21. Immunoelectrophoresis techniques are designed to separate the mixture components from each other by using electrophoresis
A. prior to reaction with antibody
B. prior to reaction with antigen
C. after reaction with antibody
D. after reaction with antigen
22. Which of the following is a positively charged matrix for ion exchange chromatography?
A. CM cellulose
B. DEAE cellulose
C. Phosphocellulose
D. None of these
23. Which of the following is an immunoelectrophoresis technique?
A. Two-dimensional immunoelectrophoresis
B. Counterimmunoelectrophoresis
C. Coimmunoelectrophoresis
D. Both (a) and (b)