Fig 1.
Schematic diagrams illustrating the principle of (a) localized surface plasmon resonance and (b) the optical fiber-based LSPR biosensing system.
Fig 2.
(a) Mechanism of the colorimetric detection of melamine based on the unmodified AuNPs; (b) UV-Visible absorption spectra of AuNPs (blank), AuNPs+0.5μM melamine and AuNPs+2μM melamine.
Fig 3.
TEM images of the citrate-stabilized AuNPs, AuNPs+0.5μM melamine and AuNPs+2μM melamine.
Fig 4.
UV-Visible absorption spectra of AuNPs added with different concentrations of melamine (0, 0.05, 0.2, 0.4, 0.6, and 0.9 μM) and the calibration curve of melamine detection (inset).
Table 1.
Comparison of the detection limits of the various methods in the colorimetric detection of melamine in milk.
Fig 5.
Specificity of the AuNPs for melamine detection, compared with other interfering compounds in liquid milk.
Table 2.
The obtained recovery rate from measurement results.