Instrumentation Flashcards
Atomic Absorption Spectrophotometer
used to measure concentration by detecting the absorption of electromagnetic radiation by atoms rather than molecules
Hollow-cathode lamp
usual LIGHT SOURCE in AAS
Anode, Cylindrical cathode, inert gas (helium and argon)
the hollow-cathode lamp consists of an evacuated gas-tight chamber containing
Electrodeless discharge lamp
relatively new light source for AAS
Radiofrequency generato
supplies the energy to excite the element, causing a characteristic emission spectrum of the element
Premix long-path burner
most common burner
proportional
the amount of light absorbed is ________ to the concentration
monochromator
- used to isolate the desired emission line from other lamp emission lines.
- serves to protect the photodetector from excessive light emanating from flame emissions
PM Tube
usual LIGHT DETECTOR
Flameless atomic absorption
requires an instrument modification that uses an electric furnace to break chemical bonds
Zeeman effect
presence of an intense static magnetic field will cause the wavelength of the emitted radiation to split into several components
Atomic Absorption Spectrophotometry
- sensitive and precise
- routinely used to measure concentration of trace metals that are not easily excited
10^-5 seconds
excited state lasts about how many seconds before the electron loses energy and returns to the ground state
stokes shift
the difference between the maximum wavelengths, excitation, and emitted fluorescence
Filter fluorometers
measure the concentration of solutions that contain fluorescing molecules
