I´m looking for a simple way of measuring the peptide concentration of a solution. The solution contains a micro- to millimolar concentrations of a 8, 9 or 10-mer peptide. These peptides do not contain Trp or Tyr, therefore diluting in 6M guanidine and measuring th OD at 280 nm will not work. Is there an alternative to HPLC ? Regards, Andy Johnston. ---