Quantification of Nucleic Acids
To determine the nucleic acid concentration in solutions the absorbance at wavelength 260 nm (A260) is used. The following function, derived from Lambert-Beer‘s Law, is applied:
Concentration [ng/μl] = Absorbance (260 nm) x Factor
(with Factor = Sample Specific Factor x Virtual Dilution Factor)
The Sample Specific Factor represents the specific absorbance for example of a sample of 50 ng/μl dsDNA that gives a reading of 1 Abs (A260), measured with an optical light path of 10 mm inside a standard cuvette. Due to the optical light paths of the TrayCell of 0.2 mm or 1 mm, additionally, a Virtual Dilution Factor of 50 or 10 must be taken into account.
For the different types of nucleic acid solutions the average dynamic range of the absorbance relating to the concentration (ng/μl) results as follows (depending on the lightpath):
| 1 mm lid, (Virtual Dilution Factor of 10) [ng/µl] * | 0,2 mm lid (Virtual Dilution Factor 50) [ng/µl] * | Measurement range [ng/µl] * | |
| dsDNA | 13 – 850 | 63 – 4250 | 6 – 8500 |
| ssDNA | 9 – 629 | 46 – 3145 | 5 – 6290 |
| ssRNA | 10 – 680 | 50 – 3400 | 5 – 6800 |
| Oligo | 8 – 561 | 41 – 2805 | 4 – 5610 |
| * typical absorbance, measured with an ordinary spectrophotometer | |||