Hi =)

I have two Q's

1. What are the 2 purposes of using a caffine standard during the HPLC process?

In general not talking about HPLC I would think a standard is for
a)comparing to your own results to see how good your results came out.
b) seeing if you have any contamination in your sample which would show when you compare your results to the standard.

~not sure how correct those two are since to me it seems like I'm trying to pass one reason as 2...can anyone help me with those?

2. What is a Isocratic Solvent system??? (relates to HPLC)

mobile phase is 50/50 methanol: buffered water (pH3), detector set to 254nm, flow rate~1-2ml/min

Thanks.