Where Can I Find Detailed Information on Conway Microdiffusion Analysis?

[~christina~]

I really really need information on Conway microdiffusion analysis.
I know that there is a book but I can't find it and is that the only source of information on this technique? I have looked in my analytical chemistry books and there is NOTHING on it, in there.
I'm going to do this experiment but I cannot find out the, principles behind the method.
I read some journal articles but they just refer to the book.

I know that titration is needed but, why is also a mystery. I do know, from what I've read that the outer ring of the conway dish has a chemical placed into it, and that, that one diffuses into the middle well, which contains fixant chemical (I think that's what it's called), then the fixant is analyzed in the spectrometer. (This may be wrong, so if it is, please correct me)

If someone knows somewhere online, where I can find info on this, please link me to it. (I can't do the experiment unless I know what is happening and what is this, "conway microdiffusion analysis")


Thank you.

 

[Borek]

Not much, but hopefully better then nothing.

http://www.biochemj.org/bj/059/0134/0590134.pdf

 

[~christina~]

Not much, but hopefully better then nothing.

http://www.biochemj.org/bj/059/0134/0590134.pdf

I found that one already. I figured that was the best one I could find and it didn't explain why the solution was titrated. Thanks anyhow, Borek.

 

[sharif_k]

Hello everyone, I work in a vinegar plant and I used the following procedure to determine ethanol percentage in fermented molassus. I have added some pretext. Hopefully this will help you understand the know-how of this particular procedure -
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Determination and Estimation of Ethanol: Conway Method
Ethanol was determined by Redox titration. In this method ethanol is oxidized to ethanoic acid when ethanol react with excess of potassium dichromate solution (0.05 N) and un-reacted dichromates is then determined by adding potassium iodide (50% KI) solution which is oxidized by the potassium dichromate. Potassium iodide reacts with potassium dichromate and iodine. Then the iodine is treated with a standard solution of sodium thiosulphate (0.1 N). The titration reading is used to calculate the ethanol content after fermentation. One ml Fermented solution was diluted up to in 250 ml, 500 ml and 1000 ml distilled water and took one ml diluted solution as a sample. A Conway unit is used for ethanol determination by this procedure. One ml potassium dichromate was placed into the Conway unit center and sample was placed around the centre. The Conway unit was then covered by a glass plate for 24 hours for reaction. The water and ethanol slowly evaporate, come in contact with Potassium dichromate and then oxidized. More ethanol evaporates until eventually all the ethanol from the fermented dilute solution had left the sample and reacted with the dichromate. One Conway unit was used as a blank and in that unit 1 ml distilled water was used as a sample.
Alcohol analysis:
1. Conway unit center (1 ml 0.05 N potassium dichromate solution)

2. Round (1 ml sample)

3. Reaction complete within 24 hours

4. Conway unit centre (50% KI solution 0.5 ml +1-2 drop soluble starch)

5. Microburate (0.1 N sodium thiosulphate)

6. Titration

7. Colorless

Titration reading:
Percentage of Ethanol = ((TR of blank sample – TR of FS)× 11.5 × 0.1 × DF × 100)/(0.793 × 1000)
= Alcohol percentage gm/100ml
Where, Density of Ethanol 0.793 g/ml
Volume of sodium thiosulphate used: 11.60 cm3
DF – Dilution Factor
FS – Fermented solution
TR – Titration Reading

 

[LudusRex]

Conway microdiffusion analysis is a technique used in analytical chemistry to measure the concentration of a substance in a solution. It involves the diffusion of a substance from a solution into a surrounding medium, followed by analysis of the resulting change in the medium. The method was first described by R. J. Conway in 1962 and has since been used in various fields, including environmental analysis and pharmaceutical research.

The main source of information on this technique is the book "Conway Microdiffusion Analysis" by R. J. Conway. However, there are also journal articles and online resources available that discuss the principles and application of this method.

In Conway microdiffusion analysis, a sample solution is placed in a well in the center of a dish, and a chemical is placed in the outer ring of the dish. The chemical in the outer ring diffuses into the sample solution, causing a change in the sample solution. This change is then measured using a spectrometer to determine the concentration of the substance being analyzed.

The use of titration in this technique is to ensure that the concentration of the substance in the sample solution is within the range that can be accurately measured by the spectrometer. This is because the amount of diffusion that occurs is proportional to the concentration of the substance in the sample solution.

I recommend consulting the book by R. J. Conway for a thorough understanding of the principles and application of Conway microdiffusion analysis. Additionally, you can also refer to journal articles and online resources for further information and clarification on the method. I hope this helps in your experiment and understanding of this technique.