Quenching-chemiluminescence determination of trace amounts of l-tyrosine contained in dietary supplement by chemiluminescence reaction of an iron-phthalocyanine complex

The chemiluminescence (cl) signal immediately appeared when a hydrogen peroxide solution was injected into an iron-phthalocyanine tetrasulfonic acid (fe-pts) aqueous solution. moreover,the cl intensity of fe-pts decreased by adding l-tyrosine. based on these results,the determination of trace amounts of l-tyrosine was developed using the quenching-chemiluminescence. the calibration curve of l-tyrosine was obtained in the concentration range of 2.0 10 -7 m to 2.0 10 -5 m. moreover,the relative standard deviation (rsd) was 1.63 % (n=5) for 2.0 10 -6 m l-tyrosine,and its detection limits (3δ) were 1.81 10 -7 m. the spike and recovery experiments for l-tyrosine were performed using a soft drink. furthermore,the determination of l-tyrosine was applied to supplements containing various kinds of amino acids. each satisfactory relative recovery was obtained at 98 to 102%. copyright 2012 takao ohtomo et al.