Analytical Methods Flashcards
Spectrometry
Spectrophotometry, AAS, MS
Luminescence
Fluorescence & Chemiluminescence
Electromagnetic methods
Electrophoresis, Potentiometry & Amperometry
Chromatography
Gas, Liquid, Thin-layer
Photons of energy traveling in waves
Electromagnetic radiation
E = hv
Planck’s formula
Transmitted via electromagnetic waves that are characterized by their frequency & wavelength
Energy
Distance between 2 successive peaks
Wavelength
Number of vibrations of wave motion per second
Frequency
400-700nm
Visible spectrum
<400nm
UV
> 700nm
IR
Most common light source in visible & near-IF
Incandescent tungsten/tungsten-iodide lamp
Light source used for UV
Deuterium & mercury arc
Type of monochromator: A wide band of radiant energy & have decreased transmittance of the selected wavelength
Colored glass filter
Type of monochromator: Principle of constructive interference of waves
Interference filters
Type of monochromator: Narrow beam of light focused on a prism is refracted as it enters the denser glass
Simple glass prism
Type of monochromator: Most commonly used; wavelengths bend as they pass a sharp corner
Diffraction gratings
The presence of an intense static magnetic field will cause the wavelength of the emitted radiation to split into several components
Zeeman effect
It is checked by didymium filter or cobalt chloride or potassium dichromate
Wavelength accuracy
It is checked with quartz mercury arc lamp/transmission standards
UV spectro
It’s checked by running different concentration of the same solution
Photometric linearity
It’s checked with Nickel sulfate at 510nm
Photometric accuracy
It detects baseline drift
Baseline stability
Difference between the maximum wavelengths, excitation & emitted fluorescence
Stokes shift
The total range of wavelengths transmitted
Bandpass
The most commonly used photodetector
Photomultiplier tube (PMT)
Measures light at a multitude of wavelengths - detect less amount of light
Photodiode
Corrects absorbance caused by the color of the reagents
Reagent blank
Measures absorbance of the sample & reagent in the absence of the end product
Sample blank
It measures light emitted by a single atom burned in a flame
Flame Emission Photometry (FEP)