Instrumentations Flashcards
pH Meter
It measures the hydrogen ion concentration of a given solution.
Two electrodes equipped in a pH meter
Glass electrode and Reference electrode
Glass Electrode
It consists of a thin, pH-sensitive glass membrane that consists of a solution with constant concentration of hydrogen ions.
Reference Electrode
It incorporates a salt bridge that is filled with a saturated potassium chloride solution.
Spectrophotometry
A method used to measure how much a chemical substance absorbs by measuring the intensity of light as a light beam that passes through a given solution.
The instrument used in Spectrophotometry
Spectrophotometer
The basic principle behind spectrophotometry
Each compound absorbs or transmits light at a certain range of wavelength
Ultraviolet-Visible Spectrophotometer
A spectrometer that makes a sample absorbs light near the ultraviolet region
Colometric Assays
These are used to measure the amount of light transmitted through a sample at a given wavelength.
Wavelength range of ultraviolet
185-400nm
Wavelength range of visible light
400-700nm
Wavelength of infrared light
700-1500nm
Essential parts of a UV-VIS Spectrometer
White light source, Monochromator, Sample Compartment, Detector, and Readout Device
Monochromator
It is used to disperse light into its component wavelength
Sample Compartment
It holds the transparent tube or cell containing the sample
Detector
It measures the amount of light transmitted
Readout Device
It displays the readings of the Spectrophotometer
Tungsten Lamp and Deuterium Lamp
Visible region ; Ultraviolet region
Transmittance
The ratio of the intensity of transmitted light to the incident light
Absorbance
The amount of light absorbed by a sample
Beer-Lambert’s Law
The determination of the concentration of the absorbing species in the analyte solution. It states that the intensity of transmitted light decreases exponentially as any one of these factors increases.
