PBST Buffer (PBS with Tween 20)
Introduction
PBST or PBS-T (phosphate-buffered saline with Tween 20) is PBS buffer with a detergent such as Tween 20 or Triton X-100 (CSH Protocols recommends Tween 20). Detergent concentration can vary depends on requirement but generally vary from 0.05 – 2% (CSHL Protocols recommends 0.05). We are giving composition based on CSHL protocols in the tabular form.
Applications
Used as a washing solution for:
- Western blot membranes.
- PFA (Paraformaldehyde) fixed samples.
- Microtiter plate wells in ELISA assays.
- Immunohistology.
Composition
| 1X PBS 500 mL | 1X PBS 1L | 10X PBS 500 mL | 10X PBS 1L | |
|---|---|---|---|---|
| Tween 20 to be added | 25 µl | 50 µl | 250 µl | 500 µl |
Table 1. Preparation of 0.05% (V/V) PBS-T buffer.
pH
Keep pH at 7.4 with HCl and NaOH.
Preparation
- Make 1X PBS buffer.
- Add Tween-20 as desired concentration.
- Swirl slowly until dissolved.
Storage
Store at room temperature. Keeping in lower temperature might lead to crystallization.
Points to be noted
- Tween 20 and Triton X-100 are viscous liquids. You will have to cut the narrow end of the pipette tip for easy aspiration.
- If you find pipetting still difficult, weigh the detergent (consider density for determining volume) and add PBS to it.
- Detergents make froth upon agitation. Swirl gently to avoid froth.
Reference
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