Glycine USP Storage & Tank Compatibility

Storing Glycine USP? Start Here

Glycine USP is the pharmacopeial grade of the simplest amino acid, with the formula C₂H₅NO₂ and a molecular weight of 75.07. It is a white, odorless, sweet-tasting crystalline solid that dissolves freely in water to form near-neutral, low-hazard solutions. USP grade glycine is used in pharmaceutical buffers and irrigation fluids, parenteral and oral formulations, food and beverage processing, fermentation media, and personal care products. Because it is non-flammable as supplied and chemically stable, glycine poses minimal storage risk, and its main handling concerns are dust irritation and keeping the product dry and uncontaminated. For tank and equipment selection, the relevant behavior is that of a freely water-soluble amino acid that yields mild, weakly buffered aqueous solutions rather than an aggressive acid, base, oxidizer, or solvent.

Glycine USP in Polyethylene (HDPE and XLPE) Tanks

Polyethylene is an excellent material of construction for glycine USP service. Published polyethylene chemical resistance data rate amino acids, and glycine specifically, as fully resistant in HDPE and LDPE with little or no damage after sustained exposure across normal ambient temperatures. Aqueous glycine solutions are near-neutral and contain no oxidizers, aromatic or chlorinated solvents, ketones, esters, or anhydrides that would attack the polymer, so both HDPE and crosslinked polyethylene (XLPE) carry a Suitable rating for storage, batching, and dosing tanks. Specify a tank specific gravity rating appropriate to your solution concentration, use polyethylene or EPDM-gasketed fittings, and keep the tank closed to protect product purity. For elevated-temperature CIP or hot-fill steps, confirm the temperature rating of the tank wall, fittings, and gaskets, since polyethylene loses strength as temperature rises even where chemical resistance remains good.

Material compatibility at a glance

Glycine USP is a mild, water-soluble amino acid that is fully compatible with polyethylene (HDPE and XLPE), polypropylene, PVC/CPVC, and 316 stainless steel for storage, batching, and dosing of aqueous solutions. EPDM is the preferred elastomer; carbon steel is unsuitable for product contact due to corrosion and metal pickup.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Wear safety glasses or goggles and gloves; avoid generating or inhaling dust during transfer and weigh-out.
• Provide local exhaust or general ventilation when handling powder to limit airborne dust (H335 respiratory irritation).
• Treat the dry powder as a combustible dust; control ignition sources and avoid dust clouds.
• Keep containers tightly closed and store in a cool, dry place away from incompatible strong oxidizers.
• Use food or pharmaceutical grade wetted materials (HDPE, XLPE, PP, 316 stainless) and validated CIP to protect USP purity.
• In case of eye or skin contact, rinse thoroughly with water; follow the supplier Safety Data Sheet for first aid.

Common questions

Can glycine USP be stored in a polyethylene tank?

Yes. HDPE and XLPE are both rated Suitable for glycine. Amino acid solutions are near-neutral and chemically mild, and polyethylene resistance charts list glycine and amino acids as fully resistant. Choose a tank with a specific gravity rating that matches your solution concentration and use EPDM or polyethylene gaskets.

Is glycine USP corrosive to metals?

Pure dry glycine is not aggressive, but its aqueous solutions can promote corrosion and metal pickup in carbon steel, which is why carbon steel is unsuitable for product contact. Use 316 stainless steel or a plastic such as HDPE, XLPE, or polypropylene for wetted surfaces.

What are the main hazards of handling glycine USP?

Glycine is a low-hazard material with an NFPA 704 rating of Health 1, Flammability 1, Instability 0. The practical concerns are dust irritation to skin, eyes, and the respiratory tract (H315, H319, H335) and treating the dry powder as a combustible dust. It is non-flammable as supplied.

Which gasket and seal materials work best with glycine solutions?

EPDM is the preferred elastomer for aqueous glycine service and carries a Suitable rating. Viton (FKM) is generally serviceable in water based duty but EPDM is usually the better choice. Always confirm gasket ratings for any elevated-temperature CIP or hot-fill steps.