An aqueous primary standard for use with the Technicon SMA 6/60.

An aqueous primary standard containing sodium, potassium, chloride, carbon dioxide, glucose, and creatinine was prepared for use with the Technicon SMA 6/60 continuous-flow analyzer. This standard, compared with a protein-base primary standard, showed no significant difference in slope, gamma-intercept, and linearity for these methods. Precision with use of the aqueous primary standard was acceptable, comparable to that for a commercial reference serum. The standard was stable for at least 30 days.