Product Overview
Sodium Metabisulfite ACS Grade is a white crystalline powder that functions as a strong reducing agent and oxygen scavenger across laboratory, water treatment, and industrial processes. Also known as Sodium Pyrosulfite or Disodium Metabisulfite, this inorganic salt releases sulfur dioxide in aqueous solution — the mechanism behind most of its working applications, from dechlorination to antioxidant preservation.
Alliance Chemical offers this product in sizes from 2 lbs through 50 lbs, scaled for both analytical laboratory work and production-volume operations. An SDS, TDS, and lot-specific COA are available with every order.
Why This Grade
The ACS Grade designation signals to procurement and QC teams that this sodium metabisulfite is sourced specifically for buyers whose workflows call for that level of analytical consistency. Laboratory analysts running titrations, QC leads validating oxidizing-agent concentrations, and R&D groups building reproducible protocols all specify ACS Grade because it narrows the variability window compared to technical-grade alternatives.
If your process is industrial-scale dechlorination or general reducing work where slight batch variation is acceptable, a technical grade may be more cost-effective. But where your results depend on reagent consistency — analytical chemistry, standardized test methods, or tightly controlled formulations — ACS Grade is the standard procurement choice.
Chemical Profile
Sodium Metabisulfite appears as a white crystalline or powder solid with a slight sulfur odor. In the presence of even trace moisture, it develops the characteristic odor of sulfur dioxide — a useful field indicator but also a reminder that sealed, dry storage matters. Its molecular formula is Na2O5S2 with a molecular weight of 190.11 g/mol (CAS 7681-57-4). The solid is denser than water at 1.4 g/cm³ and dissolves readily, with a solubility of 54% in water. It is noncombustible under normal conditions, but at high temperatures it can decompose to release toxic sulfur oxide and sodium oxide fumes. When mixed with water it forms a corrosive acidic solution — a property that drives many of its industrial applications but also dictates container selection and PPE requirements.
Industrial Applications
Sodium Metabisulfite earns its place in multiple industries because it is an effective, controllable source of sulfite ions and sulfur dioxide in solution.
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Analytical Reagent: In the laboratory, sodium metabisulfite serves as a reducing agent in titrations and quantitative procedures used to determine the concentration of oxidizing agents. ACS Grade material is the typical specification for these workflows because analytical results depend on reagent consistency.
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Water Treatment: Municipal and industrial water operators use sodium metabisulfite as a reducing agent to neutralize residual chlorine in treated water before discharge or downstream processing. The reaction is fast and stoichiometrically predictable, which makes dosing straightforward at scale.
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Food Preservation: In food and beverage processing, sodium metabisulfite acts as an antioxidant and antimicrobial agent, preventing oxidation and spoilage during production and storage. It is widely used in winemaking, dried-fruit processing, and juice stabilization.
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Photography: Photographic developers have long relied on sodium metabisulfite as a reducing agent in film and print development baths, where it controls oxidation of the developing agent and extends bath life.
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Textile Processing: In dyeing operations, sodium metabisulfite functions as a reducing agent to strip or modify dye uptake, improving color control and fabric quality during wet processing.
Handling & Storage
Sodium Metabisulfite carries a Danger signal word (per the product's GHS classification) with hazard statements H302 (harmful if swallowed) and H318 (causes serious eye damage) (per the product's GHS classification). These classifications govern your PPE selection and storage design.
PPE: Wear chemical-splash goggles and chemical-resistant gloves at minimum. In dusty or poorly ventilated conditions, use respiratory protection rated for sulfur dioxide, since the powder liberates SO₂ on contact with moisture — including humidity in the air.
Storage: Store in a cool, dry area in tightly sealed HDPE or other compatible containers. Sodium metabisulfite is moisture-sensitive and prone to oxidation; exposure to humid air degrades the material and generates sulfur dioxide gas. Keep away from strong acids, strong oxidizers, and incompatible metals. Ensure adequate ventilation in the storage area to prevent fume accumulation.
Spill response: Avoid generating airborne dust. Sweep or vacuum dry spills carefully. Do not flush with water in a confined area — the acidic solution formed can corrode metals and release additional SO₂.
Hazmat & Shipping
Sodium Metabisulfite is not regulated as a hazardous material for transport under DOT (per 49 CFR 172.101) — it carries no UN number, no hazard class, and no packing group assignment. This simplifies carrier acceptance and paperwork relative to many other industrial chemicals.
All shipments from Alliance Chemical's Taylor, TX facility include proper documentation. Shipping and handling guidance for this product has been reviewed by Andre Taki, DOT Hazmat Specialist.
Documentation
A Safety Data Sheet (SDS) in English ships with every order. A Technical Data Sheet (TDS) detailing the product's specifications and recommended handling is also available. For buyers who require incoming-material verification, a lot-specific Certificate of Analysis (COA) is available — request it at the time of order so it ships with your material.
Why Buy from Alliance Chemical
This sodium metabisulfite is offered in pack sizes from 2 lbs for bench-scale analytical work up to 50 lbs for production runs — with SDS, TDS, and lot-specific COA documentation available for every shipment. Alliance Chemical has been distributing industrial and laboratory chemicals since 1998, serving over 50,000 customers from our warehouse at 204 S Edmond St, Taylor, Texas. Product pages and shipping guidance are reviewed by Andre Taki, DOT Hazmat Specialist.
