Enhancing hydrogel-based long-lasting chemiluminescence by a platinum-metal organic framework and its application in array detection of pesticides and d-amino acids

Abstract

Organophosphorus pesticides (OPs) are harmful to people's health and D-amino acids (D-AAs) in the human body are closely related to various diseases. So, detection of OPs in foods and D-AAs in serum is important for food safety and clinical diagnosis. Herein, a long-lasting chemiluminescence (CL) imaging sensor was constructed for the detection of OPs and D-AAs. The method was based on N-(4-aminobutyl)-N-ethylisoluminol/Co²⁺/chitosan (ABEI/Co²⁺/CS) hydrogels, where metal organic framework materials (MOF-Pt) were selected as catalysts to improve the sensitivity greatly. Under the catalysis of acetylcholinesterase (AChE) and choline oxidase (CHO), H₂O₂ was produced by using acetylcholine chloride (ACh) as a substrate, which was sensitive to the proposed CL system. OPs inhibited the activity of AChE and decreased the production of H₂O₂, reducing CL intensity. The linear range of the method for chlorpyrifos was 0.5 ng mL⁻¹–1.0 μg mL⁻¹, with a limit of detection (LOD) of 0.21 ng mL⁻¹. Seventeen kinds of OPs can be visually and simultaneously discerned by the CL imager. On the other hand, D-AAs were catalyzed and oxidized by D-α-amino oxidase (DAAO) to produce H₂O_2. Thus, D-Ala in serum was used as a model to be detected by the proposed method. The linear range for D-Ala was 1.0 μM–10 mM, with an LOD of 0.12 μM.