I am going to do experiment to study temporal SERS spectrum in a buffer environment that containing Na(+), K(+), Cl(-), HPO4(2-) using adenosine phosphate as analyte and aluminum as SERS substrate.

Study of temporal change of SERS spectrum requires both tightly fixed sample on SERS substrate and also small quantity of sample SERS substrate. while uniformly distributed analyte over SERS substrate is also vital for evaluating enhancement effect.

Thus, I keep on looking for a way to uniformly bind adenosine phosphate on SERS substrate in a tight way in liquid.

So far, what I know is that aminosilane can be used to bind the DNA and RNA, the polymerized product of adenosine phosphate, on the surface oxide of aluminum through the ionic / electrostatic interaction. This can be quite strong that the sample wont move away in liquid during measurement.

However, this seems not to be applicable for the small adenosine phosphate. Also, there seems to be no report about binding adenosine phosphate on substrate with aminosilane.

Thus, may I know if there is any achievable way to bind adenosine phosphate on surface oxide of aluminum through the phosphate part?

Probably a naive idea, but I prefer to bind it through covalent bonding because it wont be affected by ions background in the buffer.

I appreciate any generous comment.