Spectroscopy || Beer- Lambert's Law
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- เผยแพร่เมื่อ 19 ก.ค. 2020
- #biologyanimation #biophysics #spectroscopy #spectrophotometer
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Today we are going to learn about the spectroscopy and beer lambert’s law.
What is spectroscopy?
It is the study of the interaction between electromagnetic radiation and matter.
This matter can be any atoms, molecules or ions.
The electromagnetic spectrum ranges from very short wavelengths like gamma rays to long wavelengths such as radio waves.
The visible range is approx. 400-700 nanometer.
Now, coming to the types of spectroscopy.
When electromagnetic radiation meets the matter, the matter may absorb emit or scatter the radiation.
Depend on which there are three types of spectroscopy-absorption, emission and scattering.
Today we will talk about only absorption spectroscopy.
The basic principle of absorption spectroscopy is when a beam of monochromatic light passes through a solution or matter, some of its radiation may be absorbed.
This absorbance is measured with the help of an instrument known as a spectrophotometer.
Beer-Lambert’s law is based on two different laws.
The lambert’s law states that, when a monochromatic light passes through a transparent medium, the intensity of transmitted light decreases exponentially as the thickness of absorbing material increases.
Beer’s law states that the intensity of transmitted monochromatic light decreases exponentially as the concentration of the absorbing substance increases.
This Beer-Lambert’s law can be expressed mathematically by the formula
A=log I_o/I=εcl
Where A refers to the absorbance, I_o & I is the intensity of incident & transmitted light, respectively.
ε is the excitation coefficient which is constant for a particular matter.
C is the concentration of the sample & l is the path length.
T refers to the transmittance which is expressed by the ratio of I and I_o.
If we derive the relationship of absorbance with the percent transmittance from the above formula, we get absorbance is equal to 2-〖log〗_10%T
So, in spectrophotometer, you can get both the reading of absorbance & transmittance.
Now, see if we increase the sample concentration, the absorbance increases while the transmittance decreases.
However, if we change the path length, the absorbance increases and the transmittance decreases further.
Now, coming to the applications of the spectrophotometer, for example, we are taking protein estimation.
Let you have a sample of unknown protein concentration with you and you want to estimate it’s concentration.
First, you have to take a series of known concentrations of protein along with a blank.
Now you will add reagents to all the tubes.
The protein will give color after reacting with reagents.
The color intensity is directly proportional to the protein concentrations.
Now you have to measure the absorbance for each known concentration of the proteins along with your sample.
When you plot those readings in a graph, it will give you a standard curve.
From the standard curve, the value of 1 absorbance is calculated.
Now using the formula, you can calculate the protein concentration of the unknown sample.
Apart from protein estimation, spectroscopy is used to measure DNA/RNA concentration in enzymatic assays, in ELISA or measuring any concentrations of molecules which give any color of the UV-Visible range when in a solution.
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Thanks. I wish our PhD teachers in the university had only one tenth of your teaching talent
Thank you very much, please share among friends if you found it helpful.
Oh my God this video is so informative thanks I wish you could do more on spectroscopic methods please
you just grabbed my strong attention...awesome
Very informative video ❤ it helps me a lot. Thank you ma'am😊.
Wonderfully explained...Quiet thankful for your help and answering the questions arising in my mind..
Glad it was helpful!
Thank you very much, I'm french I revise this chapter intituled : "Beer Lambert Law" or in French : "La loi de Beer Lambert" and in order to develop in English level and enhance it, I would to look this video. It is very good explicated ! Thank you !
merci beaucoup pour votre geste d'amour. Je souhaite tout le meilleur, continuez à nous soutenir.
@@RethinkBiology merci j'ai pu enrichir en plus de ça plus de vocabulaire en anglais
Mam its so nice explanation 😊 it help me a lot❤
Many many thanks for your nice and effective presentation!!!!!
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Thank you mam its helps!
Thank you so much 🙏🏼🙏🏼
Thankyou teacher thanks alot for this great explanation I was fed up of my teacher's teaching
But I love it and for the first time I'm feeling confident that now I can explain and wite it
Please make more and more videos
UV spectrophotometer
IR spectrophotometer
Fluorimetry and colorimetry and many more topics please
I have likes and shared to all my classmates and also subscribed
Thankyou sooo much teacher
Thanks alot
Thank you very much.. keep loving and supporting us... Will definitely try to bring videos on those topics... ❤️
Thank you Mam. Khub sundor explaination. Many many thanks.
Thanks a lot dear, please do share if you liked our video
Very well explained mam ,
Really outstanding explanation
Thank you very much
Thank you!
Very good video...... thank you...
Thank you too
So helpful!!
Thanks a lot 🙏🏻🙏🏻
Thank you ☺️
Epsilon is the extinction coefficient..
(Not excitation ) 😁🙏🏻
Most underrated biology channel
You are doing a great job mam😇😍
Thank you very much. Be with us. 😊
Thank you 😊
Best video
Thanks a lot dear
Thank you
Thanks ❤
Thank u mam
Nice explanation
Thanks
Your voice is very nice mam
Tnq ma'am
thank u so much ........
Most welcome
Thnxx mam
Welcome.. keep supporting us..😊
Plsss upload many videos in gpat and government exam point of view plssss
Of course, please suggest us some topics which you found difficult to understand.
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mam , can i get the video ??
Blanks main pehly sy kya hota hain then we drop protein
Blank means solution without protein, baki sab me proteins ki different concentrations honge, lekin blank me nhi, then we drop the reagent which gives colour on reacting with proteins in the samples.
Umesh chaudhari CBZ
Take a breath and study
ma'am, I like ur content very much, but the background music is very annoying, we only want to hear ur voice.. if it possible thnq ma'am
Thank you so much for your feedback,will keep that in mind..😊
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Doubt to clear madam,
Spectrophotometer Works under Lambert's Law or Beer's Law - what is difference between them..
A spectrophotometer can work under both Beer's law and Lambert's law, as these laws describe different aspects of light absorption in a solution.
Beer's law states that the absorbance of a solution is directly proportional to the concentration of the absorbing substance in the solution, as long as the path length of the light through the solution is constant. This law is often used to measure the concentration of a solute in a solution by measuring the absorbance of light at a specific wavelength.
Lambert's law, on the other hand, states that the absorbance of a solution is proportional to the path length of the light through the solution, as well as the concentration of the absorbing substance. This law is used to calculate the amount of light absorbed by a solution with a known concentration and path length.
In practice, spectrophotometers often use both laws in combination to accurately measure the concentration of a solute in a solution. The spectrophotometer measures the intensity of light passing through the solution at a particular wavelength, and then uses Beer's law to calculate the concentration of the solute in the solution. The path length of the light through the solution is also taken into account using Lambert's law to ensure accurate measurements.
Hope this cleared your doubt
what is that about excitation coefficient? can u explain that part pls?
The excitation coefficient is another name for the molar extinction coefficient, which is a measure of how strongly a chemical species absorbs light at a given wavelength. It depends on the molecular structure and environment of the species, as well as the frequency of the light.
The excitation coefficient can be experimentally determined by measuring the absorbance of a series of solutions with known concentrations and path lengths, and then plotting absorbance versus concentration. The slope of the linear regression line is equal to the excitation coefficient times the path length. Alternatively, if the excitation coefficient is known, the concentration of an unknown solution can be calculated from its absorbance and path length using the Beer-Lambert law.
I hope this helps you understand the concept of excitation coefficient in Beer-Lambert law. 😊
شرح حلو جدا
لكن بالعربي بيكون افضل علشان نفهم اكثر
ترجمة النص باللغة العربية إذا استطعت. يمكنني تزويدك بنص الفيديو. سيكون مفيدًا للعديد من الأشخاص مثلك.
Background noise should be removed.
those signs that says "subscribe" are so annoying, distracting. It kept showing up
Not much depth..
Will try to put a much depth version very soon
Super explanation, but i felt like your voice is very over acting