Biopartitioning Micellar Chromatography (BMC) which is a mode of Micellar Liquid Chromatography , quantitative retention Activity Relationship QRAR models have been testified to be useful for describing and predicting the biological activities of different pharmacological kinds of drugs.
Chromatographic retention data are extremely needed , how can I calculate retention factor log K using thiourea in Micellar liquid Chromatography?
Please your guidance is needed!
thanks
Dear Sir. Concerning your issue about the calculation of retention factor using thiourea in HPLC system. To define Retention Factor (k), Selectivity (α), and Efficiency (N) in chromatography and show how each can be determined and optimized. Retention factors, k, were calculated using k = (tR – t0)/(t0 – ti) where tR is the retention time (measured from the apex of each peak), t0 is column dead time, and ti is the instrument dead time (the time it takes for an injected solute to reach the detector when the column is bypassed). The data acquisition rate of the MS detector was not a major factor contributing to error as the acquisition rate was roughly 10 Hz (corresponding to a mass spectrum every 0.002 min). Thiourea was spiked into the test mixture and used as the dead time marker. Although it is slightly retained at lower acetonitrile concentrations, thereby biasing the retention factors, it does not bias the back-calculated gradient or the projected retention times because the t0 used in the t0 vs. Φ profiles that are used to project retention times is also a thiourea dead time, canceling any bias it might have otherwise caused. To measure the instrument dead time, the column was first removed and replaced with a zero dead volume connector. Then the test mixture was subjected to an isocratic run at 50% B and 0.4 mL/min flow rate and the tetrabutylammonium ion (242 m/z) was monitored, which is convenient because it gives an especially strong MS signal. The elution time of tetrabutylammonium was then used as the instrument dead time. I think the following below links may help you in your analysis:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4556278/pdf/nihms-716543.pdf http://www.chromacademy.com/lms/sco2/Theory_Of_HPLC_Chromatographic_Parameters.pdf
Thanks
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thanks Sir,
what about using this formula of retention factor seen on the reference you sent to me, k = (tR – t0)/t0
as the formula has been used in paper here below
thanks
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