1. What make Cogent EE™ chiral different from other Cellulose Carbamate coated columns?



2. What is the optimal temperature range for these columns?



3. Is the use of ternary solvents safe for these columns?



4. Is hexane/Acetonitrile/Ethanol safe for these columns?



5. Will Cogent EE™ columns separate acidic chiral compounds?



6. Is it optimal to have analytes fully ionized during separation?



7. Is the retention mechanism of Cogent EE™ columns the same as other cellulose carbamate coated columns?



8. Is it correct to assume there is better control over the retention on EE™ columns by adjusting the mobile phase?



9. With regard to higher loading, is polar organic mode more beneficial over other mobile phases for the Cogent EE™ columns?



10. Are Larger particle sizes than 5µm available for the Cogent EE™ columns?



11. How long have these columns been on the market?



12. If I add an alcohol to the Acetonitrile in my mobile phase will it improve resolution?



13. Is there a class of compounds that the Cogent EE™ columns will not retain or separate?



14. What is the maximum pressure I can use with the Cogent EE™ columns?



15. Do these columns suffer from “Memory Effect” as other cellulose coated columns do?

1. What make Cogent EE™ chiral different from other Cellulose Carbamate coated columns? [top]
The proprietary coating chemistry is unique and this allows for a different retention character of the column. A relationship between analyte polar and eluent polarity exists. This may provide a more predictable, unique selectivity for the user of these columns. Therefore mobile phases that work on other similar columns may not work the same on a Cogent EE™ column. Since the solubility range of the EE™ columns are much greater than other similar columns, the sample loading may be greatley increased on the EE™ columns with optimized methods.

2. What is the optimal temperature range for these columns? [top]
These columns work at ambient temperature with a higher range of 30C. Typically, subambient temperatures favor spatially selective HPLC. Be cautious not to thermally shock any HPLC column by changing the temperatures too quickly.

3. Is the use of ternary solvents safe for these columns? [top]
Safety is all about remembering that the Cogent EE™ is a coated column and not a bonded column and must be handled appropriately. It does not matter if one solvent or four solvents are used as long as the solvents used are not hazardous to the column. A list of solvents to be avoided are supplied with every column. Generally speaking, avoid using DMF and chlorinated solvents.

4. Is hexane/Acetonitrile/Ethanol safe for these columns? [top]
Yes, in fact this is one of the best solvent combinations to use with Cogent EE™ columns. You have to remember that Acetonitrile is not soluble in hexane so you must keep the concentration of it low. If 10% or less Acetonitrile is used and 3 times the amount of ethanol is used (ration of 3:1 EtOH/ACN) overall combination should not exceed 65/45 hexane/(EtOH/ACN).

5. Will Cogent EE™ columns separate acidic chiral compounds? [top]
Yes, possibly, but the biggest issue for all chiral compounds is lack of absolute predictability. It is hard to answer this question without knowing the specific acid compound. The best way to know is to try is under several suggested EE™ methods.

6. Is it optimal to have analytes fully ionized during separation? [top]
Yes, standard practice in chiral HPLC is to use acid or base forms of analytes for separation.

7. Is the retention mechanism of Cogent EE™ columns the same as other cellulose carbamate coated columns? [top]
Similar but not exactly the same. What makes these columns unique is proprietary but what really matters is the results.

8. Is it correct to assume there is better control over the retention on EE™ columns by adjusting the mobile phase? [top]
With regard to pH and buffers, ABSOLUTELY. This is one of the most powerful and unique features of EE™ columns.

9. With regard to higher loading, is Polar Organic mode more beneficial over other modes including Normal Phase using the Cogent EE™ columns? [top]
Yes! To optimize this, you should not use 100% Methanol or 100% Acetonitrile as one of your mobile phase components. Use instead 100% IPA or 50/50 IPA/Methanol or IPA/ACN then use then feed in your buffer as an eluent solvent. This can be very powerful for non resolving enantiomeric pairs.

Loading capacity on columns is always related to the solubilities of the samples, the mobile phase and the stationary phase. With the Cogent EE™ columns, the solubility/affinity of the eluent is more often related to the eluent that is used in ordinary HPLC which is very beneficial in preparative chiral LC.

10. Are Larger particle sizes than 5µm available for the Cogent EE™ columns? [top]
Yes, Cogent EE™ columns and bulk stationary phase are available in 5, 10 and 20µm, wide pore, spherical particles using out proprietary coating technology.

11. How long have these columns been on the market? [top]
This technology has been available in Europe sold under a different brand name since 2005. Now Cogent EE™ columns are available through MicroSolv on a global basis.

12. If I add an alcohol to the Acetonitrile in my mobile phase will it improve resolution? [top]
Yes, in most cases but not always.

13. Is there a class of compounds that the Cogent EE™ columns will not retain or separate? [top]
There are many compounds that Cogent EE™ may not separate. However, as with every other cellulose carbamate column, there is no way to predict if these columns will work or not for any specific compound set.

14. What is the maximum pressure I can use with the Cogent EE™ columns? [top]
These columns have been used at 2,000 psi without any damage to them.

15. Do these columns suffer from “Memory Effect” as other cellulose coated columns do? [top]
All cellulose columns are subject to “memory effect” where many additives are retained in the stationary phase once it is exposed to them. The Cogent EE™ columns are much less prone to this effect and therefore are easy to equilibrate very quickly. This makes the runs faster and more precise.