Analytical Chemistry: Retention Times in HPLC Chromatography

  • Thread starter RanCohen
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This is why in reversed phase chromatography, a more polar solvent results in a longer retention time for the analyte. In summary, in reversed phase chromatography, the more polar the solvent, the longer the retention time of the analyte due to increased competition with the non-polar stationary phase.
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RanCohen
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hi everyone,
nowadays i studing pharmaceutical engineering in 3rd year, i don't know if this is the place to ask...
my question is in hplc reversed phase chromatography, i already understand that the stationary phase is non-polar. why, when if the solvent is more polar, the retaintion time of the analyte is longer?
i asumed that is because the hidrophobic solvent taking place of the analyte and if is taking less places (if the solvent more polar) that cause the analyte interact with the stationary phase and come out from column after longer time.

Thank's ran
 
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co.Yes, your assumption is correct. The stationary phase of reversed phase chromatography is non-polar, so the more polar the mobile phase is, the more it will compete with the analyte for the non-polar sites on the stationary phase. This increases the amount of time it takes for the analyte to elute from the column and thus increases its retention time.
 

What is the purpose of retention times in HPLC chromatography?

The retention time in HPLC chromatography is a measure of the time it takes for a compound to travel through the chromatography column and reach the detector. It is used to identify and quantify the components of a sample, as each compound has a unique retention time based on its chemical properties.

How is retention time determined in HPLC chromatography?

Retention time is determined by the interactions between the sample components and the stationary phase of the chromatography column. Compounds that have stronger interactions with the stationary phase will have longer retention times, while those with weaker interactions will have shorter retention times.

What factors can affect retention times in HPLC chromatography?

Retention times can be affected by various factors, including the composition and temperature of the mobile phase, the type and condition of the stationary phase, and the chemical properties of the sample components. Changes in these factors can lead to variations in retention times and affect the accuracy of the analysis.

How can retention times be optimized in HPLC chromatography?

To optimize retention times, it is important to choose the appropriate mobile phase and stationary phase for the sample components. Adjusting the composition and temperature of the mobile phase can also help to improve retention times. Additionally, proper equilibration of the column and ensuring consistent column temperature can aid in obtaining reliable retention times.

Why is it important to monitor and track retention times in HPLC chromatography?

Monitoring and tracking retention times is essential for verifying the accuracy and reproducibility of the analysis. It allows for the identification and quantification of sample components, and any variations in retention times can indicate changes in the sample or experimental conditions. Retention times can also be used to compare results from different analyses and ensure consistency.

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