A free online molecular biology calculator to help calculate the concentration of a nucleic acid solution (either DNA, RNA or oligonucleotides) from the optical density absorbance value measured by a spectrophotometer (using a wavelength of 260nm).
Instructions for DNA Quantification
- Follow the manufacturers guidelines for operating your specific spectrophotometer
- Dilute your sample as necessary in either water or TE buffer. TE buffer is best, to maintain a neutral pH
- Generally, blank the spectrophotometer using whatever buffer your sample is dissolved in.
- Measure optical density of DNA or RNA sample, enter absorbance value OD260 in the form below.
- Enter dilution factor. For example if you diluted 2µl of sample in 100µl of dH2O, the dilution factor would be 50.
- Enter volume of stock nucleic acid sample. for example if you had 1ml of DNA solution, enter 1000.
- Select strandedness of nucleic acid, are you measuring ssDNA, dsDNA or RNA?
- Click on Calculate!
- The results show total amount of nucleic acid in the sample along with the concentration per microlitre.
The Javascript behind this DNA calculator was originally written by Santiago Navarro and was to be found on the following url: http://www.geocities.com/CapeCanaveral/Lab/9965. I used this calculator often but during the summer of 2004, the page disappeared from geocities. I managed to save a copy from Google cache before it completely vanished and I've been using it for a while as a local file. Since then I have been meaning to place it back online but I've only now got around to it (Jan 2005!). I hope other people find this updated DNA concentration calculator useful. Any comments?
