Concentration of lambda dna

[Shiwali Goyal]

when i checked the qubit concentration of lambda dna (250microgram/microliter), the following readings occurs
in 1:100 dilution the readings are 0.246ng/µl, 0.236ng/µl, 0.244ng/µl
in 1:50 dilution the readings are 0.376ng/µl, 0.358ng/µl, 0.360ng/µl
Since in 1:50 dilution the readings should come almost double of 1:100
is there any fault in lambda dna as it is expired but its 1:100 concentration is perfect or any fault in qubit.
thanks in advance

[nucacidhunter]

250 ug/ul seems very high. 100x dilution of such stock should be 2.5 ug/ul and 50x dilution 5 ug/ul not the figures you have got. If you are using the same stock at the same time for both dilutions then concentration of 50x dilution should be twice as 100x dilution regardless of DNA quality. There could be some issues with pipette or pipetting.

[Shiwali Goyal]

Thank u so much