best video on the internet by a long way. its just the slope divided by the intercept yo. forget the massive equations

this video is very informative and helpful.... it deserves some more likes

Thankyou for this video. It helped my in working out a BHT stabilizer content in a sample by HPLC. I've not tried standard addition before as an approach, always having worked with validated methods. For me it has demonstrated that comparing a classical external standard approach and this approach that I end up with very agreeable values - which gives me confidence I have no co-eluting signal in my sample matrix with the BHT. Blank injections showed the BHT region was clear but this has given me additional confidence with my HPLC method and component separation.

@sunilparanjape416

2 жыл бұрын

CG ch ch c HC vvv

@sunilparanjape416

2 жыл бұрын

By

If you have adequate sensitivity, it is better to dilute and shoot with an external calibration curve so that sample responses come up near the middle of your curve. Methods should evaluate matrix interference early in development.

So you need to add the calculated initial concentration of 6,4 mM to the x values to get the real concentration of your standards? And do the same to determine the concentration of lets say, a QC or patient sample?

Robert LeSuer, thank you very much for such a nice explanation. However, I am struggling to understand the calculation of "x error" calculation, which I am sure is due to my poor understanding skills. I using the same equation you were modelling to calculate the "x error". But I am getting the error message, which, I am suspecting could be due to typo error. I am pasting the equation I am using, please guide me where I am making mistake. =F13/ABS(E11)*SQRT(1/5+AVERAGE(G5:G9)^2/(E11^2*SUM((F5:F9-AVERAGE(F5:F9))^2))). Could you please share the right equation that it will help me to come out of miserable situation.

@bobthechemist

8 жыл бұрын

+waqar jadoon I'm assuming you are getting the #VALUE error. The function is an array function, and you must tell Excel that. To do so, left click on the cell, press F2, then evaluate it using CTRL-SHIFT-ENTER. You should get a number at this point. Hope that helps.

Dear Robert, why we need to adjust the signal of the instrument as the signal is already increase by the signal of standard addition and sample itself, Regards,PK

@IngAndrej

3 жыл бұрын

Hi Paramee, I also think, that this is not correct. I think Robert should calculate concentration of standard added to sample like this x=$B$5*(D5/(D5+$B$4)) and that the signal should stay the same as it was measured. Than the answer is slightly different [x]=6,532

hi. nice presentation. is this excel spreadsheet available for download? thanks

@bobthechemist

8 жыл бұрын

+vacakpocok Unfortunately, I can no longer find the original excel file used in this video. I borrowed very heavily from Harris' Quantitative Chemical Analysis textbook, and if you can find a copy, you will find that the author provides good instructions on how to create the spreadsheet in Chapter 5.

For my brain capacity it was very complicated explanation 🥺. Getting calibration curve and using straight fit equation is pretty simple 🤷‍♀️

@bobthechemist

3 жыл бұрын

I have complete faith that your brain capacity can handle it!!!! Keep up the work.

You don’t even have to calculate all those values to find your original concentration you can just create a linear line in excel by adding chart element and add a equation and it’ll give you m and b you just set y equal to zero and solve

7k views and only 11 likes? c'mon now guys, toss a like out if the video helped you.

can i get an Excel sheet model of this session?

@bobthechemist

Жыл бұрын

I'll look; however, the video is from 2014 and I don't think I have that spreadsheet any longer. Sorry.

Chem 140 people? here lol