21 replies to this topic

[Golaso]

Hi all,

I'm new to this website and I found it helpful in reading some of the interested topics

just to mention that I started my undergrad research in purifying RNA mainly H69,

I really need some help in some of the calculations concerning O.D readings

So basically I ran a 1 mL reaction for 4-5 hours, centrifuge to remove any salts, do ethanol precipitation and disolve the pellet in dH2O.

then I take the O.D of the sample and I read it as let say it's 100 O.D at 260nm witha volume of 70 uL
now if I want to make the reading to be 20 OD (since i need to run it in a small 9 by 7 gel) how much of the 100 O.D sample should be taking and how much should i dilute it to.

If there is a website that you think would be helpfull to me to look at, please post it

I will be posting more question, cz I really need help with this as an undergrad

Thanks
Golaso

[pito]

If you need 20 OD, you simple need to dilute the 100 OD 5 times...

Its best to make a new post with questions like this.

[tical84811]

Wish i found this website 1 year ago when i first started in the lab. However i've found it now and so far the content is amazing!

[Divya Pothula]

Hello Everyone!

I am kinda confused with the dilutions.....
1.I need to make a 0.02% of Bromophenol blue (working solution) in a 5Xor 10X buffer. I made 5X buffer and then made a 2% firstly.
by adding 0.16 gm to 6.4ml 5X buffer (made 8ml).

Now I need to make a 0.02 or0.01 final dilution. How do i do this?

2. I know the final concentration of my RNA extracted. I need to know how much I am loading or using /ul. I get so annoyed calculating in terms of ug/ul.

Can someone help me please.

Thanks

[mdfenko]

c1v1=c2v2

concentration, in your case, is weight per volume. g/l=mg/ml=ug/ul. if you know the concentration then you know how much you are loading/ul.

[Divya Pothula]

Hi
Thanks for ur explanation. I kept myself cool and worked out....I could get the concentration and the loading amount too.

[jeanbaker]

I appreciate the clear explanation of this.