The use of borate buffer in paper electrophoresis of serum.

Conditions of Electrophoresis.-The apparatus used was similar to that described by Franglen (1953). It consisted of a flat shallow " perspex " box in which a sheet of Whatman No. 1 paper was stretched horizontally with the ends dipping into the electrode solutions. The paper was first wetted with electrolyte, blotted, and placed in position in the apparatus. Serum (10lI.) was then applied from a micropipette along a length of about 2.7 cm. of the starting line, which was placed towards the cathode end. The voltage applied was 14-15 V/cm. for two and a half to three hours and average current varied with the nature of the buffer used but in most experiments was 0.4-0.5 mA/cm. width. Electrophoresis was carried out at room temperature; the paper strips were dyed with bromphenol blue according to Kunkel and Tiselius (1951). Buffer Solutions.-All buffers had pH 8.6 (glass electrode). The three buffers used in this investigation were (1) 0.05 M barbitone as described by Durrum (1950); (2) 0.2 M borate buffer, prepared by mixing 0.2 M boric acid (3.5 vol.) with 0.2 M sodium hydroxide (1 vol.); (3) borate-barbitone buffer prepared by mixing equal volumes of (1) with 0.1 M borate buffer. The latter was half strength buffer (2).