Enhancing hydrogel-based long-lasting chemiluminescence by a platinum-metal organic framework and its application in array detection of pesticides and d-amino acids†
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 H2O2. 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.