By S T Brumbaugh on Wednesday, July 7, 2004 - 02:12 pm:

I am using an Agilent 1100 with refractive index detector to perform GPC analysis on polybutadiene resins. The mobile phase and sample solvent are THF. Late in the elugram after injection, a negative peak occurs that varies in intensity. This happens with both a sample and a blank THF injection. Has anyone encountered anything similar or does anyone know what is causing this?

Thank you

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By anonymous on Tuesday, July 20, 2004 - 10:05 am:

usually, negative peaks in ri are caused by differences in ri between sample solvent and mobile phase