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Sodium Acetate, Anhydrous Powder, 1 lb

$76.00
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SKU: ZS0265-450
California prop 65
Description
  • What it is. This sodium acetate is the anhydrous (water-free) form, supplied as a white powder in a 1 lb size. It is the sodium salt of acetic acid, used to prepare acetate buffers, precipitate nucleic acids, and support many laboratory and industrial processes.
  • Chemical identity. Anhydrous sodium acetate (CAS 127-09-3, CH3COONa, 82.03 g/mol) melts at about 324 °C and dissolves readily in water. It is hygroscopic and absorbs moisture from the air, so keep it tightly closed.
  • Anhydrous versus trihydrate. Sodium acetate is also sold as the trihydrate, which contains three waters of crystallization and has a formula weight of 136.08. When following a recipe, use the formula weight that matches the form on hand, or the solution strength will be off by about 40%.
  • Acetate buffers. Combined with acetic acid, sodium acetate forms buffers effective from about pH 3.6 to 5.6, centered on acetic acid's pKa of about 4.76. Acetate buffers are used in enzyme assays, chromatography, electrophoresis, and protein work.
  • Nucleic acid precipitation. A 3 M sodium acetate solution adjusted to about pH 5.2 is a standard reagent for ethanol precipitation of DNA and RNA. The sodium ions neutralize the phosphate backbone, allowing the nucleic acid to precipitate when alcohol is added.
  • Other uses. Sodium acetate is used in textile dyeing; as a food additive and seasoning; as a mild alkali and buffering agent in industrial processes; in concrete sealants; and in reusable heating pads that rely on the crystallization of supersaturated sodium acetate solutions.
  • Storage matters. Because the anhydrous form absorbs moisture, exposure to humid air raises its water content and lowers the effective concentration of weighed portions. Keep the container tightly closed and store it in a dry place.
  • Related products. Pair sodium acetate with Lab Pro's Glacial Acetic Acid, ACS Grade, 500 mL to prepare acetate buffers, and check pH with calibrated buffers such as Buffer Solution pH 4, Red.

Technical Specifications

Chemical Name Sodium acetate, anhydrous
CAS Number 127-09-3
EC Number 204-823-8
Synonyms Sodium ethanoate, acetic acid sodium salt
Formula CH3COONa (C2H3NaO2)
Molecular Weight 82.03 g/mol
Form White, anhydrous powder
Melting Point About 324 °C
Water Solubility Freely soluble
Hygroscopic Yes; keep tightly closed
Buffer Range (with acetic acid) About pH 3.6 to 5.6
pKa (acetic acid) About 4.76
Trihydrate Formula Weight (reference) 136.08 g/mol
Grade Confirm on label
Package Size 1 lb

Applications / Common Uses

  • Acetate buffers: Prepares buffers between pH 3.6 and 5.6.
  • DNA and RNA precipitation: Prepares 3 M sodium acetate for ethanol precipitation.
  • Chromatography: Buffers mobile phases.
  • Textile and industrial processes: Acts as a mild alkali and buffer.
  • Teaching labs: Demonstrates buffers and supersaturation.

Storage, Handling & Shipping

Store tightly closed in a cool, dry place away from strong oxidizers and strong acids. Anhydrous sodium acetate readily absorbs moisture, so reseal the container promptly after weighing.

  • Incompatible materials: Strong oxidizers, strong acids, and nitrates.
  • Personal protection: Safety glasses, gloves, and dust control.
  • Spill response: Sweep up without raising dust and place in a closed container.
  • First aid: Eyes: rinse with water for several minutes. Inhalation: move to fresh air.

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FAQs

What is the difference between anhydrous and trihydrate sodium acetate?

The anhydrous form contains no water of crystallization and has a formula weight of 82.03, while the trihydrate contains three waters and weighs 136.08 per mole. Use the formula weight that matches your material, or solution concentrations will be off by about 40%. Check the label for the form.

How do I make an acetate buffer with sodium acetate?

Dissolve sodium acetate and acetic acid in water in the ratio that gives your target pH, using the Henderson-Hasselbalch equation with a pKa of about 4.76. Adjust the final pH with acid or base while measuring with a calibrated meter, then dilute to volume. Use deionized water throughout.

Why is sodium acetate used to precipitate DNA?

Sodium ions from sodium acetate neutralize the negatively charged phosphate backbone of DNA and RNA. When you add ethanol or isopropanol, the neutralized nucleic acid becomes insoluble and precipitates, allowing you to collect it by centrifugation and wash it. Protocols typically use 3 M sodium acetate at about pH 5.2.

Why does anhydrous sodium acetate clump?

Anhydrous sodium acetate is hygroscopic and absorbs moisture from humid air, causing particles to stick together. Absorbed water also lowers the effective concentration of weighed portions. Keep the container tightly closed and store it in a dry area to prevent this. Use dry spatulas when weighing.

Is sodium acetate hazardous?

Sodium acetate has low toxicity and is not generally classified as hazardous. It is used as a food additive in diluted form. In the lab, avoid creating dust, wear safety glasses and gloves, and confirm the classification on the safety data sheet for this product.