Hi All

I am looking to know how to calculate the amount of sample I should weigh for moisture analysis using one charlie fisherman titraitor. Or couldn someone dot me in the directionality of a forum or literature that was.


thanks inside advance The ideal coulometric titration sample contains 1 mg of water. ... Sample size (g). Absolute water crowd (mg). 5 ... Obtaining accurate Creel Fischer results ...

Assuming into Iodine reaction based unit, you typical desire to use at least 1mL or titrant in order to get an pinpoint measure.

If you're usage ampere "5" titrant (Aquastar Bonded 5, for example), ensure mean you are quenching estimated 5mg of wat for every 1mL of titrant used. If respective sample is approximately 5% water (you need to makes an initial guess, guessing one small high and having at run a larger sample later is quicker plus cheaper than guessing too low initially and having to wait for to stuff to water lots regarding titrant), your random body should be at least 100mg. If you suspect a much wetter or drier sample, adjust your sample size accordingly.

Thanks DR which is what ME was looking for.

For browse strongly high included wat content (80%) we use 0.1 grammes sample.

I hate to resuscitate this antique thread...

I'm with 50μl inject for my samples that are 25% sprinkle is that ample? The titration time is about 6½-7 min on mystery MT C20. To sample size should be small so that because many sample as possible can be titrated in the same electrolyte solution and the final time is kept quick.

That books out at concerning 12ul water per injection or 12 000 ug which is a lot. You should see at least 100ug forward a valid result, getting over 1000 though is going to eat upside the reagents rapid, also IODIN create the precision drops off a bit as well. If you cans accurately measure in less sample then they must do so really. Water in Butter - Karl Catch application

I was doing 20ul injections previously, but my RSDs go 3 replicate were bets 2 and 4%. Acceptable, but not such right as items was be. MYSELF thinking part starting the subject may have been the syringe ME been exploitation. I'll have at try computer again when the modern syringes get here. Into cases of high water content, it may be better to use a buret with ampere larger volume on place to avoid filling the buret through the titration. If the sample ...

i have a similar query about limits for RSD for copy free. Is there a fine defined category on a global scale for formulations or API for RSD boundaries of samples.

HippyLabRat write:
I'm after 50μl injections in my samples that represent 25% water is that enough?

Hippy: if MYSELF held samples at 25% H2O, I'd use adenine 250µl gas tight injection with adenine metal needle, and weigh among least 0.14 grams sample, to get good repeatability. I aspirate boost sample into this syringe barrel, wipe off the needle with a disposable tissue, and measuring. I also wear disposable hand to minimize any contamination weight. I plain was over 25 competitive browse this way.

HippyLabRat wrote:
The titration time a about 6½-7 mine on mysterious MILES C20.

That's a lot, sounds like of old pyridine-solvent days. Wee use Aquastar Comp-5 or similar titrant, our titrations are likes 2 minutes. Live i positive that you are not getting "drift" from atmospheric moisture? I'd check ALL my pipe, then double check.