A microflow chemiluminescence sensor for indirect determination of dibutyl phthalate by hydrolyzing based on biological recognition materials.

A microflow chemiluminescence (CL) sensor for determination of dibutyl phthalate (DBP) based on magnetic molecularly imprinted polymer (MMIP) as recognition element was fabricated. Briefly, a hydrophilic molecularly imprinted polymer layer was produced at the surface of Fe₃O₄@SiO₂ magnetic nanoparticles (MNPs) via combination of molecular imprinting and reversible stimuli responsive hydrogel. In this protocol, the initial step involved co-precipitation of Fe²⁺ and Fe³⁺ in an ammonia solution. Silica was then coated on the Fe₃O₄ nanoparticles using a sol-gel method to obtain silica shell magnetic nanoparticles. The MMIP was synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker and 2,2-azobisisobutyronitrile (AIBN) as initiator in chloroform. Then the synthesized MMIP and magnetic non-molecular imprinted polymers (MNIP) were employed as recognition by packing into lab-made straight shape tubes, connected in CL analyzer for establishing the novel sensor with a single channel syringe pump. And a mixer for hydrolyzing of DBP was followed. Based on this experiment principle, DBP was determined indirectly. And the MMIP showed satisfactory recognition capacity to DBP, resulting to the wide linear range of 3.84 × 10⁻⁸ to 2.08 × 10⁻⁵ M and the low detection limit of 2.09 × 10⁻⁹ M (3σ) for DBP. The relative standard deviation (RSD) for DBP (3.20 × 10⁻⁶ M) was 1.40% (n=11). Besides improving sensitivity and selectivity, the sensor was reusable. The proposed DBP-MMIP-CL sensor has been successfully applied to determine DBP in drink samples.