Quantifying minute amounts of DNA?

Dr. Richard V. Goering rgoeri at BLUEJAY.CREIGHTON.EDU
Wed Feb 23 11:47:38 EST 1994

On 23 Feb 1994, daj wrote:

> On 22 Feb 1994 14:12:49 GMT,
>   Helgi Briem Magnusson writes:
> >Hello Netters.
> >   Does anyone have a protocol for measuring the amount of
> >DNA when you only have a tiny amount available, i.e. too
> >little to visualize on an EtBr-agarose gel and too little
> >to give a reading at 280nm when diluted?
> 2 options that I know of, one expensive, the other even more so!
> (1) Invitrogen sell a "DNA dipstick" onto which you spot your DNA and 
> develop a colourimetric reaction you compare to a printed reference chart. 
> It claims to detect as low as 0.1ng/ul, takes about 10 mins and requires 1 
> ul of your template. We tried these a couple of years ago and had mixed 
> feelings about them but I vaguely recollect seeing that the present 
> version has been "improved".
> (2) Hoeffer sell a DNA fluorometer which measures fluorescence of 
> intercalated Hoecsst 33258 dye against a known standard. We also have mixed 
> feelings about this as we find it difficult to obtain reproducable results 
> (although we have not tried too hard). Detection is claimed to be from 
> 10ng/um to 5ug/ml and, with accessories, to detect 1ng total DNA.
> Either way, its a fiddle, good luck
> Cheers,
> David A. Johnston
> Dept of Zoology, The Natural History Museum, Cromwell Road,
> South Kensington, London SW7 5DB.
> (tel 071 9389297, fax 071 9388754, email daj at nhm.ic.ac.uk)


Before deciding to invest in a flourimeter for measurement of minute 
quantities of DNA, review the late 1993 thread regarding these 
instruments. They DO NOT WORK WELL (the Hoefer TK0100 in our laboratory 
does make an attractive paperweight, however). 

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