Chromatography Forum

Hi Everyone

I need some help in determining relative response factors (RRF). The impurities that I am looking at are not readily available, therefore I need to calculate RRF for feature determination.
Slope of impurity = 25557908 (from linearity curve)
Concentration of impurity = 0.0015 mg/ml
Slope of API = 30545354 (from linearity curve)
Concentration pf API = 0.0010 mg/ml

Question ?

- How do I calculate RRT
- How do I use it to determine the % impurity when the impurity is not weighed off.

Thanks in advance
Mike Carolus

concerning the RRF:
not that i know the correct response to that i think that. i can look it up somewhere in my litterature but I think we are missing 2 parameters:

are the chromophores the same for both compounds (i think that you can't just extrapolate it if the answer is no)? you will need to know the exact structure of your compounds for that.

what are the Mw for both compounds?

for RRT:
do you seek simple RRT as t2/t1
when response is >1 then t2>t1.



or do you mean selectivity as (t0-t2)/(t0-t1)
to being the unretained time peak.


and the last one, the % of impurity i can't remeber right now. the answer is at the office.

Please ignore this message as I have made a few mistakes. Refer to new message.

Thanks