1. What is NEB dsDNA Concentration?

The NEB dsDNA concentration calculation estimates the concentration of double-stranded DNA based on absorbance at 260 nm (A260). This is a standard method for quantifying DNA in molecular biology.

2. How Does the Calculator Work?

The calculator uses the NEB formula:

Where:

• \( C \) — DNA concentration (μg/mL)
• \( A260 \) — Absorbance at 260 nm

Explanation: Double-stranded DNA has an extinction coefficient of 50 (μg/mL)^-1cm^-1 at 260 nm.

3. Importance of DNA Concentration

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

4. Using the Calculator

Tips: Enter the A260 reading from your spectrophotometer. The value must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: Why multiply A260 by 50?
A: This conversion factor is based on the extinction coefficient of double-stranded DNA (50 μg/mL for 1 OD at 260 nm).

Q2: Is this accurate for ssDNA or RNA?
A: No, single-stranded DNA and RNA have different conversion factors (33 and 40 respectively).

Q3: What is a typical A260 value for DNA?
A: Pure DNA typically has an A260/A280 ratio of ~1.8. Values outside 1.7-2.0 may indicate contamination.

Q4: How should I measure A260?
A: Use a spectrophotometer with DNA dissolved in TE buffer or water. Blank with the same solution.

Q5: What if my DNA is very dilute?
A: For low concentrations (<5 ng/μL), consider fluorometric methods like Qubit for better accuracy.