Development of a highly sensitive colloidal gold semiquantitative method for the determination of difenoconazole residues in citrus

Abstract

IntroductionDifenoconazole (DIFE) is a common pesticide used in citrus cultivation; excessive intake can cause neurological damage to the organism, and the existing colloidal gold immunochromatographic test strips cannot meet the requirements for the detection of citrus samples.MethodsDifenoconazole test strip was prepared based on the colloidal gold immunochromatographic technique (GICT), and its application in citrus samples was investigated; with colloidal gold (CG) as the probe, the optimization of GICT parameters, and the determination of reaction method, the immunochromatographic test strips for the detection of DIFE in citrus was developed, and the limit of detection (LOD), specificity, accuracy, and stability of the test strips were verified.ResultsThe results showed that the visual detection limit of the prepared colloidal gold immunochromatographic test strips was 0.2 mg/kg and the quantitative range was 0.06–0.6 mg/kg, and the test strips could specifically identify DIFE and have no cross-reaction with other common triazole pesticides. The detection method established in this study was verified by the GC–MS method, and the detection results achieved good consistency (R2 > 0.98).ConclusionThe test strips developed in this study have good performance and can be used for highly sensitive detection of citrus samples.

Colorimetric detection of the potent carcinogen aflatoxin B1 based on the aggregation of L-lysine-functionalized gold nanoparticles in the presence of copper ions

“…Both the shape and position of the absorption band can be associated with 0-dimensional nanostructures with a spherical morphology ( 14 ). These results are in close agreement with the findings reported by Wang et al ( 15 ) who stated that AuNPs synthesized using sodium citrate show a distinctive plasmon around 524 nm. Nanoparticle formation can also be tracked through the solution’s color shift, from colorless right after the addition of sodium citrate to a bright ruby-red shade when the reaction finishes.…”