Experimental Study on SERS Enhancement of Gold Colloid

In this paper,the SERS enhancement of gold colloid film and gold colloid solution under the condition of p H= 6 and p H = 13 was studied by using crystal violet( CV) as the probe molecule. Gold colloid solution was prepared using chemical reduction method and its p H value was changed by adding Na OH solution. Gold colloid films were prepared by the self-assembly method. The enhancements of gold colloid film and gold colloid solution with p H = 6 and p H= 13 were evaluated by comparing their enhancement factors( EFs) and the limits of detection( LODs). The EFs of these three substrates were 5. 9 × 103,1. 5 × 105 and 2. 3 × 107 respectively and their LODs of CV were 70. 7 nmol / L,9. 6 nmol / L and 1. 8 nmol / L respectively. The results show that the enhancement of gold colloid solution is better than the gold colloid film. By changing the p H value of gold colloid solution,the aggregation degree and the adsorption properties for adsorbate of gold nanoparticles have been changed as well so that the enhancement of gold colloid solution can be significantly improved.