29 Questions
What type of lamps are used in UV-Visible spectrophotometry?
Deuterium and tungsten filament
In which wavelength range does colorimetry mainly work?
400-700 nm
What is the purpose of a monochromator in a UV-Visible spectrophotometer?
To separate polychromatic light into monochromatic light
Why are colorimeters considered cheap and easy to operate?
Due to the use of simple narrow band filters
Which region of the electromagnetic spectrum do UV-visible spectrophotometry and colorimetry cover?
UV to visible region
Why are UV-Visible spectrometers more expensive compared to colorimeters?
They are equipped with two different lamps
What is the wavelength of maximum absorption known as?
Lambda max (λmax)
In the UV-visible spectrum of lycopene, what is the lambda max value?
471 nm
What does the detector in a UV/VIS spectrophotometer or colorimeter measure?
Intensity of transmitted light
What is the ratio between the intensities I / I0 defined as?
Transmittance T
Which law is applied for quantification based on the absorptivity of pure compounds?
Beer-Lambert Law
What term refers to the attenuation of transmitted light by sample molecules in solution?
''Transmittance T''
What can happen if the molecules in a solution are at high concentrations?
They aggregate, leading to incorrect readings
Why is it essential for the solution not to contain molecules that emit fluorescence when excited?
To avoid erroneous readings
What is necessary for determining the concentration of an unknown sample using UV/VIS spectroscopy?
Creating a calibration curve
How is a calibration line obtained for UV/VIS spectroscopy analysis?
Linear regression of absorbance values
What does the Lambert-Beer Law form the basis for in UV/VIS spectroscopy?
Determining unknown sample concentrations
What purpose do UV/VIS spectra serve in identifying components in a sample solution?
Identifying sample components
What allows specific compounds to be identified in UV/VIS spectroscopy?
Position and profile of the absorption peaks
How is the blank in UV/VIS spectroscopy typically measured?
Intensity of light transmitted through the solvent
What is the purpose of measuring the absorbance value of a peak in UV/VIS spectroscopy?
To calculate the sample concentration
Why is a blank measurement necessary in UV/VIS spectroscopy?
To measure the intensity of transmitted light through the solvent
In which market segments is UV/VIS spectroscopy commonly used as a quantitative analytical technique?
Water Testing, Food and Beverages, Pharmaceutical, Chemical and Biotech Industry
What is added to a cuvette for blank measurement in UV/VIS spectroscopy?
Solvent like water or alcohol
How is absorbance calculated in a spectrophotometer?
By dividing the transmitted intensity of the sample solution by the corresponding values of the blank
What is the purpose of using absorbance values for standard solutions in spectrophotometry?
To plot the calibration curve
Why is it important to measure absorbance in a spectrophotometer?
To quantify the amount of light absorbed by sample molecules
What role do standard solutions play in UV/VIS spectrophotometric analysis?
They aid in plotting calibration curves
Why is it necessary to extrapolate concentrations from a calibration curve in spectrophotometry?
To quantify unknown sample concentrations
Learn about the fundamental principles and applications of UV-Visible spectrophotometry and colorimetry in chemical analyses. This module covers the similarities between these analytical techniques and their significance in both qualitative and quantitative measurements.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
