64 well tips?

David Johnston daj at nhm.ac.uk
Fri Apr 23 02:32:16 EST 1999

we use a Drummond sequencing pipette (0-3 ul) with reusable polycarbonate
taper tips,

0.2mm tip size is fine for 377 64

0.4 mm tip size is fine for a stretch 373 and 377 96. Infact, (a) I find it
quicker to load a 377 96 than a 377 64 as there is less risk of overspill
and so you can be a bit more vigorous with the loading (but I always flush
the intermediate wells after loading, using a p20 Gilson with a std "gel
loading" tip anyway)  (b) I know that the spacers on the 373 stretch are
0.3 but the tip seems to fit fine.

we just flush the tip once in the top buffer tank between loads and one tip
can last for several weeks, a huge saving (literally many thousands of
pounds per year) in budget over the duckbills.

3 tips (no pun intended):

(1) always have a beaker of hot dH2O handy to put the tip into if it gets
blocked (the air inside heats, expands and forces the blockage out)

(2) trim the wide end of the tip down so you have just enough length, once
on the pipette, for your maximum loading volume plus about 1cm. This
reduces the free air volume, makes pipetting quicker and makes you less
likely to damage the tip as the whole thing is more compact and so you are
working nearer the tube holding the sample

(3) The fine end of the tips can also be trimmed a couple of times with a
sharp scaplel blade or fine scissors if they get terminally bent, but as
they are very flexible, when you get used to them, this is rarely needed.

In the UK, these are supplied by Lazer Lab Systems of Sarisbury Green,
Southampton, the pipette is about 100 UK pounds, tips are about 1 UK pound.



David A. Johnston,
Secretary to the WHO Schistosoma Genome Network,
Biomedical Parasitology Division,
Dept. of Zoology,
The Natural History Museum,
Cromwell Road, London SW7 5BD, England, UK.
Tel: 0171-938-9297 (from outside the UK: 44-171-938-9297)
Fax: 0171-938-9297 / 9249 / 8754 (from outside the UK: 44-171-938****)
eMail daj at nhm.ac.uk


The  Biomedical Parasitology Division is a WHO Collaborating Centre for the
identification of schistosomes and their snail hosts.

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