000 ng mL−1 for A and Etio and 25–500 ng mL−1 for 5αAdiol and 5βAdiol, respectively. The method was applied for the determination of steroid profile of urine from volunteers.