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News Release from: Selerity Technologies | Subject: Separation of retinol and retinyl esters
Edited by the Manufacturingtalk Editorial
Team on 05 August 2005
Separation of retinol and retinyl esters
A new application note is available free of charge from Selerity Technologies to describe the improvements in separation time and performance by using sub-ambient temperatures.
Typically, a solvent gradient is used to resolve all forms of vitamin A in a single HPLC analysis as the polarity range is large The Polaratherm Total Temperature Controller from Selerity Technologies Inc (Salt Lake City, Utah) has demonstrated optimised results in the separation of vitamin A in biological samples by using a sub-ambient temperature program
This article was originally published on Manufacturingtalk on 7 Aug 2003 at 8.00am (UK)
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A new application note is available free of charge from Selerity Technologies to describe the improvements in separation time and performance by using sub-ambient temperatures.
The application note is available directly from Selerity Technologies, please request application number 813.
For difficult separations such as retinols and retinyl esters, a sub-ambient temperature program has proven an effective method to achieve more efficient peaks and resolution.
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Retinyl acetate and retinyl palmitate are both used for food fortification and Vitamin A supplementation.
Retinyl acetate does not occur naturally in biological tissues, but is often used as an internal standard in HPLC analysis of vitamin A because it has the same absorbance characteristics, is inexpensive and readily available.
In biological samples, vitamin A exists as the free alcohol (retinol) and its esters with long-chain fatty acids (predominantly retinyl palmitate and retinyl stereate).
In most biological tissues, for example liver and kidney, the esters dominate, whereas high ester concentration in plasma is diagnostic of hypervitaminosis A.
One separation was done at ambient temperature and one was performed using a sub-ambient temperature program.
The temperature program was started at 0oC, holding for one minute, ramping to 35oC over six minutes, holding for 0.1 minutes, then ramping to 45oC over ten minutes, and holding at 45oC until the end of the run.
Using the temperature program, a 60% reduction in analysis time and much sharper peaks for all analytes were attained.
Selerity's Polaratherm is a HPLC column compartment capable of controlling the temperature from sub zero to 200 deg C benefiting from two modes of operation, temperature programming and isothermal.
It is the first column compartment that allows and regulates high, ambient, low or dynamic temperatures for selectivity tuning and improved HPLC separations.
This equipment is applicable to most vendor HPLC systems and can be deployed in any laboratory already operating HPLC at little additional cost.
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