How to Dilute a Stock Solution

A. Why dilute?
Here are two situations that arise repeatedly in molecular biology labs:
1. You have a stock solution of some compound,  let’s say an antibiotic, and you want to add the compound to growth medium, at a much smaller concentration than the stock solution.
2. You have a tube of very concentrated bacteria, perhaps a billion cells per milliliter. You want to put a few hundred of them on a petri plate, so that the colonies that arise will be easily distinguishable.
In both cases, the way out of the problem is to dilute the original solution. If you work in a lab, you need to know how to do this.B. Methods of calculating dilutions
1. DILUTION FACTOR METHOD (fast, but requires inspiration): First, figure out the factor by which the original solution must be diluted. Second, divide the final volume of the desired solution by that factor, yielding the volume required of the original solution.
EXAMPLE: Suppose you need to make a 3 ml solution of growth medium supplemented with 50 µM of the antibiotic ampicillin from a stock solution of 5 mM ampicillin. The dilution factor is :
(5 mM) / (50 µM) = (5000 µM) / 50 µM) = 100
so you need to dilute:
(3 ml) / 100 = (3000 µl) / 100 = 30 µl
of the stock solution to a final volume of 3 ml.

Source : Oxford Laboratory Technology


3 Komentar

Filed under Bahan Kuliah

3 responses to “How to Dilute a Stock Solution

  1. kezedot

    I like u post
    graet blog

  2. Asslaamu’alaikum wr.wb, mas Nadjeeb..

    Dalam kesempatan yang ada (sibuk) hari ini, saya dengan hati yang tulus ikhlas ingin mengucapkan SELAMAT HARI RAYA IEDUL ADHA 1433H.

    Semoga takbir yang bergema membawa seribu keberkatan bersama-sama erti pengorbanan sebenar.

    Salam Iedul Adha yang mulia dari Sarikei, Sarawak.

  3. kezedot

    makasih y bang
    selalu merespon aku dan blue.hahaha

Tinggalkan Balasan

Isikan data di bawah atau klik salah satu ikon untuk log in:


You are commenting using your account. Logout / Ubah )

Gambar Twitter

You are commenting using your Twitter account. Logout / Ubah )

Foto Facebook

You are commenting using your Facebook account. Logout / Ubah )

Foto Google+

You are commenting using your Google+ account. Logout / Ubah )

Connecting to %s