Simultaneous detection of multiple chemical residues in milk using broad-specificity antibodies in a hybrid immunosorbent assay.
In this study, a novel immunoassay using 2 types of sensors (QDs and an enzyme) were simultaneously used for detecting multiple structurally different molecules in milk. The method integrates the fluorescence-linked immunosorbent assay (FLISA) using QD605 and QD655 as probes and an enzyme-linked immunosorbent assay (ELISA) using horseradish peroxidase (HRP) labeled secondary antibody. The FLISA was produced by anti-sulfonamide and anti-quinolone broad-specificity monoclonal antibodies (MAbs) for simultaneously detecting 6 sulfonamides and 11 quinolones. Combined with the FLISA, an ELISA was utilized for detecting melamine from the same milk samples. The cross-reactivity of the MAbs was retained while binding the QDs by using avidin and a secondary antibody as bridges. Milk samples were detected using this hybrid immunoassay, with limits of detection (LOD) of the quinolones (0.18 ng mL(-1)), sulfonamides (0.17 ng mL(-1)) and melamine (7.5 ng mL(-1)), respectively. The results demonstrated that the detection limits of the integrated methods were better than required and simplified the sample pretreatment process. The developed immunoassay is suitable for high-throughput screening of low-molecular weight contaminants.
National Reference Laboratory for Residues of Veterinary Drugs, Beijing 100193, China.
Kui
K
Zhu
Jiancheng
J
Li
Zhanhui
Z
Wang
Haiyang
H
Jiang
Ross C
RC
Beier
Fei
F
Xu
Jianzhong
J
Shen
Shuangyang
S
Ding
D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*