1. Calculate the molar extinction coefficient (¥å260) of PNA oligomer. We use the values for the molar extinction coefficients of bases for this calculation.
¥å260 (A) = 13.7 mL/(¥ìmole x cm), ¥å260 (C)= 6.6 mL/(¥ìmole x cm),
¥å260 (G) = 11.7 mL/(¥ìmole x cm), ¥å260 (T) = 8.6 mL/(¥ìmole x cm)

Molar extinction coefficient of PNA is represented as the sum of those of individual bases that comprise the oligomer.
¥å260 = ¥Ò ¥åi x ni
(¥åi = molar extinction coefficient of base, ni = number of base)

2. Measure the absorbance (A260)of PNA solution at 260 nm.

3. Determine OD260 of PNA from the the absorbance (A260).

4. Determine the molar amount of PNA from OD260 & the molar extinction coefficient (¥å260).

¥ìmolar amount = OD260 ¡À ¥å260 (¥ìmole)