Hi, I'm going to separate PSSs STD mixture(PSS MW 16500,8890,5580,1690) with HPLC SEC column(jaigel gs310).

I prepared the STD mix by mixing each of the standard substances at about 10 mg/L in a 1:1:1:1 ratio.

but, Looking at the results, it seems that there was no separation.

1) What is the cause and what is the solution?

method

buffer : DI 40℃ 0.5ml/min 2.7MPa run time 80min sample : STD mixture