Sciencemadness Discussion Board
Not logged in [Login ]
Search the forums Search   Frequently Asked Questions FAQ   View member list Member List   Today's Posts Today's Posts   Forum Stats Stats Back to: sciencemadness.org
Sciencemadness Discussion Board » Engineering and Equipment » Reagents and Apparatus Acquisition » PH meter Go To Bottom

Printable Version  
Author: Subject: PH meter
axehandle
Free Radical
*****



Posts: 1065
Registered: 30-12-2003
Location: Sweden
Member Is Offline

Mood: horny

[*] posted on 28-1-2004 at 22:45
PH meter

Sorry for spamming, but is EUR60 cheap for a _new_ digital PH-meter?



My PGP key, Fingerprint 5D96 E09E 365D 1867 2DF5 C2FE 4269 9C19 E079 CD35

\"Verbing nouns weirds the language!\"
View user's profile View All Posts By User
Organikum
resurrected
*****



Posts: 2337
Registered: 12-10-2002
Location: Europe
Member Is Offline

Mood: frustrated

[*] posted on 29-1-2004 at 07:48


depends on the electrode(s) you get with the thingie and the amount of calibration liquids.



Irgendwas is ja immer
View user's profile View All Posts By User
axehandle
Free Radical
*****



Posts: 1065
Registered: 30-12-2003
Location: Sweden
Member Is Offline

Mood: horny

[*] posted on 29-1-2004 at 08:28


Don't know about the electrodes, and 100ml of calibrarion liquid costs almost as much as the meter itself.



My PGP key, Fingerprint 5D96 E09E 365D 1867 2DF5 C2FE 4269 9C19 E079 CD35

\"Verbing nouns weirds the language!\"
View user's profile View All Posts By User
chemoleo
Biochemicus Energeticus
*****



Posts: 3005
Registered: 23-7-2003
Location: England Germany
Member Is Offline

Mood: crystalline

[*] posted on 29-1-2004 at 08:57
Homemade Calibration Buffers

Wow, don't even think about buying them!!
You can make your own buffers, with a set pH, if you have the acid/base component of the buffer - i.e. Acetate and acetic acid, H-phosphate or H2-phosphate etc.
Then you need to know the pK of each, and then u use the Henderson Hasselbach equation to calculate the pH according to
pH = pKa+ log[A-]/[HA].

MUCH EASIER:

check
http://www.bi.umist.ac.uk/users/mjfrbn/buffers/makebuf.asp

There you can choose lots of differnent buffer conditions, and it calculates the required amounts of acid/base - and the pH is SET!!

Hence - don't even think about buying them for 100 euros :):)



Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
View user's profile View All Posts By User
axehandle
Free Radical
*****



Posts: 1065
Registered: 30-12-2003
Location: Sweden
Member Is Offline

Mood: horny

[*] posted on 31-1-2004 at 15:19


Thank you! I never considered making my own buffer solution.



My PGP key, Fingerprint 5D96 E09E 365D 1867 2DF5 C2FE 4269 9C19 E079 CD35

\"Verbing nouns weirds the language!\"
View user's profile View All Posts By User

 Sciencemadness Discussion Board » Engineering and Equipment » Reagents and Apparatus Acquisition » PH meter   Go To Top