Dundalk Institute of Technology 6

Introduction to Nucleic Acid Measurement

• Techniques for measuring nucleic acid concentrations typically utilize wavelength measurements.

• Common wavelengths for the measurement of nucleic acids include:

  • 260 nm for nucleic acids

  • 280 nm for proteins

Methodology

• Equipment Used: UV-Vis spectrophotometer (referred to as "spec") adapted for smaller samples.

• Sample Preparation:

  • DNA samples prepared in a TE buffer (Tris-EDTA) or in ultrapure water.

  • Importance of properly blanking with TE to ensure accurate measurements.

Measurement Process

• Sample Volume: 2 microliters of the solution is placed on a pedestal for measurement.

• Concentration Assessment: The spectrophotometer reads the concentration based on absorbance at specific wavelengths.

  • Measurement will output concentrations in nanograms per microliter, which must be converted for analysis.

• Goal for Final DNA Digest: Aim for a final concentration of 1 microgram of DNA for the digestion process.

Calculating Concentration

• Seeking Concentration: Concentration values are interpreted from measurements to achieve the desired final output.

  • Significance of understanding the dilution required to reach the 1 microgram target.

Precautions in Measurement

• Bubble Presence: Ensure no bubbles are present on the pedestal as they can affect the readings.

• Sample Placement: Proper technique to drop the sample onto the pedestal to avoid air gaps.

Important Notes During Experiment

• Record measured absorbance (e.g., 438.2) for future reference.

• Ensure to note the group and relevant data for organized tracking of experiments.