how would you make a 4% percent paraformaldehyde solution?

Work:
starting from 20% (diluted with PBS)
V1C1=V2C2
(100)(20)=(x)(4)
x=500
so add
496 ml of PBS (accounting for 4% paraformaldehyde) or would you add 500ml of PBS

Thank you

It depends on whether the percent is w/v or v/v.

if it is v/v, as I suspect, you are diluting the original by a factor of five, so add 4 parts water.

if you want 500 ml, add 100ml of 20 percent, and add 400ml water.

if you want 45ml, add 1 part of PBS (9ml) and four parts (36ml) water.

To make a 4% paraformaldehyde solution starting from a 20% solution diluted with PBS, you would need to follow these steps:

1. Determine the volume of the 20% paraformaldehyde solution you need to obtain a 4% solution. Use the formula V1C1 = V2C2, where V1 is the initial volume (unknown), C1 is the initial concentration (20%), V2 is the final volume (unknown), and C2 is the final concentration (4%).

2. Plug in the known values into the formula: (100)(20) = (V2)(4).

3. Solve the equation: 2000 = 4V2.

4. Divide both sides of the equation by 4: V2 = 500 ml.

Therefore, you would need to add 500 ml of PBS to your existing 20% paraformaldehyde solution (accounting for the dilution) to obtain a final 4% paraformaldehyde solution.

To make a 4% paraformaldehyde solution, starting from a 20% solution diluted with PBS, you can use the formula V1C1=V2C2, where V1 is the volume of the starting solution (20%), C1 is the concentration of the starting solution (20%), V2 is the desired final volume, and C2 is the desired final concentration (4%).

In this case, you want to calculate the volume of the starting solution (20%) to mix with PBS in order to obtain a 4% paraformaldehyde solution.

By plugging in the values into the formula, you have (20%)(100) = (V2)(4%).

To solve for V2, you divide both sides of the equation by 4%, giving you V2 = (20%)(100) / 4%.

Calculating this, you get V2 = 500 ml.

Therefore, you need to add 500 ml of PBS to the starting 20% solution to obtain a 4% paraformaldehyde solution.