Chemiluminescence Reaction of an Iron(III)-Phthalocyanine Complex and Its Application to FIA of L-Tyrosine

Chemiluminescence (CL) of a metal–phthalocyanine complex was studied, and an analytical application of CL detection-flow injection analysis (FIA) of L-tyrosine was developed. The CL reaction of iron (III)–phthalocyanine tetrasulfonic acid (Fe–PTS) was examined using eight metals (Cu, Fe, Ni, Co, Mg, Pd, Pt and Zn)–phthalocyanine complexes. The CL signal immediately appeared, when the Fe-PTS aqueous solution was injected into a hydrogen peroxide solution. Moreover, the influence of foreign substances on the CL system of Fe–PTS was examined. The decrease in the CL intensity of the iron–phthalocyanine complex was caused by adding a reducing agent such as L-tyrosine. The CL detection-FIA of trace amounts of L-tyrosine was then developed using this quenching phenomenon. The calibration curve was obtained in the concentration range 2.5 × 10 M to 7.5 × 10 M, and the sampling rate was 150 samples h. Further, the relative standard deviation (RSD) was 1.20 % (n = 25) for 1.0 × 10 M, and the detection limit (3σ) were 8.54 × 10 M. The interference of metal ions was able to inhibit using EDTA. Therefore, the interference of L-cysteine was able to inhibit using Zn. As an application to a practical sample, L-tyrosine in a supplement was determined. The experimental value is almost the same as the tabulated one (1.0 × 10 M) measured by amino acid autoanalyzer at the Japan Food Research Laboratories.