Chromatography Forum

Having problems getting the latest USP method for TEC assay to work. Under the current conditions (split ratio 30:1) I am overloading the column and when I increase the split ratio to 100:1 or 150:1 I can't get consistent peak areas.

TEC boiling point is 127C but injector temp only at 85C. Does this seem weird to anyone but me?

Also, can anyone recommend what type of liner to use in the injector? One of my co-workers say I should use the direct inject liner w/out glass wool.

Anyone have any ideas?

Thanks.

That low inlet temperature would seem strange to me as well (does USP call for a temperature-programmable inlet, like in some of their other procedures?). That could be the irreproducible-split reason. My experience has resulted in my disappointment with several USP procedures.