Simultaneous detection of ofloxacin and lomefloxacin in milk by visualized microplate array

• Published in: Journal of food measurement & characterization 2019-12, Vol.13 (4), p.2637-2643
• Main Authors: Li, Zhoumin, Yao, Kai’an, Li, Xin’ai
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Antibodies; Antigens; Arrays; Calibration; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Engineering; Food Science; Image detection; Immobilization; Immunoassay; Immunoglobulin G; Laboratory equipment; Lomefloxacin; Mathematical analysis; Milk; Nanoparticles; Ofloxacin; Original Paper; Pretreatment; Silver
• ISSN: 2193-4126; 2193-4134
• DOI: 10.1007/s11694-019-00184-7

Analytical method for simultaneous detection of ofloxacin and lomefloxacin in milk by visualized microarray immunoassay without the need of time-consuming or complex pre-treatment steps was reported. A 96-well microplate was used as solid support, in which ofloxacin antigen and lomefloxacin antigen were immobilized, respectively. After immobilization, a mixture of standard solutions containing the analytes or samples and relevant antibodies were added to the array reaction areas, then added silver nanoparticles (AgNPs) labeled secondary antibody (goat anti-mouse IgG). Silver enhancement technique was applied to amplify the detection signals, which produced black image on array spots visible with naked eyes. The signals were detected with a microarray scanner; therefore the analyte residues could detect quantitatively by standard calibration curve. Ofloxacin and lomefloxacin dynamic range were all from 0.05 ng/mL to 12.8 ng/mL. The calibration curve of ofloxacin was calculated as: y = − 0.3446x + 0.4287, r = 0.9849. The calibration curve of lomefloxacin was calculated as: y = − 0.3055x + 0.4797, r = 0.9927. The spike recovery were within 80–130%, and RSD were less than 15%. The limits of detection (LOD) were estimated to be 0.24 ng/mL (ofloxacin) and 0.35 ng/mL (lomefloxacin) (n = 3, 3SD).