Helium-Glow Photometer for Picomole Analysis of Alkali Metals.

The low-power electricglow discharge in helium can excite efftctively the characteristic emission lines of sodium and potassium. The helium-glow photometer used to generate the glow and measure the light is a relatively simple apparatus; it can be used to analyze samples containing 10(-14) mole or more of sodium and potassium. Overall precision of the apparatus and method is 5 percent or better.