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.
