HPLC Techniques and Applications Quiz

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Questions and Answers

What property benefits from using smaller particles in HPLC?

Increased time for separation

Increased viscosity in the mobile phase

Lower sensitivity

Higher theoretical plates (NTP) (correct)

Which type of chromatography uses a stationary phase that is chemically bonded to a solid support?

Bonded phase chromatography (correct)

Ion-exchange chromatography

Size exclusion chromatography

Affinity chromatography

What is one of the main advantages of HPLC in industrial applications?

Requires minimal operator experience

Lower cost compared to other methods

Provides fast analysis (correct)

Involves simpler instrumentation

Which of these is a limitation of HPLC?

Expensive instrumentation Signup and view all the answers

In which type of chromatography is silica used as the stationary phase?

Adsorption chromatography Signup and view all the answers

What is the primary role of the pump in an HPLC system?

To maintain a constant flow of the mobile phase Signup and view all the answers

What detection limit (LOD) is typically achievable with HPLC?

Around 10-9 g Signup and view all the answers

Which chromatographic technique is characterized by separating based on charge interactions?

Ion-exchange chromatography Signup and view all the answers

What characterizes isocratic elution in RP-HPLC?

Fixed solvent composition Signup and view all the answers

What is one advantage of gradient elution compared to isocratic elution?

Better resolution and shorter separation time Signup and view all the answers

Which detector is most widely used in RP-HPLC for its ability to detect low concentrations of solute?

UV detector Signup and view all the answers

How does increasing the chain length of packing material affect retention in RP-HPLC?

Increases retention Signup and view all the answers

What is a disadvantage of using a refractive index detector in gradient analysis?

Sensitivity to flow rate of column effluent Signup and view all the answers

Which type of elution typically leads to a longer separation time?

Isocratic elution Signup and view all the answers

Which type of detector is highly sensitive to substances that can re-emit absorbed light?

Fluorescence detector Signup and view all the answers

In a gradient elution, what happens to the polarity of the mobile phase?

It decreases gradually. Signup and view all the answers

In normal-phase chromatography, which type of stationary phase is utilized?

Polar stationary phase Signup and view all the answers

What is the elution order of solutes in reverse-phase chromatography?

Most polar solute elutes first Signup and view all the answers

Which mobile phase characteristic leads to increased elution time in reverse-phase chromatography?

Increased polarity of the mobile phase Signup and view all the answers

What happens to highly polar solutes in reverse-phase chromatography?

They bleed the column Signup and view all the answers

Which polar functional group is used in stationary phases for HPLC?

Cyano (–C2H4CN) Signup and view all the answers

What is the primary effect of using a mobile phase with low polarity in normal-phase chromatography?

Decreases solute retention time Signup and view all the answers

Which combination of solvents is commonly used in HPLC for effective separation?

70% ACN and 30% H2O Signup and view all the answers

What defines the reversed-phase separation process in HPLC?

Stationary phase is non-polar and mobile phase is polar Signup and view all the answers

Study Notes

High-Performance Liquid Chromatography (HPLC)

HPLC uses a liquid mobile phase and a stationary phase for separation
Different types of chromatography include partition, adsorption, ion-exchange, size exclusion, affinity, and chiral chromatography
HPLC utilizes various stationary phases tailored to different analyte types (e.g., organic soluble or water soluble)
Separation mechanism in HPLC is based on different interactions between analytes and stationary phases
Smaller particle size in HPLC columns leads to higher efficiency (number of theoretical plates) but higher pressure requirements
Early HPLC used larger particles and lower pressures
Instrumentation typically includes pumps, a sample injection valve, a column, a detector, and a data recording system
HPLC separation is monitored continuously and in real time using a detector
Mobile phase is typically a liquid containing solvents
The choice of mobile phase affects elution order and separation
A normal-phase separation uses a polar stationary phase and a non-polar mobile phase
In a reverse phase separation, a non-polar stationary phase is used along with a polar mobile phase
The selection of solvents and their proportion (composition) during the separation is crucial
Stationary phases are often highly pure, spherical, and microporous materials, permeable to solvents
Stationary phases include silica or polymeric materials like polystyrene; bare silica is suitable for adsorption chromatography
Bonded stationary phases are commonly used, where a functional group is covalently attached to the silica surface
HPLC can often separate molecules with similar properties or structures
Commonly used detectors are UV and fluorescence detectors that measure absorption and emission properties.
There are also refractive index detectors
Gradient elution generally improves separation efficiency
Chain length on stationary phase significantly affects the retention time of the analytes
High polarity mobile phases used first, decreasing polarity subsequently (gradient elution)
Isotachophoresis is not applicable to the same degree for HPLC

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Description

Test your knowledge on High-Performance Liquid Chromatography (HPLC) with this quiz. Explore concepts such as detection limits, stationary phases, and elution techniques. Perfect for students studying analytical chemistry!