A highly sensitive colorimetric determination of serum copper using alpha, beta, gamma, delta-tetrakis(4-N-trimethylaminophenyl)porphine.

A colorimetric method is presented for the accurate determination of serum copper in 0.1 ml sized samples, using alpha, beta, gamma, delta-tetrakis(4-N-trimethylaminophenyl)porphine. This new reagent has high sensitivity (epsilon 433nm = 5.1 X 10(5) l.mol--1.cm--1), it is water-soluble and has long-term stability at the pH range of 4--9 at room temperature. Metal ions and organic compounds even at levels greater than normally found in serum do not affect the determination. The coefficient of variation of this method is less than 3%. In addition, a good correlation was obtained between this method and the Landers and Zak method (r = 0.98).