Recipes/PFA

From Kimmel Lab Wiki

8% Paraformaldehyde for bone & cartilage stain

Ingredients	Location
PFA	Area M, door shelf – 2nd row from upper left
Sterile water	Area D, Shelf 3
1N NaOH	Area D, Shelf 2

Directions

MAKE FRESH ONCE A WEEK EVEN IF THERE IS SOME LEFT OVER.

USE GLOVES AND MASK

1. Heat 80 ml of sterile water in microwave ~30 seconds or on heat plate to 60 degrees Celsius. Check with PFA thermometer.
2. Measure 7.9 to exactly 8 g PFA using scale under fume hood; *Note: Turn off fume hood fan!
3. Add PFA to water along with 400 µl 1N NaOH.
4. Turn fume hood fan back on.
5. Using PFA stir bar, heat loosely covered with lid on heat plate at level 7.
6. Leave solution heating until JUST fully dissolved. (~20 minutes; watch carefully)
7. Add 20 ml sterile water and filter with 100 ml 0.2 µm disposable vacuum filter.
8. Let cool.
9. Check pH ( should be <pH 7.5); correct with 1N HCl if pH is over 7.5 (add 1 drop at a time to get within pH 7.0-7.5, don't add more than 400 µl total. If it's still too basic, start from scratch!)
10. Store at 4 degrees Celsius in 2 x 50 ml culture tubes, dated. Make fresh weekly even if there is some left over. Put PFA over 2 weeks old into "used PFA" bottle in fume hood.

• Note: Only use PFA measuring equipment and vacuum filter found under fume hood. Throw away all disposables in "Hazardous Solid" red bin. Rinse glass beaker well and put rinse water into the "used PFA" bottle in fume hood.