1. What is CElixir-SDS™?
2. What is the pH range of CElixir-SDS™?
3. What is the UV wavelength that I should use for CElixir-SDS™?
4. What would you suggest for Internal Standards for the Kits?
5. What is the buffer concentration of CElixir-SDS™?
6. Can CElixir-SDS™ be used for Proteins?
7. Is there anything in CElixirOA™ that can pit or damage a bare fused silica capillary in any way?
8. Can temperature have an effect on CElixir-SDS™?
9. How many test runs should I expect from one CElixir-SDS™ kit?
10. How many coatings should I expect from 1.4ml of CElixir-SDS Initiator™ solution? How long will a vial of this solution last?
11. Can I get a different formulation of CElixir-SDS™ for my specific application?
12. What is the advantage of a dynamic coating using MEKC?
13. What can I dilute the run buffer with? Can I adjust the pH?
14. How does CElixir-SDS™ separate neutral molecules using CE?
15. Can I add SDS to change the molarity?
16. Can I add chiral selectors such as cyclodextrin to the run buffer for chiral analysis?
17. What does MEKC stand for?
18. I have been using an SDS buffer for MEKC in the past and have found that migration times increase with day to day runs. Eventually, I have to replace the capillary. What kind of Day to Day and Run to Run reproducibility of migration times can I expect with CElixir-SDS™?
19. I want to use CElixir-SDS™ but I need to work at pH 6.5. How can I do this?

1. What is CElixir-SDS™? [top]
CElixir-SDS™ is a kit of pre-made buffers that are used to separate non charged and charged molecules using CZE. The kit uses the CElixir™ dynamic coating technology in order to stabilize the EOF and minimize wall adsorption of analytes. SDS (sodium dodecyl sulfate) is pre-mixed to create micelles for hydrophobic separation of neutral molecules using MEKC.

Each kit is supplied with 3ml of Initiator Solution, 90ml of Accelerator Solution and 90ml of Diluent Solution, these kits are ready to be used or modified for your specific needs.

2. What is the pH range of CElixir-SDS™? [top]
CElixir-SDS™ is supplied, ready to be used, at pH 9.2. The Accelerator Solution (the run buffer) is a Borate buffer based solution containing the polyanion component of the dynamic coating and by adding Boric Acid, you can adjust the pH to 8.2 or by adding Phosphoric Acid, you can adjust the pH to 6.2.

3. What is the UV wavelength that I should use for CElixir-SDS™? [top]
If a Diode Array detector is available, it is suggested to use it. However, any individual wavelength should be selected depending on the UV maxima of your samples. There are no restriction on the UV range of CElixir-SDS™.

4. What would you suggest for Internal Standards for the kits? [top]
Any pure compound that migrates differently than the EOF could be used, however, for example, compounds such as Caffeine, Sorbate, Benzoate, Saccharine or Quinine be used. We suggest these because they migrate at different rates with CElixir-SDS™ and are neutral.

5. What is the buffer concentration of CElixir-SDS™? [top]
CElixir-SDS™ (catalog number 06200-75) contains an Accelerator solution with a Borate Buffer (12.5mM) and SDS (50mM); other pre-made solutions are available, contact our customer service department for details.

6. Can CElixir-SDS™ be used for Proteins? [top]
Yes, several articles describe using MEKC with SDS for protein separations. Our R&D lab will document this further.

7. Is there anything in CElixir-SDS™ that can pit or damage a bare fused silica capillary in any way? [top]
No, CElixir-SDS™ is designed to work with bare fused silica capillaries and is not recommended for permanently coated capillaries.

8. Can temperature have an effect on CElixir-SDS™? [top]
Yes, as with any CE method, temperature is something that should be controlled during each test run.

9. How many test runs should I expect from one CElixir-SDS™ kit? [top]
CElixir-SDS™ is designed to provide between 150 and 250 test runs. The actual outcome is determined by the waste in your particular system, how careful you can be, the length of your capillary, run times and of course sample matrix.

10. How many coatings should I expect from 1.4ml of CElixir-SDS Initiator™ solution? How long will a vial of this solution last? [top]
If you follow our Operating and Instruction Manual for CElixir-SDS™, the coating solution (Initiator (A)) is used only once (1) per day or when a new capillary is used. Once you coat your capillary and remove the autosampler vial from the instrument and return the solution to a fresh, clean vial with a solid, inert cap, the remaining solution should be good for up to 30 more coatings. If the solution is stored properly (do not refrigerate) it should be good for many weeks or months.

11. Can I get a different formulation of CElixir-SDS™ for my specific application? [top]
Yes, our R&D lab is very happy to work with you and develop a “custom” kit for your application needs. For more information, contact our Technical Service Department.

12. What is the advantage of a dynamic coating using MEKC? [top]
Reproducibility! By stabilizing the EOF and by minimizing wall adsorption of analytes, precision is increased to well beyond demands of the most critical labs. By using a commercially available kit such as CElixir-SDS™, method transferability to other labs such as a QC environment is more likely to succeed. Speed and ease of use are also benefits.

13. What can I dilute the run buffer with? Can I adjust the pH? [top]
One of the advantages of CElixir-SDS™ is that you can adjust the kit for your specific separation needs. You can use any of the solutions below to adjust the method:

Methanol (up to 20%) Acetonitrile (up to 10%) Propanol (up to 10%) Isopropanol (up to 15%)

15. Can I add SDS to change the molarity? [top]
Yes, you can add reagent grade SDS and change the SDS concentrations. This may change the overall EOF and the run times and other expected results.

16. Can I add chiral selectors such as cyclodextrin to the run buffer for chiral analysis? [top]
Yes, you can add reagent grade or better CD (cyclodextrins) listed below for chiral and enhanced separations.

Beta-Cyclodextrin Gamma-Cyclodextrin dimethyl Beta-Cyclodextrin hydroxypropyl Beta-cyclodextrin hydroxyethyl Beta-Cyclodextrin and others...

18. I have been using an SDS buffer for MEKC in the past and have found that migration times increase with day to day runs. Eventually, I have to replace the capillary. What kind of Day to Day and Run to Run reproducibility of migration times can I expect with CElixir-SDS™? [top]
Properly using the CElixir-SDS™ kit for MEKC, you will find much improved run to run and day to day reproducibility over many standard SDS methods. You can usually expect below 1% RSD of migration times for the first N runs within the first day. The next day, you can expect approcimately 0.3%. For intraday RSD you should see below 3% for the first two - three days; then the RSD will improve and stabilize to better than 1%.

19. I want to use CElixir-SDS™ but I need to work at pH 6.5. How can I do this? [top]
You can lower the pH of the Accelerator buffer with phosphate however it is difficult to measure pH due to the SDS. Therefore we suggest that you contact our technical department or use this link to inquire about a Custom made CElixir-SDS™ at this pH.