The quality grades of zinc gluconate raw materials are typically classified based on usage, purity, impurity control, and production standards, with different grades suitable for pharmaceuticals, food, industry, and other fields. The main quality grades and their characteristics are as follows:
I. Pharmaceutical Grade
Core Standards
Purity Requirements: Pharmaceutical-grade zinc gluconate typically has a purity of ≥99.0% (calculated as anhydrous substance), conforming to official pharmacopoeia standards such as the Chinese Pharmacopoeia (ChP), United States Pharmacopeia (USP), and European Pharmacopoeia (EP), with extremely strict impurity control.
Safety Indicators:
Heavy metals: Lead (Pb) ≤10ppm, Arsenic (As) ≤2ppm, and harmful elements like Cadmium (Cd) must meet the requirements for pharmaceutical excipients.
Microorganisms: Pass microbial limit tests (e.g., total bacteria, molds, and yeasts ≤100cfu/g); raw materials for sterile preparations must meet sterile standards.
Organic solvent residues: If solvents like ethanol are used in production, residues must be controlled (e.g., ethanol residue ≤0.5%).
Application Scenarios
Used for preparing oral formulations (tablets, capsules, oral liquids), external preparations (ointments), or injections (rare, requiring additional safety verification), serving directly as active pharmaceutical ingredients (API) or pharmaceutical excipients, and requiring certification under Good Manufacturing Practice (GMP) for drugs.
II. Food Grade (Nutritional Fortifier Grade)
Core Standards
Purity Requirements: Purity ≥98.0%, conforming to National Food Safety Standards for Food Nutritional Fortifiers Zinc Gluconate (GB 1903.19-2016) or standards of the Codex Alimentarius Commission (CAC).
Safety Indicators:
Heavy metals: Lead ≤2ppm, Arsenic ≤1ppm, with stricter control of harmful elements.
Microorganisms: Comply with hygiene standards for food additives (e.g., total bacterial count ≤1000cfu/g, coliforms ≤30MPN/100g), and free of pathogenic bacteria (Salmonella, Staphylococcus aureus).
Physicochemical properties: Loss on drying (moisture) ≤11.0% (with crystal water), pH value (5% aqueous solution) 5.5-7.0, ensuring taste and stability.
Application Scenarios
As a food nutritional fortifier added to dairy products, beverages, infant foods, and health products, requiring food production licensing (SC certification), with emphasis on safety and taste adaptability (odorless, no impact on food color).
III. Feed Grade
Core Standards
Purity Requirements: Purity ≥95.0%, focusing on zinc content (calculated as Zn ≥14.3%), with lower impurity control requirements than pharmaceutical and food grades.
Safety Indicators:
Heavy metals: Lead ≤30ppm, Arsenic ≤10ppm, meeting safety needs for livestock, poultry, and aquaculture.
Physicochemical properties: Good water solubility to prevent feed caking or affect animal absorption due to impurities.
Application Scenarios
Used for zinc nutrition supplementation in animal feeds to promote growth and improve immunity (e.g., pig, chicken, fish feeds), complying with the Specifications for Safe Use of Feed Additives, with strict cost control and focus on cost-effectiveness and zinc supplementation efficiency.
IV. Industrial Grade
Core Standards
Purity Requirements: Purity ≥90.0%, allowing a certain amount of impurities (inorganic salts, organic by-products), mainly controlling zinc content and basic physicochemical properties (water solubility, pH value).
Characteristics:
Cost-oriented: Simplified production process, lower price, suitable for industrial scenarios with low purity requirements.
Impurity tolerance: No strict limits on heavy metals and microorganisms, but must meet basic requirements for specific industrial uses (e.g., no mechanical impurities affecting use).
Application Scenarios
Used in electroplating (as a zinc ion source to improve coating uniformity), chemical synthesis (as a catalyst or intermediate), wood preservative treatment, etc., without involving food or pharmaceutical fields, with functional and economic considerations as the main focus.
V. Reagent Grade (Analytical Pure / Chemical Pure)
Core Standards
Purity Requirements: Analytical pure (AR) ≥99.5%, Chemical pure (CP) ≥98.0%, conforming to national standards for chemical reagents (e.g., GB/T 2307-2015), focusing on controlling impurities that interfere with analytical experiments.
Indicator Characteristics:
Impurity analysis: Strict control of chloride, sulfate, iron, copper, and other elements (e.g., chloride ≤0.001%), suitable for laboratory analysis, scientific research experiments, or standard substance preparation.
Physicochemical properties: Loss on drying, pH value, and other indicators meet the precision requirements of analytical experiments.
Application Scenarios
As chemical analysis reagents (e.g., zinc standard solutions for titration analysis), raw materials for scientific research experiments (e.g., drug synthesis intermediate research), or reference standards (for method validation of content determination), requiring detailed impurity analysis reports.
Core Influencing Factors of Grade Differences
Purity and Impurity Control: Pharmaceutical grade > Food grade > Feed grade > Industrial grade. Higher purity means stricter control of impurities (especially heavy metals and microorganisms).
Application Regulations: Pharmaceutical grade must comply with pharmacopoeia and GMP requirements; Food grade must meet food safety standards; Feed and industrial grades follow industry or enterprise standards.
Cost and Cost-Effectiveness: Higher purity leads to higher production costs (purification, testing). Prices of pharmaceutical and food grades are significantly higher than industrial and feed grades.
In practical applications, users should select raw materials of corresponding grades based on specific scenarios (drug production, food addition, industrial use) and verify their compliance with relevant technical standards.
