That 230 peak is a phenol peak. 

My suggestions: 

1) Getting rid of the phenol peak - when you are spinning down make sure the elution doesn't touch the bottom of the column as you are lifting it.  If you are uncertain if this is happening, try spinning it down again to dry it after you empty the bottom basket.

2) Increasing concentration - try eluting in 30 ul of water, and then taking the purified RNA, putting it back into the spin column and spinning a second time.  This will increase the amount of RNA you get from the column without increasing volume.

Best luck,

Dave

speedvac, but keep in mind that by concentrating your RNA via speedvac also will concentrate any other compounds present in your sample.

try to remove as much as possible of ethanol while washing RNA. Ethanol might reduce considerably the 230 ratio but never dry completely RNA pellet cause it becomes difficult to dissolve in water. 

Hope it helps, 

Best,

Hamadi

Dear Jacob,

According to my experience I want to add some other suggestions:

1) Using TRIzol (LifeTech) gives higher concentration of RNA compare to many different kits (included miRNA isolation kits)

2) I would advice using less amount of elution buffer/water (starting from 25 ul) to increase concentration (as Wai suggested).

3) And on the other hand, you should consider that in serum there is less amount of RNA, but much protein. Thus, you should have an optimum protocol which you can also denaturate nucleoprotein complexes efficiently. Once, my friend advised to use co-precipitants, it might be helpful.

Hope it was useful for you,

Regards

Instead of using 100ul of water to elute RNA in one go, just use 50, 30 and 30 ul. That will increase your RNA concentration.

Also try to do the extraction with kit method rather than the manual method.

And yes, don't forget to process your sample as quickly as possible after harvesting.

All the best!