To separate Hb S from Hb D, electrophoresis should be performed under which conditions?

To separate Hb S from Hb D, electrophoresis should be performed under which conditions?

• A. Electrophoresis on a different medium and acidic pH
• B. Electrophoresis on the same medium and neutral pH
• C. Kleihauer-Betke acid elution
• D. Isoelectric focusing

Answer: (A)

Migration in electrophoresis depends on net charge at the operating pH and how the molecule interacts with the supporting medium. Hb S and Hb D have very similar mobility under the common alkaline conditions used on some media, so they can co-migrate and appear as the same band. Running electrophoresis on a different medium with an acidic pH changes the charge state of the hemoglobins and alters how they move through the gel, allowing Hb S and Hb D to separate into distinct bands. This difference in mobility under acidic conditions on another medium is what reveals which variant is present. The other options don’t address the need to shift both the medium and pH to differentiate the two variants.

Migration in electrophoresis depends on net charge at the operating pH and how the molecule interacts with the supporting medium. Hb S and Hb D have very similar mobility under the common alkaline conditions used on some media, so they can co-migrate and appear as the same band. Running electrophoresis on a different medium with an acidic pH changes the charge state of the hemoglobins and alters how they move through the gel, allowing Hb S and Hb D to separate into distinct bands. This difference in mobility under acidic conditions on another medium is what reveals which variant is present. The other options don’t address the need to shift both the medium and pH to differentiate the two variants.