I am currently working on Calibrating a HP 6890 Series GC. I am newer to GC (limited to college experience). I ran close to 20 solvents for my full calibration. Used a series of four for each solvent ranging from 1mL to 10mL. Majority of my solvents came out well and had good calibration curves. However, for two sets of solvents Isopropanol/Ethanol, and Toluene/Normal Propyl alcohol I am having separation issues. I attempted to change the temperature ramping, pressure flows, and even switched the detectors, but with my limited knowledge and not wanting to toy around with too many parts I am unsure what to try next. Thought about switching the column which is currently a 112-2032 J&W Carbowax/20m but again unsure due to previous statement. Looking for some advice or just knowledge to help me out.