Quenching-Chemiluminescence Determination of Trace Amounts of l-Tyrosine Contained in Dietary Supplement by Chemiluminescence Reaction of an Iron-Phthalocyanine Complex

Table 2

Influence of foreign substances.

Foreign substance	[Foreign substance]/[L-tyrosine]
Glutamine, methionine, serine, threonine, alanine, glycin, isoleucine, glucose, fructose, xylose, saccharose, raffinose, levulose, lactulose, galactose, nicotinic acid, nicotinamide, sodium pantothenate	1000
Asparagine, lysine, phenylalanine, histidine, leucine, proline	500
Ca^2+, Zn^2+, Mn^2+, valine, aspartic acid cysteine*	100
Se^4+, V^5+, Al^3+, arginine, pyridoxine hydrochloride, thiamine hydrochloride	50
EDTA, Ni^2+,* Co^2+,* Cu^2+,* Fe^3+, glutamic acid, riboflavin, folic acid	10
Cystine, tryptophan, ascorbic acid	5

Tolerance limit is within ±5% error for CL intensity when [L-tyrosine]_T  is 2.0 × 10⁻⁶ M.
*[EDTA]_T: 2.0 × 10⁻⁵ M was added as a masking reagent.
*[Zn²⁺]_T: 2.0 × 10⁻⁴ M was added as a masking reagent.