What is the expected absorbance of a solution of DNA that has a concentration of 34.00 ng DNA/μL?

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To calculate the expected absorbance of a DNA solution, you can use the relationship between DNA concentration and absorbance at 260 nm, known as the Beer-Lambert Law. For nucleic acids, specifically DNA, the absorbance (A) can be estimated using the following formula:

\[ A = \epsilon \cdot c \cdot l \]

Where:

  • \( \epsilon \) (molar absorptivity) for DNA is approximately 50 ng/mL per absorbance unit.
  • \( c \) is the concentration of DNA in ng/mL (for DNA), and we typically convert ng/μL to ng/mL by multiplying by 1000.
  • \( l \) is the path length of the cuvette, usually 1 cm.
  1. Convert the concentration: \[ 34.00 , \text{ng/μL} = 34.00 \times 1000 , \text{ng/mL} = 34000 , \text{ng/mL} \]

  2. Now calculate the absorbance: \[ A = \frac{34.00 , \text{ng/mL}}{50 , \text{ng/mL}} = 0.68 \]

Therefore, the expected absorbance of the solution of DNA at a concentration of 34.00 ng/μL is 0.68.