Determination of Iodine (ppm) in Iodized Salt_A Complete Procedure (IS 7224_2006)
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- เผยแพร่เมื่อ 5 ต.ค. 2020
- Table salt (NaCl) is iodized frequently during processing into food grade form. So the determination of Iodine in ppm unit is a very important test parameter for knowing the quality of iodized table salt.
This video represents a complete procedure for the determination of Iodine content of iodized table salt sample.
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What an excellent demonstration. Regards from Brazil!
Does this work if the table salt used contains potassium iodide instead of potassium iodate?
hi. can you tell me how done your calculation, step by step?
You've added starch way too early. It should be added only when the iodine solution color had become very light, or when iodine concentration is very low. Adding way to early when iodine concentration is still high may delay reaction as availability of iodine is lessened due to stability of the starch iodine complex at high iodine concentration. This will lead to tendency of adding more titrant than necessary, leading to false positives.
Gordon Marilao, you are absolutely right. But we did many trials and did not get any significant difference. thats why in this video we showed as our regular practice. But ofcourse It's a very good practice to add starch a little bit later to get the accurate result. Thank you very much for your observations.
How can i standardize sodium thiosulfate by potassium dichromate Please
Take o.1 gm to 0.2 gm K2Cr2O7 in iodine flask and then add 100 mL dm water , add 3 gram KI then add 1: 1 HCl closed by cap with water seal place in dark place for 15 minutes then titrate against sodium thio sulphate when yellow colour appeared then add 5 ml 1% starch solution again titrate end point green.
Normality of Sodium thiosulfate. = 1000× weight of K2Cr2O7/ 49.04 x TV
I'm confused about how you get the initial burette reading where was it in the video I cannot see it. Please explain.
Iyan Salama, look at the video time 3.51 (in the Titration-Step). You can see a burette. Just look at the burette scale. It is showing that the solution taken in the burette is at the scale of 6.4. We have said to note this initial burette reading. This is the initial burette reading we used in the calculation.
Thanks for being with us.
Why you dont follow AOAC method?
I made a fresh potassium iodide solution but i found an issue as the color didnt turn yellow like what happened eith yours. It stayed for a whole day till it turned yellow. Is it okay to wait for it a day and use it? That will still make it work right?
You should not wait long during the sample preparation. Yellow color should be appeared during adding KI solution. Please try again following this video strongly. Thanks
If after adding the 2n h2so4 and 10% ki there is no yellow colour then what it may indicate..is it substandard
If yellow color is not developed, it indicates that the salt is not iodized.
If we do not get blue-boack colour near the end point with starch..but dark brown colour is observed..what does this mean?
Astha Jain, Colour developments after adding starch indicator can vary depending on the concentration of iodine in your sample. Dark Brown color observation indicates the low concentration of iodine in the sample.
Brown color also observed if the Starch solution is not freshly prepared.
Hello, i wanted to ask what do you mean with the factor in the cslcualtion part? Please answer as soon as possible. Thank you.😊
A factor comes during the method development. It is a fixed value of a calculation for a test.
@@MicroChemsExperiments can you explain more on how i know it?
How about spectrophotometric method of analysis. It is simpler and faster.
Gordon Marilao, Thank you so much for your suggestions. We will work on spectrophotometric method for the analysis very soon.
Hii!! thank you for the video. If IV flask is not available what do we do??
Use a flask with glass stopper to make the flask airtight
How much iodine is there in natural sea salt ?
Can you explain how to determine the insoluble impurities in fats and oils please?
I want this method in practice necessary for my lab
@@RonaldoRgftcut We will make video for insoluble impurities soon. Stay with us.
@@RonaldoRgftcutWe want to determine if the Iodine is tagged to a compound or not . How do we do that for that compound where the Iodine content that we are using is in nanograms
Does this method only application for salt sample fortified with iodate?
Yes.
How to make salt testing kit can you please drop a video of that.
Noted
@@MicroChemsExperiments How can i standardize sodium thiosulfate by potassium dichromate Please?
also will the normality of the sodium thiosulfate ever even change?
Preparation of 0.005N sodium thiosulfate is given in the reagent and chemical preparation step in this video. Yes, the normality of prepared sodium thiosulfate can be changed based on the environmental condition of shelf life.
You should standardize the sodim thiosulfate solution each time before use to get the accurate test result.
The factor was computed from the stoichiometric molar ratio of thiosulfate with respect to the iodine liberated, and said iodine with respect to iodate present in salt, and the subsequent conversion of said iodate content to its iodine equivalent in micrograms.
Gordon Marilao, Thank you so much for your kind explanation which is very helpful for us.
Can you show me how the number is coming which is 21140
How would you clean up the solution after the titration?
Use 30% nitric acid and soak the glasswares overnight. Then clean by soap and distilled water
How to prepare 0.005N KIO3 solution...can you please tell us
We will make video on it. Stay with us.
What is factor value?
can i use HCl instead of sulfuric acid?
No, you can't use HCl.
how much potassium dichromate? for the sodium thiosulfate solution
Watch this video: th-cam.com/video/X2KrBfnKw24/w-d-xo.html
How i analyse iodide in salt by 0.005 m thiosulphate titration ?
Same method
are we going to also need sulfuric acid?
What do you mean? Please speak in detais. Are you talking about the use of sulfuric acid in this test?? Yes 2N sulfuric acid is needed in this test. Thank you
Hi, what's the purpose of adding the 10% KI solution?
wiki---To a known volume of sample, an excess but known amount of iodide is added, which the oxidizing agent then oxidizes to iodine. Iodine dissolves in the iodide-containing solution to give triiodide ions, which have a dark brown color. The triiodide ion solution is then titrated against standard thiosulfate solution to give iodide again using starch indicator
That's right
In the final calculation, what does factor means?
Calculate factor of sample Dilution and molecular weight of iodine
why we are keeping the flask in a dark place? is that because iodine is unstable ???
Anything's Everything, thanks for your comment. The reaction mixture is kept in the dark before titration because light accelerates a side reaction in which iodide ions are oxidized to iodine by atmospheric oxygen which may give the false result.
How to standardize sodium thiosulphate? Is it necessary to standardize?
Shaheer Hassan, It's very important to use a standardized Sodium Thiosulfate Solution to get the accurate result. We didn't show the standardization procedure to shorten our video. We will prepare a video for standardization later. You can also find the procedure by searching on google. Thank you for being with us.
@@MicroChemsExperiments actually I am going to calculate the ppm of iodine following your video but without standardized solution. How much will it affect the results?
@@MicroChemsExperiments I'm actually not a chemistry guy and videos I've been seeing are pretty confusing. Your video is the easiest one. I have to perform it for a salt company but without standardized solution since it wasnt there in your video for 0.005N Sodium thiosulphate. Will it be near to the result?
Shaheer Hassan, The result will differ slightly without standardization, not much. You can carry out the experiment without standardization. But try to take accurate weight of sodium thiosulfate during the solution preparation.
Why after adding 1%starch, the colour did not become colourless but light blue-green?
Starch is an indicator which becomes blue green colour in the presence of iodine
Why did you add sulphuric acid?
Our reference standard method IS 7224 said so
Hi Mam... Can I do this for My MSC project??
Please suggest topics from phytochemistry or in fruits vegetables.... plzzzzz mam🥺
Please take help from a Botanists
We are still waiting the vedio related with the factor brother....
I'm sorry for the delay
How much ml is you're burette with stand ?????
Total volume of burette is 50ml.
where did normality come from?
Dear Iyan Salama, We used 0.005N sodium thiosulfate solution in the titration. Thats why the normality is 0.005N.
What is the dilution factor
No dilution factor is applicable here.
How much sodium thiosulfate do we need 10 ml?
Please take a look at the sample preparation.
Also what is the factor??
Iyan Salama, the factor of that calculation is given by IS 7224 & AOAC OFFICIAL METHOD who originally developed the method. It is just the calculation factor.
What is this factor in the calculation.....?
AU016 Payal Jaysukhbhai Satani, The factor in the calculation is originally given by the IS-7224 (who developed the method) to simplify the equation and they didn't publish any explanation for the factor.
What is ppm? mg per liter or mg per kg?
mg per litre
where did factor come from?? Please rrply this 😢
We followed IS 7224 Standard. We will make another video for these explanation and chemical reactions. Stay with us. Thanks
I want blank test
Sample ok but blank is not coming
Conduct the experiments with reagents only, don't add sample
Factor ka bata dain k kaise aaya
We will make video later explaining these stuff
ترجمة
Please write in english
How to transfer 0.005 N to morality?
How do you .005 Thiosulfate stander
Follow our video: th-cam.com/video/X2KrBfnKw24/w-d-xo.html
.005
@@muhammadyousaf-xj2cd For 0.005N, just convert the amount of chemicals needed for 0.1N.
Explain blank
Contains only reagents, not sample