Chromatography Forum

Hi,

I am attempting to do quantitative analysis of triethanolamine (extracted from industrial fluids by ion exchange SPE) by split injection GC/FID on an RTX-35 amine column.

Reproducibility of standards is very bad. I have eliminated injection as a source of error, and other ethanolamines don't seem to behave so badly. My calibration curve is poor, and area counts jump for a single standard by a great deal.

This just doesn't make any sense to me....does anybody have ideas or suggestions????

Thanks!!

Amines can be tough under any conditions, and triethanolamine is very polar. Dissolve the sample in DMF, filter if cloudy. Mix a portion with equal amount of BSTFA derivatizing agent. Use split injection, DB-1 or DB-5 type capillary column, program from somewhere about 80C up to like 240C at 10C/minute; do this way or determine what temperature you need for isothermal GC. I've done this assay this way for years, the three hydroxy groups will derivatize.

Not sure what concentrations your looking at but I've succesful
used CP Sil 8CB capillary column with the following conditions
90°C for 10 mins then 8°C/minute to 240°C for solutions of Mono, Di and Tri ethanolamine.

A 25 times dilution in MeOH and an area % method gave good repeatability.