CE_Sample_Problem_Key

# CE_Sample_Problem_Ke - (Ans-7.1 x 10-9 m 2/V s and-9.3 x 10-9 m 2 V s respectively From this information can you explain why Protein B elutes after

This preview shows pages 1–2. Sign up to view the full content.

You perform a CE experiment to separate a neutral molecule and two negatively charged proteins. The total length of the capillary is 0.840 m. The applied voltage is 2.50 x 10 4 V. The length of the capillary from the injector to the detector is 0.640 m. From your chromatogram you determine that the neutral molecule elutes in a time of 308 s. Protein A elutes in a time of 343 s and Protein B elutes in a time 355 s. Answer the following questions: 1. Calculate the electric field strength. (Ans: 29.8 kV/m) kV/m 29.8 m 840 . 0 V 10 x 2.50 L V E 4 t = = = 2. Calculate the electroosmotic velocity (u eo ). (Ans: 2.08 x 10 -3 m/s) m/s 10 x 2.08 s 308 m 0.640 t L u 3 - neutral d eo = = = 3. Calculate the apparent mobility ( μ app ) for Protein A and B. (Ans: 6.27 x 10 -8 m 2 /V s and 6.05 x 10 -8 m 2 / V s, respectively) s kV / m 10 x 05 . 6 kV/m 8 . 29 s 355 / m 640 . 0 E t / L E u E u : B s kV / m 10 x 26 . 6 kV/m 8 . 29 s 343 / m 640 . 0 E t / L E u E u : A s kV / m 10 x 6.98 kV/m 8 . 29 s / m 10 x 2.08 E u E u 2 5 - d net app app net 2 5 - d net app app net 2 5 - 3 - eo eo eo eo ep eo app = = = = μ μ = = = = = μ μ = = = = μ μ = μ + μ = μ 4. Calculate the electrophoretic mobility of Protein A and B.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: (Ans: -7.1 x 10-9 m 2 /V s and -9.3 x 10-9 m 2 / V s, respectively) From this information can you explain why Protein B elutes after Protein A? B Protein for s kV / m 10 x 9.3-s kV / m 10 x 6.98-s kV / m 10 x 05 . 6-so A Protein for s kV / m 10 x 7.2-s kV / m 10 x 6.98-s kV / m 10 x 26 . 6-so 2 6-ep 2 5-2 5-eo app ep ep eo app 2 6-ep 2-5 2-5 eo app ep ep eo app = μ = μ μ = μ μ + μ = μ = μ = μ μ = μ μ + μ = μ The negative sign indicates that the proteins are negatively charged and are thus trying to electrophoretically move towards the anode (positive electrode). Protein B has the larger electrophoretic mobility so it must be more negatively charged then Protein A. If Protein B has a greater negative charge it can more strongly resist the pull of the electroosmotic flow as compared to Protein A, and thus comes off later....
View Full Document

## This note was uploaded on 11/03/2009 for the course CHEM 241 taught by Professor Tiani during the Summer '08 term at UNC.

### Page1 / 2

CE_Sample_Problem_Ke - (Ans-7.1 x 10-9 m 2/V s and-9.3 x 10-9 m 2 V s respectively From this information can you explain why Protein B elutes after

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online