Optional extension for SEC/GPC data evaluation. Date: 3.11.2009. Code: P002/28A. 2. GPC Extension. GPC mode. Date: 3.11.2009. Code: P002/28A. 3. GPC Instrument Type. GPC / Standard mode switching. GPC mode method tabs. GPC Instrument is configured in System Configuration windowGPC or Standard mode can be selected on GPC Instrument Chromatograms can be evaluated alternatively in both modes .