Polyimide Substrates Pre-Treated by Capacitively Coupled Plasma and Coated with Composites of Tetracycline-Imprinted Polymethacrylates and Quantum Dots as Fluorescent Sensors

After optimization of fabrication conditions, the capacitively coupled plasma-treated polyimide (PI) substrates were coated with composites of molecularly imprinted polymers and CdTe quantum dots and used to detect tetracycline (Tc) in the range of 5–3000 μM (R2 = 0.9995) with a LOD of 0.2 μM (S/N = 3, RSD = 2.2% at 5 μM Tc, n = 10) by using a fluorescent quenching effect. The selectivity of the stripped PIs was evaluated by the imprinting factors (IFs) for Tc (IF = 7.2), other Tc analogues (IF = 3.4–5.3), and steroids (IF ≈ 1) and by the recoveries of 5 μM Tc from bovine serum albumin at 300 μg/mL (98%, RSD = 3.2%, n = 5), fetal bovine serum at 1.5 ppt (98%, RSD = 2.8%, n = 5), and liquid milk (94.5%, RSD = 5.3%, n = 5).