Conventional

Conventional Calibration is a widely used GPC technique that employs a single  concentration detector, typically a Refractive Index (RI) Detector or UV/VIS to  obtain a relative molecular weight.

The process of conventional calibration is as follows:

Inject a series of narrow polymer or protein standards of known molecular  weight.

Measure the retention volume (RV) of the resulting peak apex.

Construct a calibration curve of Log(MW) vs. RV

The advantages of conventional calibration are simplicity of equipment and hence the capital cost.

The disadvantage is that it needs to be routinely repeated (which we all forget to do) and the standards used are not the same molecular shape as your species of interest so there are errors.