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#1
Report 17 years ago
#1
Ok, so I thought we're meant to use a colorimeter. But that doesn't work coz in practise the ppt doesnt sink 2 the bottom. So how are we meant to measure the intensity of light that goes through the remaining solution. I can't do this!!! Please reply if you have any methods. Thanks!
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snake_n_shades
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#2
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#2
if you want to measure the absorbance of the remaining solution then filter off the remaining solution using filter paper........i think this will work but i'll have to check it next time i'm in the lab
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#3
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#3
Thank you! I think that would work. Either that or centrifuge it so that the ppt becomes a lump at the bottom. I'll put both methods in my write-up that way I've got a better chance of being right! Lol. Cheers.
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snake_n_shades
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#4
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#4
ok i was in the lab today.......heres what i found:

anyone thinking that denatured albumen gives a negative result on a protein test, think again. even fully denatured protein went a nice purple when i tested it

if you put it through filter paper it takes ages, and theres several problems:
1 - the filter paper absorbs the solution
2 - there is some water left over from the solution that the albumen has precipitated out of

i can see using a centrifuge might work, remember you get a change in volume when the albumen precipitates out, and there is still the issue of the water remaining from the albumen solution


i still think that a visual method is the easiest and most accurate!!
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#5
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#5
Ooooh thanks! So do you study this kinda stuff? U doin a biochem degree or sumthin?
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snake_n_shades
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#6
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#6
lol no i'm doin AS level biology!!!
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#7
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#7
Serious? U allowed to go into the labs whenever you want? U must have good equipment then! Wot school u in?
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snake_n_shades
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#8
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#8
yeah for the last week we've been allowed into the labs, even when other teachers are doing lessons, its been great

im at lancaster gramma
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#9
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#9
Thats so unfair! My skools useless my teacher wont even help me!! Sam x
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#10
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#10
i am so stuck on this essay. its in for 2moro. what should i write for my prediction?
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#11
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#11
You guys are very fortunate: I'm an external candidate taking these exams at an independent girls school. I've not been in a school science lab for a good many years, and am studying these subjects on my lonesome, outside of work. In short I'm a mature student who works in a hospital lab and studies outside of business hours. No wonder I'm exhausted.
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