PRELIM 1: ANALYTICAL TECHNIQUES AND INSTRUMENTATION Flashcards
is the highest point
Crest or peak
is the lowest
point
trough
is the number of waves that pass an observation
point in a unit of time
Frequency
is the distance of two peaks/crest or troughs
when light travels in a wavelike manner
Wavelength
is the distance between two adjacent peak and
trough
Amplitude
is inversely proportional to the frequency of
the light wave
Wavelength
is inversely proportional to the wavelength of light
Energy
Wavelength or frequency of the electromagnetic waves are perceived as
color or hue
Height or amplitude of the electromagnetic waves are
perceived as
intensity or brightness
There are two kinds of wavelengths: ______which
can be observed at 340-700nm and the_____
which could either be Ultraviolet with a wavelength of less
than 400nm or Infrared with a wavelength of greater than
700 nm.
Visible Spectra, Invisible Spectra
Principle: Measures the amount of light transmitted to determine the concentration of the light-absorbing substance in the solution; the measurement of the light transmitted by a
solution to determine the concentration of the light-absorbing
substance in the solution
Spectrophotometry
states that the concentration of
substance is directly proportional to the amount of light absorbed but inversely proportional to the logarithm of transmitted light
Beer-Lamberts Law
= amount of light
absorbed
Absorbance (OD-optical density)
-provides electromagnetic radiation as visible,
infrared, or UV light
Light source
type of light source can emit UV light
Mercury Vapor Lamp
type of light source ideal for emission
of light within the visible region (iodide prolongs stability of Tungsten); produces energy wavelength from 340-700nm (visible region); used for moderately
diluted solution
Tungsten/Tungsten-iodide lamp
type of light source energy wavelength UV
range (down to 165nm)
Deuterium Discharge Lamp
Types of light source
-Tungsten/Tungsten-iodide lamp
-Mercury Vapor Lamp
-Deuterium Discharge Lamp
-Infrared Energy Source
-Quart Halide Lamp
-Mercury vapor Lamp
-hallow cathode lamp
type of light source above 800 nm
Infrared Energy Source
- reduces stray light and prevents scattered light from entering the monochromator
Entrance Slit
type of light source contains small amt of halogen such as iodine to prevent the decomposition of vaporized tungsten
Quart Halide Lamp
type of light source exists narrow bands of energy at well defined places in the spectrum UV and visible light
Mercury Vapor Lamp
Spectophotometer components
-light source
-entrance slit
-monochromator
-exit slit
-analytical cell
-detector
-meter
type of light source consists of a gas-tight
chamber containing anode, a cylindrical cathode and
insert gas such as helium
Hollow Cathode Lamp