For quantitative determination of zinc ion Zn²⁺ and evaluation of drug effects on zinc metabolism. Key Features: Sensitive and accurate. Uses 50 µL samples. Linear detection range 0.12 µM (0.78 µg/dL) to 10 µM (65 µg/dL) zinc in 96-well assay format. Simple and high-throughput. The procedure involves addition of a single working reagent and incubation for 30 min. Can be readily automated as a high-throughput assay for thousands of samples per day. Improved reagent stability and versatility. The optimized formulation has greatly enhanced reagent and signal stability. Cuvette or 96-well plate assay formats possible. Low interference in biological samples. No pretreatments are needed. Method: OD425nm. Samples: Serum, plasma, urine, saliva, food, beverage and environment. Species: All. Procedure: Assay takes 30 min. Kit size: 250 tests. Detection limit: 0.78 µg/dL (0.12 µM).