# am I using the right units?

• Oct 15th 2012, 04:59 AM
blue00
am I using the right units?
Hello,

Probably a really simple question for any mathematician, but not so easy for the confused biochemist needing help.

I'm looking at the concentration of a compound produced by a microbial culture that is measured in ng L -1. I want to express the concentration of this compound relative to the dry weight of this culture (DW) which I have measured in mg L-1. Does this mean my units will be ng L-1 mg L-1 DW? Or can it be simplified to ng mg L-1 DW?

Any help would be much appreciated! Thanks
• Oct 15th 2012, 06:23 PM
chiro
Re: am I using the right units?
Hey blue00.

If you are expressing one thing relative to another you usually are looking [a]/[b] where [a] is the units for a and [b] is the units for b.

So a relative to b unit wise is [a]/[b] = m/n or mn^(-1). If m can be written as a function of n (or vice-versa) then this can be simplified.
• Oct 19th 2012, 04:15 AM
abhishek009
Re: am I using the right units?
yes i also want to say the same thing.

thanks
packersm
• Jun 22nd 2013, 03:54 AM
athin
Re: am I using the right units?
very nice information. thanks a lot for this.

thanks
99th