It's truth that RU-vid have less video like this. I am assistant professor and some time professor also need this type of video for students to make them understand. I highly appreciate this one and will also show to students. Thanks for this.. and add many more like this 😊
😍👌Really appreciated one..So simplistic, but perfect👍..I always choose your videos as prime for my doubts..☺️also sub teacher also preferred it than other..and what might be the reason 😁.. Keep going 🤗
Iftekhar Kabir, Thank you so much for being with us. Lots of videos are yet to upload. AOAC methods are not publicly available in internet. We have AOAC official book which was purchased from AOAC officials.
In the calculation equation V1 is the volume of unused boric acid but we need the actual volume of used boric acid, so here you have use 30- V1 instead of V1
You should add the sample in the distillation vessel first and then add NaOH-solution. In the procedure shown on the video sample will react with NaOH-solution in open and it leads loss of nitrogen in form of ammonia. Also the receiving part should be under the liquid level.
Thank you for your findings. In AOAC, it is not said to keep the receiving part under the liquid level. And in this way, shown in this video, we get the expected results. This is because the loss of nitrogen is negligible. Anyways thanks for your suggestion.
@@MicroChemsExperiments It is obvious in this case that it has to be under liquid level. Also Kjelldahl method is pretty old and it has always been that way and finally it is stated in the AOAC 2001.11 in part "Distillation" "Place graduated 500 ml Erlenmeyer titration flask containing 30 ml H3BO3 solution with indicator on receiving platform, and immerse tube from condenser below surface of H3BO3 solution."
Can you help me calculate protein levels from the following data, I use the back titration method example: titration blank (NaOH: 0.1016 N) = 24.88 ml titration sample (NaOH :0.1016 N) = 22.17 ml sample weight = 0.1548 gr
This video is really helpful...but how we will get different factors of sample please tell...i mean how do you get to know the wheat grains factor is 5.70....how to calculate this factor of any raw material please explain
It is really helpful but i am unable to get results while testing for DOC . At time of digestion colour is not changing to green …. The sample gets totally black and after 2 hours or more than that unbale to get results… please suggest sir
Sir Please send me factor. Factor 1 which product Factor 2 which product Factor 3 which product. Example mentioned this product Maize, Rapeseed, fish meal, wheat flour, CGM,DDGS,Rice polish,DORB, sinking feed, floating feed,poultry feed,
So why did you use 0.1 as the Normality of HCl in your calculation and not the exact 0.0975 N from part 2? That you worked when you titrated HCl against NaOH using phenolphthalein ad your indicator?
Very smart... You are right. But I did not used the exact chemicals prepared in part 2 for protein titration. Rather I used 0.1N HCl and thats why I calculate protein using 0.1N. Part-2 video is prepared in different time, just to show you about the preparation.
Ok so quick question does the flask have to be a kjeldahl flask or can I use a volumetric flask if the first is unavailable? Also can I digest it on a soxhlet?
This calculation is derived from AOAC official method. So they used Kjehldahl's method and provided equation for calculation based on the difference steps of this method. So, please study about Kjehldahl's method to get proper explanation. Thank you.
Mauro Korn, thank you for your observation. I should use fume hood during handling H2SO4. We actually did it intentionally to shorten our video time, focusing only on the procedure. But normally in our lab we use fume hood.
@@MicroChemsExperiments , Today I will suggest and comment this video with my students. Considering the covid-19 pandemia, it is the best option to explain and to discuss practical procedures with our students. Thanks!
Another one question..if I need to prepare catalyst on my own, how much will be the potassium sulphate+copper sulphate+selenium dioxide that I need to use to make the catalyst?
From where did you drive the %N determination formula and why didn't you run the blank Though the formula in AOAC 2001.11 method is different from yours and they also subtracted the concordant reading of the Vs fron the Vb
Hadiqa Iqbal, Thank you for your questions and observations. First of all, we used %N determination formula from AOAC 2001.11 method which is modified in two places: 1. we didn't use burette reading of blank (Vb) because we didn't conduct any blank digestion in this experiment. 2. We used additionally Acid Factor (F1) which is not mentioned in AOAC book but used by the FAO method of ''Quality assurance for animal feed analysis laboratories, Page-90''. ***We didn't go for the blank digestion to simplify this method and we conducted several studies in our lab and found that there is no significant different in the protein result when we don't run blank digestion. ***Acid factor is only necessary when you want to titrate with any other acid rather than HCl. So, If you want, conduct a blank digestion along with sample (as it gives more accurate protein result) and substract Blank Burette reading from the Sample burette reading. You can also ignore the acid factor if you always use HCl in the titration. Thank you.
As far as i have studied if we are placing normality value of acid we don't add acid factor in calculations. As far as acid factor is concerned it always gets include into the calculations when we note molarity instead of normality Is that so ?
@@hadiqaiqbal795 As the acid factor is 1, so you can remove it from the calculation thus creating no differences in results. But if you use other acids like H2SO4, then you need to add acid factor in the calculation. In case of HCl, no need to use and Factor for Acid.
Very detailed video! One quick question, can I know if I can use this method for liquid sample? How the method will be when I want to measure the weight as my sample is liquid?
Yes. This method is applicable for liquid sample also. You can take 2g of liquid sample in a glass beaker first. Then transfer the weighted liquid sample from breaker to digestion flask quantatively washing with 20 ml sulfuric acid and add catalyst & heat the digestion flask to digest your sample in presence of acid and catalyst.
Can I get limitations. Also tell what are the precautions need to take to get accurate result. I mean during digestion, distillation etc. I have added in hot digested sample 10 ml distilled water and than 40 percent naoh there is so much splashes coming from the flask and than flask was broken. I need to get proper results. Can I follow same way u shown in vedio to get protien in soymilk because I m not getting proper result. May be doing some mistakes somewhere
If you take boric acid with measuring cylinder.. Beleive me you will always get different results in each experiment.. take class a or class b burette for taking boric acid. So many things worng in this experiment
