From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 02/07/01-02:49:04 PM Z
Nick Makris wrote:
> ... do you have the relationship of drops to
> millileters or stated differently, how do you determine the correct amount
> of fluid to be dispensed.
No. Nze stated the .05 ml per drop, but that may work for water at
standard conditions and is a good estimate. However, I have measured
different drop sizes depending on the dropper and the solution (likely
due to differing surface tension interactions). Anyway I have found it
best to calibrate each dropper for each solution. Now this is not a
problem if the threshold amount of all solutions are well exceeded; some
wide tolerance can still work, but at the expense of wasting chemistry.
The best accountability is to measure volume in ml and not drops.
> ... It could be that the best way to determine where to
> make the mark on the dropper would be to take the dropper that you use
> successfully and drop drops into the 'to be marked' dropper. ...
That could certainly work. But again I caution that different solutions
may have a different number of drops per ml. So it is best to calibrate
to make sure the different solutions are measured accurately relative to
each other. In other words, calibrate all droppers with drops of the
same solution from the same dropper. The 1 ml syringes, accurate to .01
ml can be found at most drug stores and are inexpensive (and only one is
required).
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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