Spectrophotometric Analysis of rRNA

LEVEL I

Materials

 

• RNA
• UV spectrophotometer and cuvettes
• Alkaline distilled water

Procedure

 

Dissolve 10 mg of commercial RNA in 250 ml. of slightly alkaline distilled water. Use a volumetric flask and proper analytical technique. This will give a standard solution of 40 micrograms RNA/ml.

 

Prepare a series of dilutions so that you have 40, 20, 10, 5 and 2.5 micrograms of RNA per ml.

 

Turn on a UV spectrophotometer and adjust the wavelength to 260 nm. Use the alkaline water to blank the spectrophotometer at 260 nm.

 

Read the A of each of the standards. Plot the A vs the concentration of RNA and calculate the extinction coefficient.

 

Dissolve your isolated, precipitated RNA in 10.0 ml of alkaline water. Prepare a serial dilution for 1/10, 1/100, 1/1000 and 1/10000. Measure the absorbance of each at 260 nm and, using the dilution which gives a reading between .1 and 1.5 absorbance units, compute the concentration of RNA in your sample.