Protein Separation Techniques

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Where do ions enter in an Orbitrap analyser?

Perpendicular to the axis

Off-axis (correct)

At an angle of 45 degrees

On-axis

What is the primary factor affecting the time of flight in time-of-flight mass spectrometry?

Charge of the ion

Size of the ion

Mass-to-charge ratio of the ion (correct)

Speed of the ion

What is the purpose of additional sample preparation prior to chromatography?

To make the mobile phase more effective

To increase the analysis time

To simplify the matrix (correct)

To increase the accuracy of the results

What is the main advantage of Orbitrap analysers?

Higher accuracy and specificity Signup and view all the answers

What is the primary purpose of selecting the best suitable stationary phase and mobile phase conditions in HPLC?

To get the best possible results Signup and view all the answers

What is the main purpose of chromatofocusing?

To separate proteins based on their isoelectric point Signup and view all the answers

What happens to the ion packets/rings in the Orbitrap analyser?

They oscillate due to the electric field Signup and view all the answers

What is the advantage of using recombinant proteins?

They can be modified to increase production and create useful commercial products Signup and view all the answers

What is the role of ion exchange resins in chromatofocusing?

To bind to proteins based on their surface charge Signup and view all the answers

What is the purpose of desalting in post-chromatography processing?

To remove salts from the protein sample Signup and view all the answers

What is the difference between chromatofocusing and SDS-PAGE?

Chromatofocusing separates proteins based on isoelectric point, while SDS-PAGE separates proteins based on molecular weight Signup and view all the answers

What is the purpose of 2D gel electrophoresis?

To separate proteins based on their isoelectric point and molecular weight Signup and view all the answers

What is the purpose of elution buffer in chromatofocusing?

To elute bound proteins by altering the pH of the buffer Signup and view all the answers

What is the purpose of Western blotting?

To identify specific proteins using antibodies Signup and view all the answers

What is the primary advantage of using supercritical carbon dioxide in decaffeination?

It can penetrate the interior of coffee beans without grinding Signup and view all the answers

What is the purpose of the quadrupole filter in mass spectrometry?

To separate ions based on their mass-to-charge ratios Signup and view all the answers

What is the main limitation of UV/Vis detection?

It is limited by a single absorbance wavelength Signup and view all the answers

What is the purpose of the ion source in mass spectrometry?

To convert molecules into charged ions Signup and view all the answers

What is the main advantage of DAD detection over UV/Vis detection?

It can detect a wide range of wavelengths at one time Signup and view all the answers

What is the purpose of the pump and mixer in small molecule detection?

To deliver the mobile phase to the column Signup and view all the answers

What is the main advantage of triple quadrupole MS over simple MS?

It is more powerful and has a higher accuracy and scan rate Signup and view all the answers

What is the result of the ions and ion fragments reaching the electrostatic detector in mass spectrometry?

A mass spectrum is created Signup and view all the answers

What is one drawback of fluorescent analysis?

Analytes may undergo photochemical reactions at the wavelength of interest Signup and view all the answers

What is the primary use of quenching in molecular imaging?

Förster resonance energy transfer (FRET) assays Signup and view all the answers

What distinguishes chemiluminescence from bioluminescence?

Bioluminescence involves energy release from a biochemical reaction Signup and view all the answers

Which method is used to determine the kinetics of diffusion in living cells?

Fluorescence Recovery After Photobleaching (FRAP) Signup and view all the answers

What type of samples are unsuitable for quantitative analysis using fluorescence?

Colloidal or intransparent samples Signup and view all the answers

Which application is NOT a typical use of quantitative analysis involving fluorescence?

Clinical diagnosis and treatment Signup and view all the answers

What is the term for the difference in band maxima positions between the absorption and emission spectra of the same electronic transition?

Stokes shift Signup and view all the answers

Which substance is correctly matched with its luminescent property?

Firefly - bioluminescence Signup and view all the answers

What property makes gas chromatography ideal for volatile mixtures?

Components can be vaporised without decomposition Signup and view all the answers

What is the role of the carrier gas in gas chromatography?

To transport the vaporised sample through the column Signup and view all the answers

Which of the following detectors is NOT compatible with gas chromatography?

Infrared spectrophotometer (IR) Signup and view all the answers

What effect does a shorter gas chromatography column have on the analysis?

Faster analysis but less resolution Signup and view all the answers

How are components in a sample separated during gas chromatography?

Based on their relative affinity for the stationary phase Signup and view all the answers

What is indicated by the retention time in a chromatogram?

The time taken for a component to pass through the column Signup and view all the answers

Which is a toxic compound that can be formed during coffee roasting?

Furan Signup and view all the answers

What happens to the components of a sample when they exit the column in gas chromatography?

They pass through a detector generating a signal Signup and view all the answers