2-Hydroxy-1,2,3-propanetricarboxylic acid zinc salt, dihydrate [5990-32-9].
Zinc Citrate contains NLT 31.3% of zinc (Zn), calculated on the dried basis.
• A. Identification TestsGeneral, Zinc 191: A solution (1 in 10) meets the requirements.
• B. Identification TestsGeneral, Citrate 191: A solution (1 in 10) meets the requirements.
Sample: 350 mg of Zinc Citrate, previously dried at 105 for 2 h
Blank: 60 mL of water
(See Titrimetry 541.)
Mode: Direct titration
Titrant: 0.05 M edetate disodium VS
Endpoint detection: Visual
Analysis: Dissolve the Sample in 60 mL of water. Add 10 mL of ammoniaammonium chloride buffer TS and 0.1 mL of eriochrome black TS. Titrate with the Titrant to a blue endpoint. Perform a blank determination.
Calculate the percentage of zinc (Zn) in the portion of Zinc Citrate taken:
Result = [(V B) × M × F × 100]/W
Acceptance criteria: NLT 31.3% on the dried basis
• Chloride and Sulfate, Chloride 221: A 1.0-g portion shows no more chloride than corresponds to 0.7 mL of 0.020 N hydrochloric acid (NMT 0.05%).
• Chloride and Sulfate, Sulfate 221: A 1.8-g portion shows no more sulfate than corresponds to 0.5 mL of 0.020 N sulfuric acid (NMT 0.05%).
• Limit of Arsenic, Cadmium, and Lead
Arsenic standard solution: 1.0 µg/mL in 1% nitric acid, prepared from an arsenic standard solution (10 mg/L)
Cadmium standard solution: 1.0 µg/mL in 1% nitric acid, prepared from a cadmium standard solution (10 mg/L)
Lead standard solution: 1.0 µg/mL in 1% nitric acid, prepared from a lead standard solution (10 mg/L)
Multi-element standard solution: 10 µg/L of lead, 5 µg/L of cadmium, and 3 µg/L of arsenic in 1% nitric acid, prepared from the Lead standard solution, Cadmium standard solution, and Arsenic standard solution, respectively
Sample solution: 2 mg/mL of Zinc Citrate in 1% nitric acid
(See Plasma Spectrochemistry 730.)
Radio frequency: 1350 Watts
Nebulizer flow rate: 0.9 L/min
[NoteThe radio frequency and nebulizer flow rate settings may be developed and optimized based on the manufacturer's recommendation. ]
Detection atomic masses: As, Cd, and Pb
Blank: 1% nitric acid solution
Samples: Multi-element standard solution, Sample solution, and Blank
Determine the responses of the Multi-element standard solution, Sample solution, and Blank at the masses indicated above.
Calculate the content of each element, in µg/g, in the portion of Zinc Citrate taken:
Result = (rU/rS) × (CS/CU)
Arsenic: NMT 3 µg/g
Cadmium: NMT 5 µg/g
Lead: NMT 10 µg/g
• Loss on Drying 731: Dry a sample at 105 for 2 h: it loses NMT 1.0% of its weight.
• Microbial Enumeration Tests 2021: The total aerobic microbial count does not exceed 103 cfu/g. The total combined yeasts and molds count does not exceed 102 cfu/g.
• Microbiological Procedures for Absence of Specified Microorganisms 2022: It meets the requirements of the test for absence of Escherichia coli.
• Packaging and Storage: Preserve in well-closed containers.
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 1662Pharmacopeial Forum: Volume No. 34(2) Page 315