check for "absolute" alcohol whether its absolute ?

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Arvind Singh Pundir
Arvind Singh Pundir's picture
check for "absolute" alcohol whether its absolute ?

how can i determine that the absolute alcohol i am using for the last step of dehdrating my specimen or slides is still ok for the use 
 h

 

heehawmcduff
heehawmcduff's picture
I found this site which

I found this site which describes some of the properties of commercial pure alcohol and also some chemical tests to determine if there are any impurities (such as water) in it.
http://chestofbooks.com/food/beverages/Alcohol-Properties/VII-Examination-Of-Commercial-Alcohol.html
I hope it's helpful.
 
Of course, I'm sure the duration of the blindness after drinking would also give you some idea ;-)

Kvachhani
Kvachhani's picture
pundir wrote:

pundir wrote:

how can i determine that the absolute alcohol i am using for the last step of dehdrating my specimen or slides is still ok for the use 
 h

 

it is batter to change the alcohol after usage in some slide dehydration than to check for the concentration of the alcohol, this can be depands on your tissue size and speciman no in one slide.

Arvind Singh Pundir
Arvind Singh Pundir's picture
Kvachhani wrote:

Kvachhani wrote:

pundir wrote:
how can i determine that the absolute alcohol i am using for the last step of dehdrating my specimen or slides is still ok for the use 
 h

 

it is batter to change the alcohol after usage in some slide dehydration than to check for the concentration of the alcohol, this can be depands on your tissue size and speciman no in one slide.

Hi
how can we know that now we cant use the alcohol any  more, we cant after every single dehdration change the alcohol is there any way that we can find out if there is water in the alcohol if yes  is it under optimal  limit for our  dehdration process

heehawmcduff
heehawmcduff's picture
That website that I posted

That website that I posted above suggests that:
Detection of water in "absolute" alcohol. - If the alcohol is shaken with anhydrous copper sulphate, the latter will become blue if the liquid contains water to the extent of about 0 8 per cent.

Guy Sovak
Guy Sovak's picture
I would change the Alchohol

I would change the Alchohol after 3 uses.
Guy

Arvind Singh Pundir
Arvind Singh Pundir's picture
thanks to all who shared

thanks to all who shared their precious time to give anwers , i also got one answere from from other source which i would like to share
thanks to JIM HALL
                   How can I determine whether used "absolute" alcohol is
still OK for the last stage of dehydrating specimens
or slides? 
Answer. 
Some people add anhydrous copper sulphate to the alcohols used
for processing tissues. It changes colour (white to blue) in the
presence of water, but this does not tell you if there is only a
tiny trace of water or enough to make the alcohol immiscible
with xylene.
 
  You may be interested in a simple method I developed for this
  purpose. My job is evaluating histology equipment for the
  Medical Devices Agency, (an agency of the Department of Health),
  and I was interested in trying to establish "carry-over" in
  processing and staining instruments. I started off by adding
  known dilutions of alcohol, drop by drop, to different amounts
  of xylene, my basic thinking being that water turns xylene
  milky, and if one adds enough of the diluted alcohol, the
  mixture eventually becomes clear again. From this I developed
  the following method:
 
  A measured 5 ml of xylene (the 5 ml is important) is placed in a
  50 ml glass beaker and placed on a black background. Using a 1
  ml plastic pasteur/transfer/dropping pipette, add the alcohol
  for analysis, drop by drop and keep count of the number of
  drops, until you can just detect a faint turbidity in the
  xylene. Carry on adding the alcohol to the xylene until the
  turbidity just clears, again taking note of how many drops were
  needed.
 
  Using known dilutions of alcohol, I was able to set up and
  standardise the method and obtain reproduceable results
  consistently. The method was not sensitive enough to detect the
  water in 99% or 98% alcohol.
 
  97% = 5 drops to turn xylene milky,  10 drops to clear the mixture
  96% = 4 drops to turn xylene milky,  14 drops to clear the mixture
95% = 3 drops to turn xylene milky,  34 drops to clear the mixture
  94% = 3 drops to turn xylene milky,  74 drops to clear the mixture
  93% = 3 drops to turn xylene milky,  83 drops to clear the mixture
  92% = 3 drops to turn xylene milky,  98 drops to clear the mixture
  91% = 3 drops to turn xylene milky, 140 drops to clear the mixture
  90% = 3 drops to turn xylene milky, 204 drops to clear the mixture
 
  You would have to initially set up your own range of standard
  dilutions with the particular alcohol used in your laboratory
  for the sake of accuracy. The 1 ml plastic
  pasteur/transfer/dropping pipettes, they can even be called
  pastettes, should be held vertically to standardise the size of
  the drops, and I tried to use the same brand each time.
 
  This is a simple method, and quick to do, although I should
  think the method would give the Biochemists the shudders. It
  could help to prolong the life expectancy of the alcohols used
  in processors.
 
  Jim Hall
 

Kvachhani
Kvachhani's picture
Really useful method, we will

Really useful method, we will definately try it.
Thanks & regards.

g a
g a's picture
Quite interesting to see that

Quite interesting to see that by mere addition in xylene you can trace out the water content of alcohol. But I had a little doubt.... xylene is miscible with alcohol but not water, and alcohols are miscible with water...... then is the method really sensitive enough as its mentioned.... I mean it says 3 drops of alcohol with water >90% purity and still you observe turbdity...
Has any1 Checked the reproducibility and authentication?

Guest (not verified)
Guest's picture
"how can i determine that the

"how can i determine that the absolute alcohol i am using for the last step of dehdrating my specimen or slides is still ok for the use."
Specimen for EM:I use 2 "100%" (really 98%) alcohol steps. I always use new alcohol in the second "100%" dehydration step. I use this next time in the first rinse.

For LM slides: I do the same thing. However, If the solutions become coloured or you notice that the alcohol falls to the bottom of the first histosol\histolene dehdration jar, change the solution. Use 2 histosol\xylene steps as well. Periodically check the wet slides to notice if there are any water bubble, if it gets to this sorry state your solutions are filthy and contaminated.

g a
g a's picture
I do not perform histolgy

I do not perform histolgy anymore but almost 3-4 years ago we use to keep 3 coplin jars of absolute alcohol and were just before
the xylene was prepared everytime afresh.
Its advisable to keep your jars closed for most of the time and constantly renew the first two of them too.
 

peter36
peter36's picture
Take some of the alcohol out

Take some of the alcohol out of the pot add some xylol to it. If it goes cloudy or milky then you have water in your alcohol. Also a possibility in processing some of the phosphate buffers in the nbf transfer though the alcohols this also will give a cloudy result if you add water to the alcohol possibly causing the formalin/phosphate pigment to present in your H@E sections.