INSTRUMENTATION Flashcards
Filter Photometry is also called as? [2]
Emission Flame Photometry
Flame Emission Spectrophotometry
The measurement of emitted light when an electron in an atom becomes excited by heat energy produced by the
flame.
Emission Flame Photometry /Flame Emission Spectrophotometry/ Filter Photometry
FES is used primarily to determine concentration of [3] since these alkali metals are easy to excite.
K+
Na
Lithium
Filter Photometry:
_________ is used to excite the electrons present in atoms → excited electrons release/emit light →__________ is being measured
Once the atom is exhausted, losing the light emitted → go back to ________
Flame
light energy
ground state
Components of the Flame Photometer
[4]
Gases
Atomizer or Burner
Monochromators
Detector
Excited atoms return to ground state by emitting light energy that is characteristic of that atomic species.
FES
FES
________ using a mixture of hydrogen and oxygen gas [3 examples]
Gases
acetylene
propane
natural gas
FES:
Source or fuel of this machine producing the flame
Gases
FES:
breaks up the solution into finer droplets so that the atom will absorb heat energy from the flame and get excited.
Atomizer or Burner
FES:
Sprays onto fuel and covert it to finer droplets
Atomizer
FES Types of Burners
Total Consumption Burner
Premix Burner
aspirate sample directly into the flame, the gases are passed at high velocity over the end of the capillary suspended in the solution.
Total Consumption Burner
involves the gravitational feeding of solution through a restricting capillary into an area of high velocity gas flow where small droplets are produced and passed into the flame.
Premix burner
Total Consumption Burner or Premix Burner
Fuel is aspirated through capillary action (pulled upwards)
Total Consumption Burner
Total Consumption Burner or Premix Burner
Source of fuel comes from upper part of system
Premix Burner
FES Monochromators [3]
Na filter
K filter
Lithium
Na filter: transmit [color] light [#nm]
K filter: transmit [color] light [#nm]
Lithium: transmit [color] light [#nm]
yellow
violet
red
589
767
761
Filter Photometry Detector [1]
Photocell
referred to as the internal standard, also acts as a radiation buffer in Filter photometry
Lithium
Reasons why lithium is preferred in EFP?
Emission characteristics are similar to Na and K
Normally present as trace element in the human tissue + does not present interferences in the determination.
Its purpose is to achieve stability where there are fluctuations caused by
changes in fuel of air pressure which affects flame temperature and rate of sample aspiration.
Lithium
CRITERIA IN CHOOSING THE INTERNAL STANDARD/Lithium for EFP
➢ Its concentration must be precisely the ______ in all samples and standards.
➢ Energy required of the internal standard must be close to that required to ______ the element being measured.
➢ Must be [normally/not normally] found in ion being analyzed.
✓ In cases where lithium is the analyte ,_______ is used as internal standard
same
excite
not normally
cesium
Based on absorption of electromagnetic radiation by the atom
AAS
____________
The element is not excited but they are dissociated from their chemical bonds and placed in the __________________. Breaking chemical bonds
AAS
unionized, unexcited ground state
[MORE SPECIFIC] AAS:
sample + ______ = aspirated sample –> combined with [Radiaton source] –> Radiation source is modulated by________ –> [Wavelength selector] –> [Detector] –> _________ –> Signal processor
Burner
Hollow Cathode lamp
Mechanical Rotating Chopper
Monochromator- Prism/Diffraction gratings
Photomultiplier tubes
AAS:
sample + ______ = aspirated sample –> combined with ________ –> wavelength selector –> ________ –> _________ –> Signal processor
Atomizer
Detector
Amplifier
AAS components [6]
Light Source
Mechanical Rotating Chopper
Meter/Read-out device
Burner
Monochromator
Detector
AAS light source
Hollow cathode lamp
AAS
produces a wavelength of light, specific for the kind of metal in the cathode. Gives specific wavelength of light
Hollow cathode lamp
modulates/regulates light beam coming from the hollow cathode lamp. Controls amount of light that will go into the next component of the machine
Mechanical Rotating Chopper
uses flame to dissociate the chemical bonds and form free, unexcited state of atoms in AAS
Burner
A type of burner in AAS, flame is more concentrated and can be made hotter, thus lessening chemical interferences.
Total consumption burner
A type of burner in AAS, gases are mixed and the sample is atomized before entering the flame and the large droplets go to waste and not in the flame.
Premix burner
A type of burner in AAS, produces large droplets in the flame and produces a high acoustical noise.
Total consumption burner
A type of burner in AAS, where it has less noisy signals with longer pathlength and greater absorption and sensitivity.
Premix burner
A type of burner in AAS, where flame is less hot and therefore cannot dissociate metal complexes.
Premix burner
selects the desired wavelength from a spectrum of wavelength which could either be a [2]
Monochromator
prism
diffraction gratings
AAS DETECTOR – uses __________ to measure the intensity of the light signal.
Photomultiplier tubes
where results are displayed in AAS
Meter/Read-Out device
Interferences in AAS
[3]
Ionization
Matrix
Lanthanum or Strontium chloride
situation at which atoms in the flame become excited and emit energy instead of staying in the ground state.
Ionization
formation of solids from sample droplets due to enhancement of light absorption by organic solvents
Matrix
interefence in AAS which forms stable complexes with phosphate→to avoid calcium interference
Lanthanum/Strontium chloride
____________
The unknown sample is made to react with a known solution [________] in the presence of an indicator.
Volumetric/Titrimetry/Titration Method
Volumetric method is also called as? [2]
Titrimetry
Titration Method
Examples of Titration Methods [2 + their examples]
Chloride determination
– Schales and Schales
Calcium determination
– EDTA Titration
where indicator reacts to the acid
Point of equivalence
solution of the pure form of the sample and its derivatives + the determination of its dry weight.
Gravimetric
Example of Gravimetric
Total Lipid determination
Allow solutions to evaporate and wait for the analytes to form →measure the dry weight
Gravimetric
Determines the amount of light emitted by a molecule after excitation by electromagnetic radiation analytes will fluoresce/lit up esp. in dark background
Fluorometry
Measures the amount of light intensity (produced by analyte) present over a zero background
Fluorometry
Fluorometry light source
Mercury Arc
Xenon lamp