Analytical, Optical and Biomedical Instrumentation for
Instrumentation Engineering By
www.thegateacademy.com
Syllabus
A.O.B
Syllabus for Analytical, Optical and Biomedical Instrumentation Mass spectrometry. UV, visible and IR spectrometry. X-ray and nuclear radiation measurements. Optical sources and detectors, LED, laser, Photo-diode, photo-resistor and their characteristics. Interferometers, applications in metrology. Basics of fiber optics. Biomedical instruments, EEG, ECG and EMG. Clinical measurements. Ultrasonic transducers and Ultrasonography. Principles of Computer Assisted Tomography.
Analysis of GATE Papers (Analytical, Optical and Biomedical Instrumentation) Year
Percentage of marks
2013
3.0
2012
6.0
2011
2.0
2010
9.0
2009
11.0
2008
16.0
2007
16.0
2006
14.66
2005
12.66
2004
25.0
2003
18.0
Overall Percentage
12.12%
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Contents
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CONTENTS Chapter #1.
#2.
#3.
#4.
#5.
Page No.
U.V, Visible and IR spectrometry
1 - 15
1-3 3-7 7-9 10 - 11 11 - 12 13 13 - 15
Analytical Instrumentation Beer – Lamberts law Infrared Spectroscopy Instrumentation Assigment 1 Assigment 2 Answer Keys Explanations
Mass Spectrometer
16 - 22
16 - 17 17 - 18 19 - 20 21 21 - 22
Introduction Time of Flight Mass Spectrometer Assignment Answer Keys Explanations
X ray and Nuclear Radiation Measurements
23 - 34
23 - 24 24 - 26 26 - 28 29 - 30 30 - 31 32 32 - 34
Origin of X rays X-ray Diffraction – Bragg’s Law Nuclear Detectors Assignment 1 Assignment 2 Answer Keys Explanations
Optical Sources and Detectors
35 - 55
35 - 37 37 - 41 41 - 49 50 - 51 51 - 52 53 53 - 55
Optical Sources LASER Photo Detectors Assignment 1 Assignment 2 Answer Keys Explanations
Interferometer, Applications in Metrology
Introduction Michelson’s Interferometer Working Application in Metrology Assignment
56 – 63 56 56 - 57 57 - 58 59 - 60
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Contents
Answer Keys Explanations
#6. Basics of Fiber Optics
#7.
#8.
#9.
Introduction Construction Fibre Characteristics and Classification Assignment 1 Assignment 2 Answer Keys Explanations
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61 61 - 63
64 – 76 64 64 - 66 66 - 69 70 - 71 71 - 72 73 73 - 76
Ultrasonic Transducers and Ultrasonography
77 - 83
77 77 78 - 79 79 80 - 81 82 82 - 83
Introduction Acoustic Impedence(z) Ultrasonic Transducers Doppler Shift Ultrasound Transducer Assignment Answer Keys Explanations
ECG EEG EMG
84 - 102
84 - 87 87 - 89 89 - 91 91 - 94 95 - 96 97 - 98 99 99 - 102
Sources of Bioelectric Potentials ECG (Electro Cardio Gram) EEG (Electro Encephalogram) EMG (Electromyogram) Assignment 1 Assignment 2 Answer Keys. Explanations.
Clinical Measurement and Computer Assisted Tomography
Introduction Measurement of Blood Pressure Measurement of Blood Volume Measurement of Heart Sounds Test on Blood Cells Principle of Computer Assisted Tomography Assignment Answer Keys Explanations
103 - 114 103 103 - 104 104 105 105 - 109 109 - 110 111 - 112 113 113 - 114
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Contents
A.O.B
Module Test
115 - 126
Test Questions Answer Keys Explanations
115 - 119 120 120 - 126
Reference Books
127
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Chapter 1
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CHAPTER 1 U.V, Visible and IR spectrometry Analytical Instrumentation Analytical instruments are primarily used to obtained qualitative and quantitative information regarding the composition of a given unknown sample. The basic building blocks are: Chemical information source
Analytical instrument
Signal conditioner
Display system
Chemical information source generates signal containing information of the unknown sample. Analytical instruments then generate signal based on the composition of the sample. This stage forms an important building block in analytical instruments where the separation, detection and of the composition is done by employing either emission or absorption or scattering of electromagnetic radiation as the key principle of detection. Electromagnetic Radiation Electromagnetic radiation is a type of energy that is transmitted through space at a speed of 3× m/sec. These radiations do not require a medium of propagation and can also travel through vacuum. Relation between the energy of electromagnetic radiation (normally called as photons) and frequency of its propagation is given by where E: energy h: Planck’s constant
ergs-s (or)
Joules-s
ν: frequency If λ is the wavelength interval between successive maxima and minima of the wave), then C = νλ Where C: velocity of propagation of radiant energy in vacuum. Interaction of radiation with matter S. No Radiation absorbed Energy changes involved 1. Visible, ultraviolet, x – Electronic transitions, vibrational ray rotational changes
or
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Chapter 1 2.
Infrared
3. 4.
Microwave Radio – frequency
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Molecular vibrational changes with superimpose rotational changes Rotational changes They are absorbed by an intense magnetic field.
Spectroscopic methods and corresponding energy states of matter or basis of phenomenon S. No Method Phenomena employed 1. Nuclear magnetic Nuclear spin coupling with an resonance applied magnetic field 2. Microwave spectroscopy Rotation of molecules 3. Infrared and Raman Rotation or vibration of molecules, spectroscopy electronic transitions 4. UV – visible spectroscopy Electronic energy changes, 5. X-ray spectroscopy Diffraction and reflection of X-ray radiation from atomic layers. Electromagnetic Spectrum Fig (1.1) shows the various regions of electromagnetic spectrum which are normally used in spectroscopic works. UV – VISIBLE SPECTROSCOPY 2.5đ?›? M – 2400 Ă…
NUCLEAR MAGNETIC RESONANCE
20 – 100 MHz (~ 300 MHz IN SUPERCONDUCTING INSTRUMENTS) MICROWAVE SPECTROSCOPY 2000 MHz – 300 GHz
Îť
3Ă—
m
3Ă—
m
300 m
10 m
0.67 m
30 m
3 cm
m
7000 Ă…
3000 Ă…
30 Ă… 3Ă—
7000 – 4000 Å
MICROWAVES
FREQUENCY RANGE OF HUMAN EYE
EXTRA HIGH VERY LOW MEDIUM HIGH VERY HIGH ULTRA HIGH SUPER HIGH LOW FREQUENCY INFRARED FREQUENCY FREQUENCY FREQUENCY FREQUENCY FREQUENCY FREQUENCY FREQUENCY
10 kHz
100 kHz
0 – 15 kHz; FREQUENCY RANGE OF AVERAGE HUMAN EAR
1 MHz
30 MHz
450 MHz
NUCLEAR QUADRUPOLE RESONANCE 2 – 1000 MHz
1 GHz
10 GHz
ELECTRON SPIN RESONANCE; X-BAND 9.46 GHz
300 GHz
4.3Ă—
VISIBLE
z
ULTRAVIOLET
z
X-RAY
z
z
INFRARED SPECTROSCOPY 1 MM2.5 đ?›? M 10 – 4000 cm RAMAN SPECTROSCOPY
Fig.1.1 Electromagnetic spectrum from DC to X-ray In the following sections, we discuss the various methods employed (by the analytical instruments) for detection of the composition of the analyte sample in the different regions of the electromagnetic spectrum.
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Chapter 1
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Visible and Ultraviolet: Calorimeter and Spectrophotometer In the visible and ultraviolet region of spectrum, the method of analysis employed by the analytical instruments are based on the absorption of electromagnetic radiation. Calorimeters and spectrophotometers are the analytical instruments used in this region. Principle Whenever a beam of radiant energy strikes the surface of a substance (analyte or sample), the radiation interacts with the atoms or molecules of the substance resulting in absorption (or) transmittance or scattering (reflection) depending on the properties of the sample.
Absorbed Radiation
Transmitted Radiation
Incident Radiation Sample Absorption spectroscopy is based on the principle that the amount of absorption that occurs is dependent on the number of molecules present in the sample. Here the analysis is done by studying the intensity of the radiant power leaving the substance, i.e., the transmitted radiation which is an indication of concentration of the sample. The absorbance is calculated as; Transmittance (T) where: p: energy transmitted P : Incident energy Absorbance
log ( ⁄ ) log
Optical density
( ) log (
⁄ )
Beer – Lamberts Law This law gives a relation between energy absorbed by the sample and the energy transmitted. Absorbance (A) = abc where: a is the absorptivity of the sample (constant) THE GATE ACADEMY PVT.LTD. H.O.: #74, Keshava Krupa (third Floor), 30th Cross, 10th Main, Jayanagar 4th Block, Bangalore-11 : 080-65700750, info@thegateacademy.com © Copyright reserved. Web: www.thegateacademy.com Page 3
Chapter 1
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b is the thickness of the absorbing material c is the concentration of the sample p As we known, A log ( ⁄ ) and T ⁄P ∴ log ( ⁄ )
abc
log ( ) and T =
Assumptions 1. 2. 3.
Here the radiation used is monochromatic (single wave length) in nature. Sample is of low concentration. The others factors that influence the absorption are not considered.
The instrument module for UV and visible spectrometry can be pictorized as below Example: The transmittance of a coloured solution is 0.5, the absorption of the solution is? A = log
= log
)
= 0.3
Example: In a particular sample the absorption is 0.6 for a molar concentration of the solute of 1.0 moles and 2cm path length the molar absorptivity is? A = abc a= Substitute a = 3000 Radiant Source
Wavelength Selector
Solvent
Photo detector
Read out device
Sample
Radiation sources used are 1. 2. 3.
Hydrogen or deuterium discharge lamp(U.V) Incandescent filament lamps 350nm – 2.5µm Tungsten halogen lamps (visible)
Wavelength selection is done with the various dispersive techniques given. Optical Filters Absorption Filter These optical filters usually absorb the radiation and transmit light of single wavelength. There efficiency is poor, when compared to other filters. Interference Filters These filters use interference phenomena. THE GATE ACADEMY PVT.LTD. H.O.: #74, Keshava Krupa (third Floor), 30th Cross, 10th Main, Jayanagar 4th Block, Bangalore-11 : 080-65700750, info@thegateacademy.com © Copyright reserved. Web: www.thegateacademy.com Page 4
Chapter 1
A.O.B
Thus, these filters normally have semi-transparent layers. Light, which is incident on it undergoes multiple reflections between the pair of semi transparent layers and the wavelength that is transmitted through them is determined by the thickness of the dielectric layer. The wavelength selection is done by the relation: mλ d n) sin θ where θ : angle of incidence d : thickness of dielectric spaces, n : refractive index of dielectric spacer. m : order of interference λ : wavelength Monochromators They are the another class of filters, which provide better isolation than optical filters. They are capable or isolating a narrow band of wavelengths effectively. Principle employed for separation of wavelength is done by using a dispersing medium, where the radiant energy gets isolated. Dispersion of radiant energy into different wavelength’s is usually done by prism monochromators or by diffraction grating. Prism Monochromators Here in prism monochromators, the isolation of different wavelengths is done by using the refractive index of wavelengths, which is different for different wavelengths. Thus, radiation of different wavelengths gets disperssed at different angles by prism. Prisms are normally made of glass or quartz. Glass is used in visible region and quartz for ultraviolet region. Resolving Power (R) The term resolving power is applied to spectrum producing devices and means as the ability of the instrument to form separate images of two closely adjacent spectral lines. It is defined generally by the equation where R: resolving power λ : wavelength dλ : smallest wavelength separation, which is separable with the instrument. dλ λ λ and . For prism, the resolving power is given by the expression: t where dμ is the difference or refractive index t : base of the prism. Example: A prism spectrometer uses flint glam prism with glam dispersion 6 0A at λ = 5893 0A find base t of prism?
952cm-1 and dλ =
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