Sodium Metabisulfite - ACS Grade

Product Overview

Sodium Metabisulfite (Na₂S₂O₅) is a white crystalline powder that serves as a versatile reducing agent and antioxidant in various chemical processes. This ACS Grade material delivers high purity and consistent performance essential for demanding applications in analytical chemistry, food preservation, water treatment, and industrial processes. The product stability and low impurity profile support precise reaction control, enabling reliable sulfur dioxide release in solution for redox modulation and dechlorination capabilities. Typical assay ranges (98–100.5 wt%) and color parameters (APHA ≤ 5, typical 3) reflect strict quality control aligned with ACS and USP-NF expectations. With a molecular weight of 190.11 g/mol and a specific gravity near 1.50 at 20°C, the salt presents predictable handling characteristics across formulation workflows. The material is highly soluble in water, facilitating rapid mixing and aqueous-phase reactions while maintaining low residue after ignition, which supports clean downstream processing.

In addition to its core reducing properties, Sodium Metabisulfite acts as a protective agent against oxidation in sensitive analytical procedures and as a precursor for controlled sulfite generation in preservation systems. The ACS Grade specification ensures compatibility with pharmaceutical, cosmetic, and food contact environments where validated purity is required. The product's storage and packaging recommendations emphasize moisture control and inert handling to preserve potency and minimize degradation over the product’s shelf life, which is listed as 24 months when stored properly.

Key Properties

• Chemical Formula: Na₂S₂O₅
• Molecular Weight: 190.11 g/mol
• Appearance: White crystalline powder
• Odor: Slight sulfurous odor
• Solubility: Soluble in water
• Specific Gravity (20°C): 1.50 (typical)
• Residue After Ignition: ≤ 0.20% (typical 0.05%)
• Chloride (Cl⁻): ≤ 10 ppm (typical 5 ppm)
• Nitrate (NO₃⁻): ≤ 5 ppm (typical 2 ppm)
• Arsenic (As): ≤ 0.01 ppm (typical 0.005 ppm)
• Heavy Metals (as Pb): ≤ 1 ppm (typical 0.2 ppm)
• Iron (Fe): ≤ 0.5 ppm (typical 0.1 ppm)

Common Applications

• Food Preservative: Used to prevent oxidation and spoilage in various food products, leveraging controlled sulfite release for antioxidant protection and shelf-life extension
• Water Treatment: Acts as a reducing agent to remove residual chlorine and as a sulfur dioxide source in stabilization workflows
• Analytical Reagent: Employed in titrations and analytical procedures to determine concentrations of oxidizing agents and as a selective reductant
• Photography Developer: Serves as a reducing agent in photographic development processes requiring precise redox control
• Textile Industry: Used in dyeing and finishing processes to reduce color and improve fabric quality through controlled reduction

Safety Precautions

Handle Sodium Metabisulfite in a well-ventilated area, wearing appropriate PPE including gloves, goggles, and a lab coat. Store in cool, dry locations away from moisture and incompatible materials, using HDPE containers and ensuring containers are closed to minimize exposure to air which can promote oxidation and degradation. Maintain separate storage from oxidizers and corrosives, and ensure ventilation to prevent fume buildup in shelves and cabinets.

Follow SDS guidance for exposure mitigation and emergency response. In case of skin or eye contact, rinse thoroughly with water; for inhalation, move to fresh air and seek medical attention if irritation or symptoms persist. Ingestion requires rinsing the mouth and seeking medical advice. The product is designated as UN 3260, Corrosive solid, n.o.s., Class 8, Packing Group III for transportation; handle deliveries and transfers with caution to prevent spills and exposure. If a significant exposure occurs, refer to emergency procedures outlined in the SDS and contact poison control or local emergency services immediately.

Benefits

✔ High Purity ACS Grade – Meets or exceeds ACS Reagent Grade specifications with tight assay and impurity controls, enabling reliable performance in analytical and preservation applications.
✔ Predictable Reducing Agent – Provides controlled sulfur dioxide release for oxidative protection, dechlorination, and redox balance in diverse process streams.