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There are several column types, according to their function, they can be classified as: a) Normal phase In this column type, the retention is governed by the interaction of the polar parts of the stationary phase and solute. For retention to occur in normal phase, the packing must be more polar than the mobile phase with respect to the sample. Therefore, the stationary phase is usually silica and typical mobile phases are hexane, methylene chloride, chloroform, diethyl ether, and mixtures of these. b) Reverse phase In this column the packing material is relatively nonpolar and the solvent is polar with respect to the sample. Retention is the result of the interaction of the nonpolar components of the solutes and the nonpolar stationary phase. Typical stationary phases are nonpolar hydrocarbons, waxy liquids, or bonded hydrocarbons (such as C18, C8, etc.) and the solvents are polar aqueous-organic mixtures such as methanol-water or acetonitrile-water. c) Size exclusion In this column type, molecules are separated according to size. Small molecules penetrate into the pores within the packing while larger molecules only partially penetrate the pores. The large molecules elute before the smaller molecules. d) Ion exchange In this column type the sample components are separated based upon attractive ionic forces between molecules carrying charged groups of opposite charge to those charges on the stationary phase. Separations are made between a polar mobile liquid, usually water containing salts or small amounts of alcohols, and a stationary phase containing either acidic or basic fixed sites. This HP 1090 Chromatograph is also equipped with an oven in the column compartment. The function of the oven is to provide an homogeneus air-bath temperature when it is required for some methods, such as the carbohydrate separation method which requires a constant temperature of 85ºC.

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What is the difference ods and ods2 HPLC Column?

BDS - Base deactivated Silanol ODS - Octadecyl silane by using the BDS column, residual silanols deacivated and silanol activity reduced, it is end-capped column and it is good for basic compounds. ODS is normal column and high acidic silica, it is not suitable for basic compounds.


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 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.


How do you calibrate for HPLC?

standards are run with samples i.e. several solutions of chemical you are trying to analyse for, of known composition and strengths are run to set up a calibration curve which should be a straight line - absorbance (or signal strength) vs. conc. You then test the unknown sample and can extraploate the concentration of the sample based on your calibration curve. HPLC columns come with a standard chromatogram when purchased so a run with same conditions and sample should give similar retention times.


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.

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What are the columns used in hplc?

* large columns, specifically for packing. * analytical columns, for quantitative analysis, usually accompanied by a UV-vis detector. * Narrow bore columns, for more sensitive analysis * capillary columns, very this silica columns used almost exclusively with GC mass spectroscopy. * packed bed columns. with silica beads. and may have groups attached, e.g. C18.


What has the author Harold M McNair written?

Harold M McNair has written: 'Direct coupling of microbore HPLC columns to MS systems'


What are the different types of absorption column?

Major types of Absorption columns are liquid-liquid absorption columns, Gas-liquid absorption columns.


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The Greeks have different types of columns for different types of places. Doric columns were the shortest and plainest, Ionic columns were slightly fancier and taller than Doric columns, and Corinthian columns were the most elaborate and tallest.


What is the difference ods and ods2 HPLC Column?

BDS - Base deactivated Silanol ODS - Octadecyl silane by using the BDS column, residual silanols deacivated and silanol activity reduced, it is end-capped column and it is good for basic compounds. ODS is normal column and high acidic silica, it is not suitable for basic compounds.


What is difference between uplc and hplc?

A UPLC (ultra-high performance liquid chromatography) is a variant of HPLC using columns with particle size <2 um (typically, 1.8 um), which provides significantly better separation than the traditional (5 um) columns and enables much faster analysis. Strictly speaking, "UPLC" is Waters Corporation trademark, but is often used as a name for the technique in general.


looking for wood columns in the kansas area?

For beautiful wooden columns in many different styles and wood types, log onto: http://www.aicmillworks.com/ They will deliver directly to you.


What types of buffer are used for hplc?

Common types of buffers used for HPLC include phosphate buffers, acetate buffers, citrate buffers, and ammonium acetate buffers. These buffers help to maintain the pH of the mobile phase, stabilize analytes, and provide consistent elution profiles. It's important to choose the right buffer based on the pH requirements of the analytes being analyzed.


What are the different types of columns?

Major types of Absorption columns are liquid-liquid absorption columns, Gas-liquid absorption columns.


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 AUFS in hplc?

AUFS stands for Agilent Universal Fit Sample loop. It is a type of sample loop used in high-performance liquid chromatography (HPLC) systems. AUFS sample loops are designed to be compatible with various types of HPLC systems, providing flexibility and ease of use.