Help with Epilactose separation

[inaira]

Hello, it's my first time here.

I have a Shodex VG-50 4E HPLC column, which I want to use to measure epilactose, lactulose, and lactose. According to the manual, the mobile phase should consist of 75% acetonitrile, 20% methanol, and 5% water, with a column temperature of 40°C and a flow rate of 1 mL/min. However, I am not detecting the analytes, even when using standard samples.

I am working with a Jasco HPLC system equipped with an RI-4030 refractive index detector. What could be causing this issue?
In other laboratory with the same colum and same HPLC model it works well.

[itspip]

My first thought is that the detector might be the issue. You say that the same column and analytes in a different, but equivalent, system works. I would first try to purge the reference cell of the RID and see if that helps.