Chromatography Forum

i am a newcomer in the field of chromatography, in our lab analysis of drugs from biological fluids is done, for this usually mobile phase contaning Triethylamine is used? i jsut want to know why it is preffered? i heard that it also damages the column? then why use it?

i am a newcomer in the field of chromatography, in our lab analysis of drugs from biological fluids is done, for this usually mobile phase contaning Triethylamine is used? i jsut want to know why it is preffered? i heard that it also damages the column? then why use it?

TEA is used as ion pairing reagent ...in case your analyte is in ionisable form to enhance its retention ion pairing reagent is used and to avoid peak tailing.

TEA being basic...higher concentration of this will raise pH and working outside the pH range of column (which is ususally 2-7 for ODS columns) results in dissolution of silica.

Hope its clear now.

Regards,

Amaryl.

How long you will be new comer to chromatography...we all are learners in some way or other

The majority of drugs have basic properties. In this case it is more likely that TEA is being used as a masking agent to block the detrimental interactions of basic drugs with ionized silanol groups on ODS columns. Usually the pH is adjusted with something like phosphoric acid so that it is within the range 2-7. In this case basic drugs and TEA are present as cations, and there is no possibility of ion pairing occurring.

With some modern columns the use of TEA is not necessary. It is possible that the TEA may alter the properties of the column irreversibly, so it may be prudent to reserve it for these applications, rather than to switch to separations not involving TEA. However, I have observed serious effects of this nature only with longer chain amines which may also be used for the same purpose.

In some cases TEA is used to achieve very high pH (e.g. 10-12) which can be used with a few highly pH stable phases so that basic drugs can be analyzed as netural species. This application is relatviely rare.