Table of Contents
- 1 Why are mixtures of solvents used in HPLC?
- 2 How does HPLC differ from GC?
- 3 Which solvent is used in HPLC?
- 4 How do I remove air from HPLC?
- 5 Why use GC not HPLC?
- 6 How does temperature affect gas chromatography?
- 7 What’s the difference between HPLC and GC sample separation?
- 8 Do you need HPLC to analyze volatile compounds?
Why are mixtures of solvents used in HPLC?
Binary solvent mixtures are used as carriers in HPLC columns to extract drugs and drug precursors during the manufacturing process. Accurate control of the composition of the mixture is crucial for accurate and efficient separation of the desired pharmaceutical compounds.
Why is it necessary to remove gas bubbles or Degas the mobile phase in HPLC operation?
Air bubbles can also modify the flow of mobile phase through the column due to the creation of dead volumes. In HPLC analysis the problems produced by bubble formation can largely be prevented, by degassing the mobile phase.
How does HPLC differ from GC?
HPLC uses a solvent for the mobile phase where the polarity, solubility and complexity of the compounds in the sample determine which solvent should be used. On the other hand, GC uses an unreactive or inert gas, also known as the carrier gas.
How does solvent affect gas chromatography?
The solvent effect is used to focus the sample into a tight band at the front of the column. This results in properly formed peaks of acceptable width and shape.
Which solvent is used in HPLC?
Normal Phase HPLC separates the analytes using their varying degree of affinity to the phase which is polar by nature. Non-polar solvents like chloroform, cyclohexane, benzene, carbon tetrachloride etc. are used.
Which detector is used in HPLC?
UV detector is a very commonly used detector for HPLC analysis. During the analysis, sample goes through a clear color-less glass cell, called flow cell. When UV light is irradiated on the flow cell, sample absorbs a part of UV light.
How do I remove air from HPLC?
Turn the handle counterclockwise, about 1/2-turn, to open the valve, and pull back on the plunger to remove air bubbles. Once the air is removed, close the valve and start flow. Flush the system with 100% methanol for a minimum of 30 minutes.
What does a degasser do in HPLC?
The Vacuum Degasser is designed to remove gases from a liquid such as the mobile phase used in HPLC. The following precautions should be followed to minimize the possibility of personal injury and/or damage to property while using the system.
Why use GC not HPLC?
GC is used for volatile compounds (those that break down rapidly) while HPLC is better for less volatile samples. If a sample contains salts or carries a charge, it must be analyzed using HPLC, not GC.
Should I use GC or LC?
Often in cases like this, GC analysis can be done if the compounds are derivatized. Although there are many examples of compounds that can be done either way, LC is considered more universal and generally does not require derivatization as often.
How does temperature affect gas chromatography?
Temperature can affect retention, selectivity and peak shape, as well as column pressure and other less important variables. In gas chromatography separations, temperature is a primary variable used to control the separation, and it acts in a similar capacity as mobile-phase strength in LC.
What is the reversal solvent?
The reverse solvent effect causes distortion (usually extensive tailing) of analyte peaks when the solvent has a later retention time than the analyte. This can also occur when a second analyte is present in excess.
What’s the difference between HPLC and GC sample separation?
As implied by their names, the mobile phase for HPLC is liquid and for GC is gas. Another major difference is that the mobile phase is a key participant in sample separation for HPLC but not for GC. HPLC uses solvent mixtures and gradients.
What’s the difference between GC and carrier gas in HPLC?
To be clear, choosing the mobile phase is a crucial part of HPLC and troubleshooting for better separation is often complex. In contrast, GC uses a pure inert gas as the mobile phase. It’s commonly known as the carrier gas because its purpose is to carry molecules through the column.
Do you need HPLC to analyze volatile compounds?
Now, your other option is HPLC. You can analyze volatile and non-volatile compounds, from low to high molecular weights, as long as they are soluble in a liquid phase. Also, you don’t need to worry about thermal stability since samples usually run at room temperature.
What’s the difference between HPLC and liquid chromatography?
HPLC is high performance liquid chromatography. It is a type of column chromatography. This technique includes pumping the sample with solvent (the sample to be separated) into a column at high pressure. The column contains the stationary phase (not moving) which is a solid adsorbent.