1. What is the NEB DNA Concentration Formula?

The NEB (New England Biolabs) DNA concentration formula estimates nucleic acid concentration from absorbance at 260nm. This standard method provides a quick assessment of DNA quantity in solution.

2. How Does the Calculator Work?

The calculator uses the NEB formula:

Where:

• \( C \) — DNA concentration (μg/mL)
• \( A_{260} \) — Absorbance at 260nm (optical density)
• \( F \) — Conversion factor (typically 50 for dsDNA)

Explanation: The equation accounts for the linear relationship between UV absorbance and DNA concentration, with the factor adjusting for nucleic acid type.

3. Importance of DNA Concentration Calculation

Details: Accurate DNA concentration measurement is crucial for molecular biology applications including PCR, restriction digests, ligations, and sequencing.

4. Using the Calculator

Tips: Enter A260 reading from spectrophotometer and appropriate factor (50 for dsDNA, 33 for ssDNA, 40 for RNA). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why use 260nm for DNA measurement?
A: DNA bases absorb UV light most strongly at 260nm, making this wavelength ideal for quantification.

Q2: What are typical factor values?
A: 50 for double-stranded DNA, 33 for single-stranded DNA, and 40 for RNA.

Q3: When should A260 measurement be taken?
A: Using freshly diluted DNA in a clean quartz cuvette with appropriate blank correction.

Q4: Are there limitations to this method?
A: Less accurate with contaminated samples (e.g., protein or phenol contamination) which affect absorbance.

Q5: What's the ideal A260 range?
A: For best accuracy, dilute samples to A260 between 0.1 and 1.0.