DESS (DMSO/EDTA/NACL) Protocol
Mirayana Marcelino Barros, Tiago Pereira, Alejandro De Santiago Perez, Hunter Powell, Jenna Brown
Abstract
DESS (DMSO/EDTA/NACL) protocol instructing how to make the solution for the preservation of samples.
Steps
Make 2L stock solution of 0.5M EDTA; if stock is already made, proceed to step 4.
Combine 372.24g disodium EDTA and 500mLdeionized water. Tip: Disodium EDTA is labeled PINK in the Bik Lab.
Add enough 5M NaOH to the solution to bring it to a pH of 8.0
Tip: NaOH is labeled GREEN in the Bik Lab.
Tip: In some cases, this can be as much as 500 mL. The EDTA will begin to dissolve around a pH of . 7.0.
Bring final volume to 2Lwith deionized water once all disodium EDTA has dissolved.
Prepare 2L DESS from 0.5M EDTA.
Combine 1L 0.5M disodium EDTA , 400mL Dimethyl Sulfoxide/DMSO , and 600mL deionized water in a 4000 mL Erlenmeyer flask.
Tip: 0.5M disodium EDTA is labeled YELLOW and Dimethyl Sulfoxide/DMSO is labeled ORANGE in the Bik Lab.
Put magnetic stir bars in the solution and place flask onto a hot plate. Turn the magnetic stirring function on and leave it at room temperature.
Add enough NaCl to saturate the solution: Add NaCl in 100g increments until 300g is reached, and then proceed to adding smaller amounts until salt is no longer dissolving. Solution should saturate with the addition of ~300-400g NaCl.
Tip: NaCl is labeled RED in the Bik Lab.
Tip: This step can take hours: BE PATIENT. There may be leftover salt residue once the solution is fully saturated.
