New to Chromatography - Manual Injection Technique

[Peter Apps]

Hi Michael

In HPLC you have a mechanical pump with wearing parts, in GC you have a gas cylinder. In HPLC you have to make up mobile phase every couple of days, in GC you change a cylinder once a month. In HPLC there are thousands of mobile phase recipes, in GC there are three (and they only affect the speed of the analysis). In GC you have a temperature programme, in HPLC you have mobile phase gradients. There is no HPLC equivalent of an FID (which is both a good and a bad thing). Choosing the right column is more critical in HPLC.

Peter

[MichaelStuart]

I'm happy to report that things seem to be going swimmingly. After going through three controllers, four towers, and two trays, I finally have a working auto-sampler. I think I was also saturating the column. I adjusted my split ratio from 10:1 to 20:1, and am now getting consistently about a 1%-2% deviation between determinations. I can live with that.

It seems the fast injection of the auto-sampler has circumvented the inlet discrimination that I was noticing.

Peter, thanks again for your help.

Mike

[Peter Apps]

A pleasure.

Thanks for the feedback and congratulations on getting it sorted.

Peter

[MichaelStuart]

I feel like it's kind of an off the wall question.. However, Is it possible to qualify/quantify lead in a paint chip with my 5890-s II FID/ECD?

[Peter Apps]

I feel like it's kind of an off the wall question.. However, Is it possible to qualify/quantify lead in a paint chip with my 5890-s II FID/ECD?

Possible yes, probably with some pretty exacting sample prep aiming to make a volatile derivative of the lead such as lead tetraethyl.

Practical - definitely not.

Peter

[chromatographer1]

Gc is definitely not the preferred methodology.

Atomic absorption analysis is the preferred methodology for trace levels, not necessarily a test for lead paint. Wet chemical analysis heavy metals is a nice quick and easy test.

best wishes,

Rod