cheap pH Meter experiences

[Mega [Andreas Stuermer]]

Hi guys! 

I want to do some enzyme chromatography. Now to elute or bind proteins to the column material you need certain pH values. 

I was basically wondering if a cheap pH meter will do (and, what is cheap). There are some for 12-23$ on Amazon, alledgedly with "good" accuracy. I immagine that the proteins will still elute from the column if the pH is actually 4.05 instead of 4.00 - maybe just a bit worse yield? 

I would rather not mess around and invest 100-200$ in one that will master the job with excellence. But then - maybe it comes from the same chinese factory and isn't better in any way... 

Any recommendations? Would be extremely appreciated! 

[Nathan McCorkle]

I would guess a good keyword/phrase to look for would be something
like "temperature compensated"... lots of electronics are temperature
sensitive, and will vary with temperature. As such, compensating is
possible, at the expense of more electronic components and engineering
time.

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-Nathan

[MC]

I had posted a reply to a relatively recent post here asking about the cheap ph meters from China (which are identical to many on Amazon). I bought one for about $5. Unfortunately I don't have any instrumentation to truly test the accuracy but I can say that testing some "standard" solutions with an expected pH value and comparing with pH paper, it's accurate enough for plant tissue culture. I occasionally double check with pH paper and it hasn't been off yet.

[Blair Robinson]

From my experience in the home beer brewing community, the prevailing advice on inexpensive pH meters is to skip the <$50 ones and spend a little more for something more reliable that will last a bit longer.  Two of the most recommended meters are as follows and there is a nice little summary on the Milk the Funk website here: http://www.milkthefunk.com/wiki/PH_Meter#Recommend_pH_Meters

http://www.hach.com/pocket-pro-ph-tester-with-replaceable-sensor/product?id=17990686211

http://www.milwaukeetesters.com/MW102.html

[Mega [Andreas Stuermer]]

Thx!! Stupid question - will a brewing pH meter work coreectly with HCl+KCl+etc.?

Maybe it is optimized for organic acids?

Shouldn't do, right? The H+ conc should be measured regardless?

[Mega [Andreas Stuermer]]

[Blair Robinson]

That's right, my understanding is that both of those recommended meters are general purpose instruments and wouldn't be specific to brewing or any other application in particular.

Cheers,

Blair

[Niek D'Hondt]

We bought this one for our lab and it's pretty good. Not in the 12-23$ range you are looking, but still worth considering.

http://www.conrad.com/ce/en/product/1305330/Greisinger----GPH114