Abstract:

This paper reports on a convenient and rapid method for the detection of melamine in food samples by lateral
flow strip technology. The method is based on competitive immunoreaction. The traditional test strip was made much more
sensitive by adding an enhancement pad. For the melamine lateral flow strip, 25 nm and 15 nm colloidal gold nanoparticles
were adopted in the recognition and enhancement pads, respectively. The results showed that detection of melamine in food
samples could be achieved in less than 10 min. The limit of detection (LOD) of the enhanced lateral flow strip was 0.5 μg/L
under our experimental conditions, which showed a 20-fold increase over 10 μg/L for the traditional lateral flow strip. This
new method was able to detect 0.1–5 μg/L melamine in real samples and the sensitivity was 1 μg/L, indicating a 5-fold
increase over that of the traditional one.

Key words: colloidal gold nanoparticle, melamine detection, lateral flow strip, signal amplification