Spectrometer / Spectrophotometer
- an instrument/ device used to measure the absorbance of light that resolve polychromatic radiation into different wavelength.

A Spectrophotometer can be separated into 5 parts:
(1) Light source
(2) Monochromator
(3) Sample Cell
(4) Detector
(5) Readout device
 
When the source light reaches the diffraction grating, only one light will pass through the exit slits and interact with the sample. The light that passes through the sample is the transmittance and will be measured by the detector.
 
In this case, we can also use the formula of A = -logT = log (Po/P) to calculate the percentage transmittance or absorbance.

This video below explain clearly how a spectrophotometer works. Enjoy watching!
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How does spectrophotometer work?

The next video is about sample preparation for Fourier Transformed Infrared (FTIR) machine. This video shows detailed steps on preparing the sample pellet step-by-step in the lab.
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FTIR Spectroscopy (prepare Solid Sample using Hydraulic Press)
Measurement of Absorbance & Transmittance
Single-beam spectrophotometer vs Double-beam spectrophotometer
 

 
Below shows some of the comparisons between two types of spectrophotometer.
 

 
The information above allows me to understand the differences between the two devices better.

The video below explains to us how a UV-Visible Spectrophotometer looks like and the way to use it.
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Double-beam UV-Vis Spectroscopy

Reflection 

Today’s class is short and easy to understand with the extra video sources provided by AP Dr. Bawadi.
I learned about the 5 main parts of a spectrophotometer, namely: source, monochromator, sample, detector, and readout device. The videos shared by our lecturer helps me to understand the mechanism of spectrophotometer better. I finally learned to prepare the sample pellet in the right way through the detailed video. Other than that, I learned about the differences between the single-beam and double-beam spectrophotometer.

I have seen a single-beam and a double-beam spectrophotometer in the lab back then but I do not know about the differences and the working mechanism behind them. Now, I am able to understand the device through this chapter.

There is no tutorial session this week and we will be having our Test 1 on 3/7/2020 (Friday) which will be covering Chapter 1 to Chapter 4.

To know more about me
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