Eppendorf BioPhotometer - Manual (Page 17)

59
5 Operation
5.2 Measuring nucleic acids
This description is valid for the following methods:
– dsDNA
– ssDNA
– RNA
– Oligo
Call up method
Calculation
The factory-set factors are those which are normally used
with nucleic-acid methods for the conversion of
UV absorbance into concentration (in this example: 50). The
factors can be changed using the
key (see
"Programming"). The number of decimal places of the result
is determined by the number of decimal places of the
programmed factor.
If a unit of concentration other than µ g/mL is selected (e.g.
µ g/ µ L), the BioPhotometer converts the factor internally in
order to produce the correct result.
Measuring solutions with absorbances lower than app. 0.02
to 0.03 A
260 (corresponds to a DNA concentration of app. 1.0
to 1.5 µ g / m L ) should not be used. This is because with such
low absorbance, disturbances such as small particles, micro-
bubbles or turbidity have a great deal of influence upon the
measuring result and often lead to unreliable results.
Measuring procedure
Blank measurements remain stored until the date changes.
If a blank has already been measured on the same day, the
BioPhotometer offers the following in the last line of the
display after method call-up:
–
To measure a new blank or
– To measure a sample directly and to use the stored blank.
If no blank has been measured on the same day, the
instrument will only allow blank measurement.
Measure blank
7
dsDNA
d s D N A
P RO G R A M M E D FAC TO R :
1 A
2 6 0 = 5 0 . 0 µg/mL
Blank Sample or
Parameter
Blank
d s D N A B L A N K
0 . 0 0 0
A
Blank Sample or
05_Bedienung_e.fm Seite 59 Dienstag, 21. Februar 2006 10:09 Uhr