Could dilution of sample cause negative absorbance? I think I diluted the samples I was measuring, but not my blank (which contained a buffer solution). If so, how should I adjust for that negative absorbance value...
Help with a question ????? A compound absorb light in 227 nm. The standard curve calibration for the compound is Abs = 372x + 0,6432 which the concentration is g/100mL. The technique was analytical standard adding from fluoxetine hydrochloride (C17H18F3NO.HCl - molar mass = 345,79 g/mol). So determine the concentration in mol/L from the analysed solution. Show all calcs progression.
@@dobergeron yes. and i jumped it. Full quesion: Standard addition is an analytical technique of extreme importance to an analyst, as it eliminates the interfering effect in most determinations. Fluoxetine is widely used as fluoxetine hydrochloride, also known as Prozac®. This is indicated in the treatment of depression, associated or not with anxiety. This compound absorbs ultraviolet light at a wavelength of 227 nm. It has in its structure a stereocenter, being a chiral drug. It is known that only the (R) -fluoxetine isomer has activity, while the other enantiomer has no pharmacological action and there is no evidence of toxicity to the organism. In an industry, when performing the Fluoxetine analysis, the following analytical calibration curve was obtained, in which the concentration is in g / 100 mL: Abs = 372 CFluoxetine + 0.6432. Knowing the analysis was performed according to the standard addition technique and that the molar mass of fluoxetine hydrochloride (C17H18F3NO.HCl) is 345.79 g / mol. Determine the mol / L concentration in the analyzed solution.
@@dobergeron I thinks i need to use this equations but i dont know how. S=k.Ca y = m*x + b Y = S x = Vs m = k . Cs / Vt b = k.Cx.Vx / Vt It's a friend whom sent me and i couldn't to do it. I researched i found this 3B4 equation. ( www.mathcentre.ac.uk/resources/uploaded/3b4printableversion.pdf ). But i dont know the source from y value which has been used. I have the alternatives but idk which is the correct: 2,25x10-5 mol/L 5,58x10-5 mol/L 5,0x10-5 mol/L 9,69x10-5 mol/L 3,08x10-5 mol/L
As a professor myself, I don't think I should comment on your question. I'm sorry, ask your prof... I'm really sorry but I can't give you the answer. There are a lot of resources available, you can do this. Isolate each variable and look how to solve. Hint: look at extinction coefficient... ;)
IF we have real samples in a complex matrix, such as sediments. And the analyte is in very low concentration. Could you explain the procedure, when to use blanks, how to prepare the calibration curve, if we fortify the samples because the concentration is too low, or if there are more reasons to do it, how to check matrix effect, and if something else needs to be done with standards and blank? In this case, we would want to analyze using HPLC-UV detector. Thanks!
Thank you for your question. Unfortunately, I will have to let you know that your question involves a much higher level of experience and knowledge and even attempting to answer your question might lead you in the wrong direction. I certainly do not want you to waste your valuable samples due to a mistake I might do. There must be published methods and/or procedures or other experts that would answer this very specific question much better than me. Good luck!
does adsorption of chitosan absorb at any wavelength compared to non adsorbed? (I assume the aDsorption word is not a typo, very different from aBsorption...
@@DominicBergeronPhD sir, when we plot graph between absorbance and concentration then what's the effect of dilution I mean if absorbent is dilute then more absorbenc yes or not ? nd how will we form a standard solution....?
@@almaanmani7361 a .more diluted solution will give you lower absorbance values, that's Beer's law. I'm not sure with chitosan, I never worked with it, but in order to make a calibration curve you will need to make several solutions of chitosan and read the corresponding absorbance at a specific wavelength. Make sure you cover a wide range of concentrations and be aware of the limitations of your instrument
Sir I have coated one polymer on one of the metal oxide nanoparticles.after completion of coating process,i washed it with water to remove uncoated polymers.Now i have to know how much polymer is coated or how much left out?Is it possible to find out this using UV Vis spectroscopy techniques,please reply sir
Thank you from Cameroon 🇨🇲🙏
Could dilution of sample cause negative absorbance? I think I diluted the samples I was measuring, but not my blank (which contained a buffer solution). If so, how should I adjust for that negative absorbance value...
Thanks sir ...now I clarified what went wrong...❤
Help with a question ????? A compound absorb light in 227 nm. The standard curve calibration for the compound is Abs = 372x + 0,6432 which the concentration is g/100mL. The technique was analytical standard adding from fluoxetine hydrochloride (C17H18F3NO.HCl - molar mass = 345,79 g/mol). So determine the concentration in mol/L from the analysed solution. Show all calcs progression.
Looks like this is an exam question... is it? :)
@@dobergeron yes. and i jumped it. Full quesion: Standard addition is an analytical technique of extreme importance to an analyst, as it eliminates the interfering effect in most determinations. Fluoxetine is widely used as fluoxetine hydrochloride, also known as Prozac®. This is indicated in the treatment of depression, associated or not with anxiety. This compound absorbs ultraviolet light at a wavelength of 227 nm. It has in its structure a stereocenter, being a chiral drug. It is known that only the (R) -fluoxetine isomer has activity, while the other enantiomer has no pharmacological action and there is no evidence of toxicity to the organism.
In an industry, when performing the Fluoxetine analysis, the following analytical calibration curve was obtained, in which the concentration is in g / 100 mL: Abs = 372 CFluoxetine + 0.6432.
Knowing the analysis was performed according to the standard addition technique and that the molar mass of fluoxetine hydrochloride (C17H18F3NO.HCl) is 345.79 g / mol. Determine the mol / L concentration in the analyzed solution.
@@dobergeron I thinks i need to use this equations but i dont know how.
S=k.Ca
y = m*x + b
Y = S
x = Vs
m = k . Cs / Vt
b = k.Cx.Vx / Vt
It's a friend whom sent me and i couldn't to do it. I researched i found this 3B4 equation. ( www.mathcentre.ac.uk/resources/uploaded/3b4printableversion.pdf ). But i dont know the source from y value which has been used.
I have the alternatives but idk which is the correct:
2,25x10-5 mol/L
5,58x10-5 mol/L
5,0x10-5 mol/L
9,69x10-5 mol/L
3,08x10-5 mol/L
As a professor myself, I don't think I should comment on your question. I'm sorry, ask your prof... I'm really sorry but I can't give you the answer. There are a lot of resources available, you can do this. Isolate each variable and look how to solve. Hint: look at extinction coefficient... ;)
please , could you make a video continuing with calibration curves, going further in advanced level?
What would you like to see...what would be useful to you?
IF we have real samples in a complex matrix, such as sediments. And the analyte is in very low concentration. Could you explain the procedure, when to use blanks, how to prepare the calibration curve, if we fortify the samples because the concentration is too low, or if there are more reasons to do it, how to check matrix effect, and if something else needs to be done with standards and blank? In this case, we would want to analyze using HPLC-UV detector. Thanks!
Thank you for your question. Unfortunately, I will have to let you know that your question involves a much higher level of experience and knowledge and even attempting to answer your question might lead you in the wrong direction. I certainly do not want you to waste your valuable samples due to a mistake I might do. There must be published methods and/or procedures or other experts that would answer this very specific question much better than me. Good luck!
Sir, how we plot graph for adsorption of chitosan..?
does adsorption of chitosan absorb at any wavelength compared to non adsorbed? (I assume the aDsorption word is not a typo, very different from aBsorption...
@@DominicBergeronPhD please guide in this regard...
@@almaanmani7361 you need to be more specific. Sorry, I'm not sure I understand what your question is. Really sorry....
@@DominicBergeronPhD sir, when we plot graph between absorbance and concentration then what's the effect of dilution I mean if absorbent is dilute then more absorbenc yes or not ? nd how will we form a standard solution....?
@@almaanmani7361 a .more diluted solution will give you lower absorbance values, that's Beer's law. I'm not sure with chitosan, I never worked with it, but in order to make a calibration curve you will need to make several solutions of chitosan and read the corresponding absorbance at a specific wavelength. Make sure you cover a wide range of concentrations and be aware of the limitations of your instrument
on dilution isn't concentration is decreased than original one
Sorry....I don't know what you mean
Sir
I have coated one polymer on one of the metal oxide nanoparticles.after completion of coating process,i washed it with water to remove uncoated polymers.Now i have to know how much polymer is coated or how much left out?Is it possible to find out this using UV Vis spectroscopy techniques,please reply sir
what is weighting factor
Thank you very much