Paper-based chromatographic chemiluminescence chip for the detection of dichlorvos in vegetables

• A paper-based chemiluminescence (CL) analytical device combined with paper chromatography was developed.
• Dichlorvos (DDV) in vegetables can be detected without complicated sample pretreatment on the paper-based device.
• The paper chromatography separation procedure can be accomplished in 12 min on a paper support and the detection limit of DDV was 3.6 ng mL−1.
• Water-soluble metal ions and vitamins cannot interfere the determination of DDV on the paper-based device.

Paper chromatography was a big breakthrough in the early of 20th century but it is rarely used due to the long separation time and the diffusion on the sample spots. In this work, for the first time, a paper-based chemiluminescence (CL) analytical device combined with paper chromatography was developed for the determination of dichlorvos (DDV) in vegetables without complicated sample pretreatment. The paper chromatography separation procedure can be accomplished in 12 min on a paper support (0.8×7.0 cm2) by using 5 µL sample spotted on it. After sample developing, the detection area (0.8×1.0 cm2) was cut and inserted between two layers of water-impermeable single-sided adhesive tapes. The paper-based chip was made by attaching the middle layer of paper onto the bottom layer. Then it was covered by another tape layer, which was patterned by the cutting method to form a square hole (0.8×1.0 cm2) in it. 10 μL mixed solution of luminol and H2O2 was dropped on the detection area to produce CL. A linear relationship was obtained between the CL intensity and the concentrations of DDV in the range between 10.0 ng mL−1 and 1.0 μg mL−1and the detection limit was 3.6 ng mL−1. Water-soluble metal ions and vitamins can be developed at different spatial locations relative to DDV, eliminating interference with DDV during detection. The paper-based chromatographic chip can be successfully used for the determination of DDV without complicated sample preparation in vegetables. This study should, therefore, be suitable for rapid and sensitive detection of trace levels of organophosphate pesticides in environmental and food samples.