Analytical Methods Flashcards
Energy are electromagnetic waves that are characterized by ___________ and ___________.
Frequency and Wavelength
Wavelength
HORIZONTAL (width) distance from each wave
Amplitude
VERTICAL (height) distance from each wave
Frequency
Number of waves/vibrations
Wavelength is ___________ proportional to Frequency and Energy
Inversely proportional
Frequency is _________ proportional to Energy
Directly Proportional
Wavelengths are expressed in _________.
Nanometer
Increased Color Reaction: ________________
Increased analyte concentration
Colorimetric Methods
Spectrophotometry
Flame Emission Photometry
Atomic absorption Spectrophotometry
Principle in Spectrophotometry
Measurement of the LIGHT TRANSMITTED in the solution to determine the concentration of the LIGHT ABSORBED in the solution
______________ is used to verify WAVELENGTH ACCURACY and for instruments with narrower bandpass.
Mercury Vapor Lamp
Light Source
a.k.a Radiant energy source/Lamps
Provide limited radiation and polychromatic light
Most common light source for VISIBLE-INFRARED light
Tungesten
Routinely used for UV light
Deuterium
Enumerate: Light Source (UV Light)
Mnemonics: MXHD
Mercury Arc
Xenon
Hydrogen Lamp
Deuterium
Enumerate: Light Source (Infrared Light)
Mnemonics: MG
Merst Glower
Globar
Number of Photodetectors in Double Beam in SPACE
2 photodetectors
Number of Photodetectors in Double Beam in TIME
1 photodetector
SIMPLEST type of absorption spectrophotometry
Single Beam spectrophotometry
Single Beam Spectrophotometry
One measurement at a time
Double Beam Spectrophotometry
Splits monochromator light into 2 components
Emits radiation that CHANGES INTENSITY
Continuum Source
Emits limited radiation in discrete lines
Line Source
Monochromator
“Wavelength Selector” - Isolate specific or individual light
Most common and Best utilized monochromator
Diffraction Gratings
Synonyms of “Cuvette”
Sample Holder
Absorption Cell
Analytical Cell
Sample Cell
Cuvette
Holds the solution which concentration is to be measured
Most Common sample holder
Aluminum Silica Glass
Sample holder BEST utilized for UV
Quartz
Photodetector
Detect and Convert transmitted ight into PHOTOELECTRIC ENERGY
Most common Photodetector
Photomultiplier Tube (PMT)
Excellent in LINEARITY
Photodiode
Routine path length of of Cuvettes
1 cm
Range of Aluminum Silica Glass cuvettes to transmit light effectively
> 220 nm
What to do when results are NON-LINEAR?
- Blank Technique
- Reagent Blank
- Sample Blank
Most common cause of loss of Linearity
Stray Lights
Principle in Flame Emission Spectrophotometry (FEP)
Light Emitted from EXCITATION of electrons from lower to higher energy source.
Flame Emission Photometry measures light emitted by a ___________ burned in a ________.
Single atom
Flame
FEP.
Light Source: ___________
Photodetector: _______
Light Source: Flame
Photodetector: Photocell
Indirect Internal standard Method (Recalls: March, 2019)
Sodium: ________
Potassium: _________
Calcium: __________
Lithium: __________
Sodium: Yellow
Potassium: Purple
Calcium: Orange
Lithium: Red
Quality Assurance in FEP. Flickering Lights indicates changes in the ____________ of the instrument.
Fuel reading
Preferred Internal Standard Method (FEP)
Lithium
Cesium
Principle: Atomic Absorption Spectrophotometry
Elements are not excited by merely dissociating from its chemical bond and are placed in an unexcited, unionized, ground state.
Atomic Absorption Spectrophotometry (AAS)
Light Source: ________
Photodetector: _________
Light Source: Hallow Cathode Lamp
Photodetector: PMT
Reference method for CALCIUM, MAGNESIUM, TRACE METALS.
Atomic Absorption Spectrophotometry
Principle: Volumetry/Titrimetry
Unknown sample is made to react with Known sample in the presence of INDICATOR
Methods using Volumetry
Schales and Schales: Chloride
EDTA Titration Method: Calcium
Principle: Turbidimetry
Measures the amount of light BLOCKED in a turbid solution.
Turbidimetry measures abundant _________ like proteins and bacteria.
Large Particles
Principle: Nephelometry
Measures the amount of Light SCATTERED in a turbid solution.