# Quantification

*The delivered DNA oligonucleotide yield depends on several factors and may therefore vary considerably.*

## Concentration Measurement

The oligonucleotide concentration is determined by spectrophotometry as follows: An aliquot of the oligonucleotide solution is diluted 100-fold, and the absorption at 260 nm is measured and multiplied by 100 (A_{260}).

## Unit Definition

1 OD unit is the amount of oligonucleotide in 1 ml solution which exhibits an absorption value of 1 at 260 nm wavelength and 1 cm light path length. By taking into account the volume of water, in which the oligonucleotide is dissolved, the extinction coefficient and molecular weight of the oligonucleotide, the A_{260} value can be converted to OD units, concentration and yield. We use the following simple calculations:

## Molecular Weight

The molecular weight of the oligonucleotide is estimated as the sum of the following constants minus 61.96 (MW(PO_{2} ÷ H)).

## Concentration

The concentration (pmol/μl) is calculated as A_{260} divided by the extinction coefficient of the oligonucleotide. We estimate the extinction coefficient of the oligonucleotide as the sum of the contribution from the bases and use the following constants.

## Yield

The yield in OD units is equal to: A_{260} x volume in μl / 1000 μl

Molecular Weight | Concentration | |

dA | 313.21 | 0.0154 |

dG | 329.21 | 0.0117 |

dC | 289.18 | 0.0073 |

dT | 304.2 | 0.0088 |

dI | 314.19 | 0.0075 |

dN | 308.95 | 0.0108 |

Modification extinction coefficients, will be added to the equation.

## Information provided on the Vial Label

- Oligonucleotide number
- Oligonucleotide name
- First 12 bases from 5' end
- Lot number/Order ID
- Concentration in pmol/μl
- Shipping date
- Number of bases