biochrom HB Ultrospec 7500, User Manual

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Ultrospec 7500 User Manual • 41 56 2050 REV03 • 90
Nucleic Acid Concentrations
Concentration = (A260 - A320) × Factor × Pathlength Factor × Units Factor × Dilution Factor
A260 is the absorbance at 260 nm.
A320 is the optional background absorbance at 320 nm.
Factor is the value defined within the application method parameters.
Pathlength Factor is based on the pathlength selected:
Selected Pathlength Pathlength Factor
10 mm 1
5 mm 2
1 mm 10
0.5 mm 20
0.2 mm 50
0.125 mm 80
Units Factor is based on the units selected:
Selected Units Units Factor
µg/ml 1
ng/µl 1
µg/µl 0.001
pmol/µl ACGT
Calculated from
nucleotide sequence*
pmol/µl User Defined +
* Calculated using method described by Ahnert and Patel (197, p. 272), specifically:
Molar Extinction
Coefficient (M -1 cm -1 )
= 15 200 × Number of A + 7 050 × Number of C+ 12 010 × Number of G + 8 400 × Number of T
The units factor is 1 000 000 ÷ Molar Extinction Coefficient (M
-1
cm
-1
).
+ The user defined coefficient for pmol/µl has to be 1 000 000 ÷ Molar Extinction Coefficient (M -1 cm -1 ).
Dilution Factor is the value defined within the application method parameters.
References:
Ahnert, P. and Patel, S. (1997). Asymmetric Interactions of Hexameric Bacteriophage T7 DNA Helicase with the 5′ - and 3′ -Tails of the
Forked DNA Substrate. Journal of Biological Chemistry, 272(51), pp.32267-32273.