Contents
What is the pump in HPLC?
An HPLC pump is also called a “solvent delivery system.” The purpose of the pump is to maintain a constant flow of mobile phase through the HPLC system. This is accomplished regardless of the back pressure caused by the flow resistance of the HPLC column.
How many pumps are in HPLC?
There are three main types of HPLC pumps. Most HPLC pumps are reciprocating pumps. The solvent is drawn into a small chamber (with the solvent check valve open) and pumped out of it (when the column check valve is open) by the back and forth motion of a motor driven piston.
Which pump is not used in HPLC?
Which of the following is not an advantage of Syringe type pumps used in High-pressure liquid chromatography? Explanation: The limitation of Syringe type pump is that it has the limited solvent capacity and is inconvenient when solvents are to be changed.
How pulsation in pumping system is eliminated in HPLC system?
Two chambers are controlled by a single motor by a common eccentric cam. This common motor allows one piston to deliver while the other is refilling the other chamber and vice versa. As a result the pulsations get eliminated to a large extent.
Why C18 column is used in HPLC?
C18 columns are HPLC (high performance liquid chromatography) columns that use a C18 substance as the stationary phase. C18 simply means that the molecules contain 18 carbon atoms, so the other atoms in the molecule can vary, leading to significantly different substances.
What is displacement pump in HPLC?
There are 3 main types of HPLC pumps: Displacement (or syringe) pump – The solvent is pumped out of a large chamber by a plunger (R5 Fig 6.10). The pump produces a pulse-free flow which is also independent of column back pressure and solvent viscosity.
Which column is used in HPLC?
The reversed-phase HPLC column is the most versatile and commonly used column type and can be used for a wide range of different types of analytes. Normal-phase HPLC columns have polar packing. The mobile phase is nonpolar and therefore usually an organic solvent such as hexane or methylene chloride.
How many detectors are there in HPLC?
They are of three types, i.e. fixed wavelength detectors, variable wavelength detectors and the diode array detectors.
Which column is used in SFC?
Mainly supercritical CO2 is used as mobile phase in SFC (Supercritical Fluid Chromatography). It is said suitable for high speed analysis because of lower viscosity than the general HPLC mobile phase and fast diffusion speed is fast in mobile phase.
What is pulse in HPLC?
How does the Pulse Dampener Work in an HPLC Pump? The LO-Pulse Pulse Dampener reduces pulsations by compressing a fluid held within the bottom cavity of the unit (Lo-Pulse looks like a steel hockey puck). This fluid is isolated from the mobile phase by a durable yet flexible inert diaphragm.
Is C18 polar or nonpolar?
A C18 column is an example of a “reverse phase” column. Reverse phase columns are often used with more polar solvents such as water, methanol or acetonitrile. The stationary phase is a nonpolar hydrocarbon, whereas the mobile phase is a polar liquid.
What is difference between C8 and C18 column?
C18 has 18 carbon atoms while C8 has only 8 carbon atoms. C18 has a longer carbon chain, but C8 has a shorter one. C18 has higher retention while C8 has shorter retention. C18 has higher hydrophobicity, but C8 has a lower hydrophobicity.
When to Prime lines in a HPLC pump?
If you have a poor quality (or poorly maintained) system, then you will spend much of your time trying to establish reliable flow through the HPLC system, not running samples. Before using an HPLC system, you should prime all of the lines in your HPLC pump.
Which is the most common type of HPLC pump?
Conventional, analytical HPLC pumps are the most common type, but semi-micro and a preparative pumps are also used depending on the range of the eluent flow rate required. The pump is selected to suit the purpose of the analysis.
What should the back pressure be on a HPLC pump?
The back-pressure shown on the system readout should be very low during this initial priming process (e.g. < 15 bars) as the HPLC system should not be plumbed with the column or detector inline, during the priming process (it should be by-passing those parts) .
What are the fundamentals of the HPLC system?
Modular HPLC System –basic configuration with isocratic pump, manual injector, variable wavelength detector, and hand-held controller Modular HPLC System –high-end configuration with quaternary pump, autosampler, column thermostat, diode array detector, and computer with control and data analysis SW