v********a
发帖数: 646 | 1 请问，absorbance of 1 unit at 260 nm corresponds to 40 μg of RNA per ml (
A260 =1= 40 μg/ml).
这个算式，是怎么得来的？
能不能给出原始的计算方法？
谢谢！ | s******y
发帖数: 28562 | 2 是测量出来的。不是算出来的。
【在 v********a 的大作中提到】
: 请问，absorbance of 1 unit at 260 nm corresponds to 40 μg of RNA per ml (
: A260 =1= 40 μg/ml).
: 这个算式，是怎么得来的？
: 能不能给出原始的计算方法？
: 谢谢！
| z*f
发帖数: 27 | 3 From Wiki:
Using the Beer-Lambert Law it is possible to relate the amount of light
absorbed to the concentration of the absorbing molecule. At a wavelength of
260 nm, the average extinction coefficient for double-stranded DNA is 0.020
(μg/ml)−1 cm−1, for single-stranded DNA it is 0.027 (μg/ml)&#
8722;1 cm−1, for single-stranded RNA it is 0.025 (μg/ml)−1 cm&#
8722;1 and for short single-stranded oligonucleotides it is dependent on the
length and base composition. Thus, an Absorbance (A) of 1 corresponds to a
concentration of 50 μg/ml for double-stranded DNA. This method of
calculation is valid for up to an A of at least 2.[1] A more accurate
extinction coefficient may be needed for oligonucleotides; these can be
predicted using the nearest-neighbor model.[2] | v********a
发帖数: 646 | |
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