Chromatography Forum

I'm excited that it appears I am close to being able to reliably see 10 ppm DRO. Looks like the top of the curve is going to be about 10,000 ppm. Things become distinctly variable higher than that. From one injection to the next a 25,000 can vary 50%. Maybe best culprit is that 0.25um film thickness.

The first column I started out with was 50m and 0.33um film thickness. Too bad it embrittled and fell apart. I can't afford another column at the moment. I'll see how the next month comes out.

Too bad there is not a hack or something to trick the 7673 or 6890 series injectors into doing the solvent saving feature of the newer 7683 model. 3 rinses at 80% of 50uL drains the clean solvent vials remarkably quickly.

Too bad there is not a hack or something to trick the 7673 or 6890 series injectors into doing the solvent saving feature of the newer 7683 model. 3 rinses at 80% of 50uL drains the clean solvent vials remarkably quickly.

Yes, that is a big problem with the older autosamplers. I like in the new ones you can set it to x ul of rinse or even sample washes. I had to just use sample pumps without a sample wash using the older autosamplers if I used a small volume insert, otherwise after one injection most of the sample was gone.