UV-Visible Spectroscopy and Chromatography Basics

β-Carotene appears orange because it absorbs light in the blue region while transmitting light in the red-yellow region.

The main components of a UV-Visible spectrophotometer are the light source, monochromator, sample area, and detector.

UV-Visible spectroscopy assists in enzyme kinetics by providing essential data for the estimation of glucose and tissue damage in clinical diagnostics.

<p>It is used for dissolution testing of tablets and products in the pharmaceutical industry.</p> Signup and view all the answers

<p>This type of spectroscopy is known as infrared (IR) spectroscopy.</p> Signup and view all the answers

<p>A 100 percent transmittance indicates that there is no absorption of IR radiation by the sample.</p> Signup and view all the answers

<p>In environmental studies, UV-Visible spectroscopy is used to quantify organic materials and heavy metals in freshwater.</p> Signup and view all the answers

<p>In the dye and paint industries, UV-Visible spectroscopy is crucial for quality control during the development and production of dyes and inks.</p> Signup and view all the answers

<p>The mobile phase acts as the solvent that moves through the column, facilitating the separation of molecules.</p> Signup and view all the answers

<p>The stationary phase is the solid substance that remains fixed inside the column, allowing for the separation of different components.</p> Signup and view all the answers

<p>Elution is the process of washing out a compound through the column using a suitable solvent mixture.</p> Signup and view all the answers

<p>The speed at which components travel depends on their molecular characteristics related to adsorption and their affinities with the stationary and mobile phases.</p> Signup and view all the answers

<p>An analyte is the substance or mixture of components that needs to be separated and analyzed during chromatography.</p> Signup and view all the answers

<p>The eluent is the fluid entering the column that helps to carry the analytes through the stationary phase for separation.</p> Signup and view all the answers

<p>Separation is influenced by molecular weight, adsorption characteristics, and the affinity between the mixture's components and the stationary or mobile phases.</p> Signup and view all the answers

<p>Some components remain longer in the stationary phase and move slowly, while others move rapidly into the mobile phase and exit the system faster.</p> Signup and view all the answers

<p>The Beer-Lambert Law describes the relationship between absorbance, sample concentration, and pathlength in a light-absorbing medium.</p> Signup and view all the answers

<p>Absorbance (A) is calculated as $A = - ext{log}_{10}(T)$, where T is the transmittance of light through a sample.</p> Signup and view all the answers

<p>The molar absorption coefficient (ε) indicates how strongly a substance absorbs light at a specific wavelength and has units of dm³ mol⁻¹ cm⁻¹.</p> Signup and view all the answers

<p>Molecules must have pi bonds or atoms with non-bonding orbitals to absorb UV light in the range of 200 - 800 nm.</p> Signup and view all the answers

<p>The pathlength (l) refers to the distance that light travels through the sample solution.</p> Signup and view all the answers

<p>An increase in sample concentration (c) leads to an increase in absorbance (A), as they are directly proportional.</p> Signup and view all the answers

<p>UV-Visible spectroscopy measures wavelengths from 160 nm to 780 nm.</p> Signup and view all the answers

<p>Pi bonds and non-bonding orbitals are essential because they enable the electronic transitions necessary for light absorption in UV-Vis spectroscopy.</p> Signup and view all the answers

<p>An absorption peak is a dip in the percent transmittance spectrum caused by the absorption of infrared radiation at characteristic wave numbers by different groups of atoms.</p> Signup and view all the answers

<p>A molecule must have a changing electric dipole moment during vibration to absorb infrared radiation.</p> Signup and view all the answers

<p>Homonuclear diatomic molecules are infrared-inactive because their dipole moment remains zero, regardless of bond length changes.</p> Signup and view all the answers

<p>The two main types of molecular vibrations are stretching vibrations and bending (deformation) vibrations.</p> Signup and view all the answers

<p>For a non-linear molecule with 'n' atoms, the number of fundamental vibration modes is calculated using the formula (3n - 6).</p> Signup and view all the answers

<p>Symmetrical stretching involves equal movement of atoms toward and away from each other, while asymmetrical stretching involves unequal movement where one bond length changes more than the other.</p> Signup and view all the answers

<p>The three fundamental vibration modes of water are symmetric stretching, asymmetric stretching, and bending.</p> Signup and view all the answers

<p>Molecular vibrations change the dipole moments of compounds, allowing them to absorb infrared radiation at specific frequencies.</p> Signup and view all the answers

<p>The pump generates a flow of eluent from the solvent reservoir into the system.</p> Signup and view all the answers

<p>An injector introduces samples using a syringe or through a sampling loop in an autosampler system.</p> Signup and view all the answers

<p>Common packing materials include silica or polymer gels.</p> Signup and view all the answers

<p>The presence of analytes changes the composition of the eluent, which can be measured by the detector.</p> Signup and view all the answers

<p>The detector observes the separation of analytes and measures the differences in eluent composition.</p> Signup and view all the answers

<p>Computer-based data processors, also known as integrators, have largely replaced pen recorders.</p> Signup and view all the answers

<p>High-pressure generation is necessary to ensure that the eluent flows properly through the system.</p> Signup and view all the answers

<p>The column is where the separation of analytes occurs.</p> Signup and view all the answers

<p>The primary function of a degasser is to remove dissolved gases from the eluent to prevent noise and unstable baselines during analysis.</p> Signup and view all the answers

<p>HPLC is used to identify and analyze samples for trace elements and to separate compounds based on their molecular weight.</p> Signup and view all the answers

<p>The polymer membrane tubing contains numerous small pores that allow air to pass through while preventing liquid from escaping.</p> Signup and view all the answers

<p>HPLC is significant in the food industry for detecting food spoilage and identifying additives.</p> Signup and view all the answers

<p>One major application of HPLC in forensic science is analyzing blood and hair samples from crime scenes.</p> Signup and view all the answers

<p>HPLC contributes to molecular biology studies by facilitating the separation and purification of proteins and nucleic acids.</p> Signup and view all the answers

<p>HPLC helps detect polychlorinated biphenyls (PCBs) in various environmental samples.</p> Signup and view all the answers

<p>Baseline stability is crucial as it ensures more accurate measurement of analytes, allowing for reliable analysis results.</p> Signup and view all the answers