526 VOLUME II. SAMPLE PREPARATION AND APPLICATIONS

The use of liquid scintillation counting in clinical lab-oratories and for biomedical research has increased greatly over the more than 25 years that commercial LS counters have been available. Vibrating reed electrometers and gas-filled ionization detectors for the measurement of tritiurt, and carbon 14 respectively have been supplanted by LSC. Other commonly emplosed isotopes for which LSC is now the preferred method are: 2p, 35s, 5Ca, 55Fe, and the ct-emitting actinides (Mc-Dowell and Weiss, 1976). Other isotopes counted by LSC have recently been listed by Gibson (1976), Bransome and O'Conne