uranium - 19-7-2006 at 05:37
i have to make a sensor to determine the percentage of sodium, and will be compare with the AAS later....see how much different both machine.
do anyone have an idea how to make it?
YT2095 - 19-7-2006 at 06:21
Sodium or Sulpher?
as said in another thread today about sodium, either a Spectrogragh or Ash test.
the spectrogragh you`re unlikely to be able to make, and the ash test isn`t something easily mechanised.
are you allowed to Burn a sample and test the gasses?
if you ARE then that would make things a little easier 
uranium - 19-7-2006 at 09:23
is sodium.....
well, i can do anything to the sample
evil_lurker - 19-7-2006 at 10:51
I would imagine that all the free sodium should be tied up into a soap molecule... you should be able to pull samples and titrate them easily...
unionised - 19-7-2006 at 12:20
"are you allowed to Burn a sample and test the gasses?
if you ARE then that would make things a little easier "
How come?
Most sodium compounds won't make it into the gases.
A titration or 2 sounds good to me. Perhaps in 2 stages to get free hydroxide then, with a different indicator, to get the soap like stuff.
YT2095 - 20-7-2006 at 00:34
the color shift in the flame to the 590nm range could be quantified against a stock sample as it burns, also the residue can be tested alot easier
with most of the volatile componants absent.
uranium - 20-7-2006 at 04:34
is that i can use electrochemistry method to do it.
emm...like i use i multiple electrod to be the sensor, and find out 2 electrod to be the standard of 0% and 100 %. when i get the result of voltage,
then i compare with the standard, and i get the result....
i try to make a low cost sensor
unionised - 20-7-2006 at 04:38
Something like this?
http://www.metrohm.com/products/downloads/brochures/pdf/na_I...
I think you will have problems making that cheaply.
uranium - 27-7-2006 at 16:03
well, i have been informed by my lecturer that i have to make the sensor which is never found in the lab...that means i have to make the sensor by my
own. i know this is hard to me, and, is that any information to make a electrode? i'm still undergraduate, have no information to make a sensor of
sodium.....thanks
not_important - 27-7-2006 at 16:25
You have a problem then, as the solution is what is used in that brochure - ion selective membranes. A conductivity measurement would give a very
rough idea, detecting both Na and K both of which are used in the transesterfication.
About the only other thing I can think of is a miniture spark or plasma spectrascope, using a linear CCD to read the spectum. You might have to add
known amounts of some noninterfering element to get a per-reading calibration.
unionised - 29-7-2006 at 08:27
I suspect conductivity would give an indication of water content rather than anything else.
A sulphated ash measurement dosen't take any complex equipment (and I'd not like to have to build my own flame photometer, but they pop up on ebay
soemtimes).
What sort of Na levels do you expect to find?
uranium - 29-7-2006 at 20:42
not specific, just want to make a sensor of sodium...
Ozone - 19-11-2006 at 15:19
Hello,
This looks like a rather old thread, but here goes:
Construct a block with two chambers. Between them mount some dialysis tubing which has been slit and opened flat. Close off the sides with plexi,
drill a hole in the ends (2 holes) of each chamber. Mount nipples or quick connectors into each hole. Run a slip-stream from your process through one
of the chambers back into the process. Run counter-current though the other chamber a pumped flow of deionized water (this will prevent scaling of the
cell). The outflow is run though a cell to which a conductivity probe has been added. Calibrate the conductivity meter against sodium (added) in your
process, and you should be off to the races (presuming of course that you are looking for residual catalyst in your products).
Hope this helps, better late than never,
O3