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Oligonucleotide Concentration Formula:
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The Oligonucleotide Concentration Calculator estimates the molar concentration of oligonucleotides using UV absorbance measurements at 260 nm, the extinction coefficient, and the path length of the measurement.
The calculator uses the Beer-Lambert law formula:
Where:
Explanation: The equation relates the absorption of light to the properties of the material through which the light is traveling.
Details: Accurate oligonucleotide concentration measurement is crucial for molecular biology experiments, PCR reactions, sequencing, and various diagnostic applications where precise amounts of nucleic acids are required.
Tips: Enter A260 absorbance value, extinction coefficient, and path length. All values must be valid positive numbers. Standard path length for most spectrophotometers is 1.0 cm.
Q1: What is a typical extinction coefficient for oligonucleotides?
A: Extinction coefficients vary by sequence but typically range from 50,000 to 500,000 L·mol⁻¹·cm⁻¹ depending on length and base composition.
Q2: Why measure at 260 nm?
A: 260 nm is the wavelength where nucleic acids (DNA and RNA) have maximum absorbance due to the purine and pyrimidine bases.
Q3: How do I determine the extinction coefficient for my oligonucleotide?
A: The extinction coefficient can be calculated based on the sequence using the nearest-neighbor method or provided by the oligonucleotide manufacturer.
Q4: What is the typical concentration range for oligonucleotides?
A: Working concentrations typically range from nanomolar to micromolar levels, depending on the application.
Q5: Are there limitations to this calculation?
A: The calculation assumes the sample is pure and free of contaminants that might absorb at 260 nm, such as proteins or other nucleic acids.