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Both C8 and C18 columns are considered as examples of reversed phase liquid chromatography (RP). The stationary phase here is seen as a thin film of non-polar liquid phase that has been designed to be chemically anchored to an inert material (Silica gel particles). The non-polar layer is chemically linked to the silica particles surface by reaction with the polar silanol groups on the stationary phase surface and so rendering them (less polar or non-polar), The difference between the two columns will be in the length of the carbon-chain attached to the silica surface. Acoordingly C8 hplc columns have packing material composed of silica particles attached to C8 carbon units while C18 will, of course, have packing materials coated with C18 hydrophobic units. Categorically both are reversed phase but C18 columns will definitely be more "hydrophobic rather than the C8 columns.
What else can I help you with?
Can C18 column for HPLC be used with UV and visible spectra detector and Acetonitril as mobile phase?
Of course.... there isn´t problem....
How do you select hplc column in method development?
firs you mist know the polarity for sample, wen the sample polar you can use "RP" column like C18 or C8 ( C18 first in pharmaceutical) . wen sample non polar use "NP" column like silica or CN Column. after that you can change the column in same packing to solve tailing, retention time, Resolution..... or any problem by change column length, particle size or carbon loud
When you use c8 and when c18 column?
C8 columns are typically used for faster separations at lower resolution when analyzing smaller molecules, while C18 columns are used for higher resolution separations and better separation of complex mixtures, such as peptides and proteins. C18 columns have a higher hydrophobicity and are more suitable for compounds that interact strongly with the stationary phase.
Why is column revers phase in hplc?
Column reverse phase in High-Performance Liquid Chromatography (HPLC) refers to the use of a nonpolar stationary phase and a polar mobile phase. This configuration allows for the separation of compounds based on their hydrophobicity, where more hydrophobic compounds interact more strongly with the stationary phase and elute later. Reverse phase HPLC is widely used because it provides high resolution and sensitivity for a variety of analytes, making it suitable for pharmaceuticals, environmental samples, and biological fluids.
What are all the parameters that have impact on the polarity of C8 and C18 columns?
The key parameters that impact the polarity of C8 and C18 columns are the length of the alkyl chain attached to the silica surface, the mobile phase composition, the pH of the mobile phase, and the column temperature. These factors influence the retention and selectivity of compounds on the stationary phase.
Can you use a C18 column for HPLC with fluorescence detector and methanol as the mobile phase?
Yes, you can use a C18 column and methanol as a mobile phase with fluorescence detector. Fluorescence detector is generally used as it can detect the presence of compounds at a very low concentration.
Can C18 column for HPLC be used with UV and visible spectra detector and Acetonitril as mobile phase?
Of course.... there isn´t problem....
How do you distinguised np-hplc and rp-hplc?
NP-HPLC is "Normal Phase" HPLC, wherein the solvents used are less polar than the substrate in the HPLC column (e.g. using hexane or dichloromethane with a silica HPLC column). RP-HPLC is "Reverse-Phase" HPLC, wherein the solvents used are more polar than the substrate in the HPLC column (e.g. using Water and Methanol with a octadecylsilane (ODS or C18) column).
What is an HPLC column?
HPLC Column is one type of tube containing a stationary phase react with mobile phase to detect peak
Explain the rationale for using a reversed phase C18 column for the determination of caffeine?
A reversed phase C18 column is commonly used for the determination of caffeine due to its hydrophobic properties, which can efficiently separate caffeine from other compounds in the sample based on their differing affinities for the stationary phase. Caffeine, being relatively nonpolar, interacts strongly with the C18 column, allowing for good retention and separation. Additionally, C18 columns are compatible with common mobile phases used in high-performance liquid chromatography (HPLC), making them a popular choice for caffeine analysis.
How do you select hplc column in method development?
firs you mist know the polarity for sample, wen the sample polar you can use "RP" column like C18 or C8 ( C18 first in pharmaceutical) . wen sample non polar use "NP" column like silica or CN Column. after that you can change the column in same packing to solve tailing, retention time, Resolution..... or any problem by change column length, particle size or carbon loud
When you use c8 and when c18 column?
C8 columns are typically used for faster separations at lower resolution when analyzing smaller molecules, while C18 columns are used for higher resolution separations and better separation of complex mixtures, such as peptides and proteins. C18 columns have a higher hydrophobicity and are more suitable for compounds that interact strongly with the stationary phase.
Can you use PBS as mobile phase in C18 column?
Yes, PBS (phosphate-buffered saline) can be used as a mobile phase in a C18 column, particularly for reverse phase chromatography. However, it is important to consider the pH and ionic strength of the PBS, as these factors can influence retention time and separation efficiency. Additionally, the presence of salts in PBS may affect the column’s performance and longevity, so it is advisable to validate the method for specific applications.
What are all the parameters that have impact on the polarity of C8 and C18 columns?
The key parameters that impact the polarity of C8 and C18 columns are the length of the alkyl chain attached to the silica surface, the mobile phase composition, the pH of the mobile phase, and the column temperature. These factors influence the retention and selectivity of compounds on the stationary phase.
What chemistry difference between C18 hplc column while using two different companies?
Dear there is stationary phase in column loaded or paked on silica bed so there may be selectivity difference in columns of two companies and also there carbon load will be differentbyesp goswamiSelectivity will be changed due to their carbon loading and imbedded groups on silica bed, which is confidential by companies.Manoj Parmar
What are the key differences between normal phase HPLC and reverse phase HPLC in terms of their separation mechanisms and applications?
Normal phase HPLC separates compounds based on their polarity, with the stationary phase being polar and the mobile phase being nonpolar. Reverse phase HPLC separates compounds based on their hydrophobicity, with the stationary phase being nonpolar and the mobile phase being polar. Normal phase HPLC is typically used for separating polar compounds, while reverse phase HPLC is used for separating nonpolar compounds.
What is C8 and C18?
C8 and C18 refer to carbon chain lengths in fatty acids. C8 means the fatty acid has 8 carbon atoms in its chain, while C18 means the fatty acid has 18 carbon atoms in its chain. The number of carbon atoms in a fatty acid chain can affect its properties and functions in the body.
