The storage and packaging of zinc gluconate raw materials should be standardized in terms of packaging material selection, environmental control, and safety protection in combination with its physicochemical properties and stability requirements to ensure the quality stability of the raw materials during storage. The specific requirements are as follows:
I. Adaptability Requirements for Packaging Materials
Moisture-Proof and Barrier Materials
Zinc gluconate is prone to moisture absorption (easy to agglomerate in an environment with humidity ≥65%), so the packaging materials should have high barrier properties:
Inner packaging: Food-grade or pharmaceutical-grade polyethylene (PE) bags, aluminum foil bags, or double-layer composite film bags (such as PE + aluminum foil) are preferred, and heat sealing technology is used to ensure sealing and prevent external moisture from penetrating. For example, bulk pharmaceutical chemicals are often packaged in cardboard drums lined with polyethylene film, and the film thickness should be ≥0.1mm to block moisture in the air (moisture permeability ≤5g/day).
Outer packaging: Corrugated cartons or iron drums are used to enhance mechanical protection and avoid damage to the inner packaging. For industrial-grade bulk raw materials, ton bags can be used, with the outer layer being a polypropylene woven bag and the inner layer being a polyethylene film to ensure overall waterproof performance.
Anti-Chemical Corrosion and Inert Materials
The aqueous solution of zinc gluconate is weakly acidic (pH 5.5-7.0), and the packaging materials should be acid-resistant and not react chemically with the raw materials:
Metal materials (such as iron and copper) should be avoided to directly contact the raw materials to prevent metal ion migration from affecting the purity (such as iron ion pollution will cause the raw materials to discolor). If metal containers must be used, the inner wall should be coated with an inert coating (such as epoxy resin).
The sealing glue at the packaging seal should be made of food-grade silica gel or polytetrafluoroethylene to prevent the plasticizer in the glue from migrating to the raw materials and affecting safety (such as pharmaceutical-grade raw materials should comply with the limits of packaging material migrants in the Chinese Pharmacopoeia).
II. Control Standards for Storage Environment
Precise Management of Temperature and Humidity
Temperature: The storage temperature should be controlled at 15-25°C, and high temperature (>30°C) should be avoided to accelerate the decomposition of gluconate or the oxidation of zinc ions. If the ambient temperature is too high in summer, the warehouse should be equipped with air conditioners or cool cabinets to ensure that the temperature fluctuation does not exceed ±5°C; in winter, it is necessary to prevent the temperature from being too low (<5°C) to cause the raw materials to crystallize and precipitate, affecting fluidity.
Humidity: The relative humidity should be ≤60%. Silica gel desiccant can be placed in the packaging (dosage: 5-10g desiccant per 1kg raw material), or a dehumidifier can be installed in the warehouse to monitor the humidity regularly (recorded twice a day). When the humidity exceeds the standard, the dehumidification equipment should be started in time to prevent the raw materials from absorbing moisture and agglomerating (the solubility decreases by about 10% after agglomeration).
Light Protection and Anti-Oxidation Measures
Although zinc gluconate has good light stability, long-term exposure to strong light may cause photoxidation of gluconate. Therefore:
The storage area should be kept cool and dark, and the warehouse windows should be equipped with blackout curtains to avoid direct sunlight; the raw material packaging can be covered with a black light-shielding bag, or brown glass bottles can be used for packaging (suitable for small laboratory packages).
If the raw materials need to be stored for a long time (more than 12 months), nitrogen (purity ≥99.9%) can be filled into the packaging to expel air to inhibit oxidation, and a gas one-way valve can be set at the seal to prevent external air from penetrating.
III. Packaging Identification and Safety Specifications
Clear Identification and Traceability
The following information should be marked on the outer packaging to ensure warehouse management and use safety:
Raw material name (zinc gluconate), molecular formula (C12H22O14Zn), CAS number (4468-02-4), batch number, and production date for traceability;
Storage conditions ("in a cool and dry place", "sealed in the dark"), shelf life (usually 2-3 years, and it should be used up within 3 months after opening), and warning signs such as "moisture-proof" and "anti-heavy pressure".
Zoned Storage and Safety Protection
The raw materials should be stored separately from toxic and harmful substances (such as pesticides and chemical reagents), strong oxidants (such as hydrogen peroxide), and acid-base substances to prevent cross-contamination. For example, set up an independent bulk pharmaceutical chemical storage area in the warehouse, which is at least 1 meter away from other chemical raw materials.
When handling, it should be loaded and unloaded lightly to avoid packaging damage (such as when using a forklift to handle, the pallet should be flat to prevent the barrel from tilting and colliding); if packaging leakage occurs, it should be immediately covered and absorbed with dry sand, and collected and transferred to a closed container to avoid the raw materials contacting the wet ground and causing agglomeration.
IV. Storage Optimization for Special Scenarios
Short-Term Storage After Opening
If the packaging is not used up after opening, secondary sealing is required: clamp the bag mouth with a sealing clip, or line the drum with a plastic bag and vacuumize it. At the same time, mark the "opening date" on the outer packaging, and give priority to using the opened raw materials to avoid quality degradation caused by long-term exposure.
Packaging Reinforcement During Transportation
Shock-proof materials (such as foam boards and bubble films) should be filled in the outer packaging during transportation to prevent packaging from breaking due to 颠簸 (bumping); long-distance transportation should use containers or closed trucks to avoid rain or direct sunlight. In summer, the temperature in the truck should be controlled ≤30°C, and in winter, low-temperature freezing should be prevented (a thermostatic carriage can be equipped).
The storage and packaging of zinc gluconate raw materials should focus on "moisture-proof, light-proof, and pollution-proof". By selecting inert barrier materials, controlling the temperature and humidity environment, and standardizing identification management, the physicochemical properties (such as solubility and purity) and biological activity (such as the absorption and utilization rate of zinc ions) of the raw materials during storage are ensured to be unaffected. In actual operation, combined with the Good Manufacturing Practice (GMP) or food-grade raw material storage standards, the inventory raw materials should be sampled and inspected regularly (such as appearance, moisture content, and heavy metal indicators) to ensure their application safety in food, medicine, and other fields.
