2012-3. Why Does an Improvement Make Things Worse?

The LC Troubleshooting Bible

← Back to the LC Troubleshooting Bible Contents

2012-3. Why Does an Improvement Make Things Worse?

March 1, 2012

Changing to a “better” liquid chromatography column may not always produce the expected results.

LCGC 30(3) 216-222 (2012)
John W. Dolan

Tags: column dimensions, extracolumn effects, k-values, peak shape

The LC Troubleshooting Bible Archives

or
Find Posts by Tag

2022-5. Dealing with Wandering First-Dimension Peaks in 2D-LC Separations

2022-4. Essentials of LC Troubleshooting, Part II: Misbehaving Retention Times

2022-3. But Why Doesn’t It Get Better? Kinetic Plots for Liquid Chromatography, Part III: Pulling It All Together

2022-2. But Why Doesn’t It Get Better? Kinetic Plots for Liquid Chromatography, Part II: Making and Interpreting the Plots

2022-1. But Why Doesn’t It Get Better? Kinetic Plots for Liquid Chromatography, Part I: Basic Concepts

2021-12. Essentials of LC Troubleshooting, Part I: Pressure Problems

2021-11. But My Peaks Are Not Gaussian! Part III: Physicochemical Causes of Peak Tailing

2021-10. Retention Factor Is Independent of Pressure in LC, Right?

2021-9. But My Peaks Are Not Gaussian! Part II: Physical Causes of Peak Asymmetry

2021-8. But My Peaks Are Not Gaussian! Part I: Basic Concepts in Peak Shape, and the Effect of Extracolumn Connections

2021-7. Where Has My Efficiency Gone? Impacts of Extracolumn Peak Broadening on Performance, Part IV: Gradient Elution, Flow Splitting, and a Holistic View

2021-6. Where Has My Efficiency Gone? Impacts of Extracolumn Peak Broadening on Performance, Part III: Tubing and Detectors

2021-5. Where Has My Efficiency Gone? Impacts of Extracolumn Peak Broadening on Performance, Part II: Sample Injection

2021-4. Where Has My Efficiency Gone? Impacts of Extracolumn Peak Broadening on Performance, Part I: Basic Concepts

2021-3. Surfing on Mobile Phase, Part II: Impact of Mobile-Phase Composition Waves on Retention in LC

2021-2. Surfing on Mobile Phase, Part I: Origins of Mobile-Phase Composition Waves and Their Effects on Detector Baselines

2021-1. LC Troubleshooting Odds and Ends from 2020

2020-12. Tips for Liquid Chromatography Coupled with Charged Aerosol Detection

2020-11. Troubleshooting for Two-Dimensional Liquid Chromatography: Breakthrough in the Second Dimension

2020-10. Troubleshooting 101: Some Essential Principles of Effective Troubleshooting

2020-9. Rules of Thumb for Reversed-Phase LC: What’s In Your Chromatographic Mind?

2020-8. Troubleshooting LC Separations of Biomolecules, Part II: Passivation and Mobile-Phase Additives

2020-7. Recovering from a COVID-19 Shutdown: Tips and Tricks for Starting Up, Part II

2020-6. Recovering from a COVID-19 Shutdown: Tips and Tricks for Starting Up, Part I

2020-5. Liquid Chromatography at Room Temperature: When Should the Column Temperature Be Specified in a Method?

2020-4. Selectivity in Reversed-Phase Liquid Chromatography: 20 Years of the Hydrophobic Subtraction Model

2020-3. Troubleshooting LC Separations of Biomolecules, Part I: Background, and the Meaning of Inertness

2020-2. Effects of Buffer Capacity in LC, Part II: Visualization of pH Changes Inside the Column

2020-1. Effects of Buffer Capacity in Reversed-Phase Liquid Chromatography, Part I: Relationship Between the Sample- and Mobile-Phase Buffers

2019-12. Effects of Flow Rate on UV Detection in Liquid Chromatography

2019-11. Column Re-equilibration Following Gradient Elution: How Long is Long Enough? Part I: Reversed-phase and HILIC Separations of Small Molecules

2019-10. Minimizing Fluctuating Peptide Retention in 2D-LC: How to Address a Moving Target

2019-9. Mind the Diluent: Effects of Sample Diluent on Analyte Recovery in Reversed-Phase and HILIC Separations

2019-8. Pass the Salt: Evolution of Coupling Ion-Exchange Separations and Mass Spectrometry

2019-7. Mobile Phase Buffers in LC: Effect of Buffer Preparation Method on Retention Repeatability

2019-6. Mixing and Mixers in Liquid Chromatography, Part III: Solutions for Problems with Sample Diluents

2019-5. Methods from Mars? Coping with Chromatographic Legacies

2019-4. Reversed-Phase Liquid Chromatography and Water, Part II: Re-equilibration of the Stationary Phase Following Gradient Elution

2019-3. Looking for New Selectivity in Reversed-Phase Liquid Chromatography? A View of the Selectivity Landscape Over the Past Two Years

2019-2. Reversed-Phase Liquid Chromatography and Water, Part I: How Much is Too Much?

2019-1. What’s Trending in LC Troubleshooting?

2018-12. Letting the Chromatograph Talk, Part I: Looking for Troubleshooting Clues in Unexpected Places

2018-11. Mixing and Mixers in Liquid Chromatography—Why, When, and How Much? Part II, Injections

2018-10. Mixing and Mixers in Liquid Chromatography—Why, When, and How Much? Part I, The Pump

2018-9. Tips, Tricks, and Troubleshooting for Separations of Biomolecules, Part II: Contemporary Separations of Proteins by Size-Exclusion Chromatography

2018-8. Contaminants Everywhere! Tips and Tricks for Reducing Background Signals When Using LC–MS

2018-7. Tips, Tricks, and Troubleshooting for Separations of Biomolecules, Part I: Contemporary Reversed-Phase Protein Separations

2018-6. Peak Purity in Liquid Chromatography, Part III: Using Two-Dimensional Liquid Chromatography

2018-5. Fittings and Connections for Liquid Chromatography—So Many Choices!

2018-4. Peak Purity in Liquid Chromatography, Part II: Potential of Curve Resolution Techniques

2018-3. Eluent Preparation for Hydrophilic Interaction Liquid Chromatography, Part II: pH, Buffers, and Gradient Elution

2018-2. Peak Purity in Liquid Chromatography, Part I: Basic Concepts, Commercial Software, and Limitations

2018-1. Eluent Preparation for Hydrophilic Interaction Liquid Chromatography, Part I: Solvent Volumes and Buffer Counterions

2017-12. Resources for LC Practitioners in 2017: What’s on Your Bookshelf and in Your Web Browser?

2017-11s. The Best of LC Troubleshooting: A Farewell to John Dolan

2017-10a. 34 Years of LC Troubleshooting: An Interview with John Dolan

2017-10. All’s Well That Ends Well

2017-9. How to Take Maximum Advantage of Column-Type Selectivity

2017-8. Method Adjustment for Gradient Elution

2017-7. Column Care for the Long Haul — Considerations for Column Storage

2017-6. Method Adjustment the USP Way

2017-5. Count the Cost, Part III: Increasing Resolution by Changing Selectivity

2017-4. Count the Cost, Part II: Increasing Resolution by Increasing Retention

2017-3. Count the Cost, Part I: Increasing Resolution by Increasing Column Efficiency

2017-2. Filters and Filtration in Liquid Chromatography — What to Do

2017-1. Back to Basics: The Role of pH in Retention and Selectivity

2016-12. Failed System Suitability Test: A Case Study

2016-11. Reader’s Question: Early Eluted Peak

2016-10. Reader’s Questions: Gradient Ghost Peaks

2016-9. How Does It Work? Part V: Fluorescence Detectors

2016-8. How Does It Work? Part IV: Ultraviolet Detectors

2016-7. How Does It Work? Part III: Autosamplers

2016-6. How Does It Work? Part II: Mixing and Degassing

2016-5. How Does It Work? Part I: Pumps

2016-4. Retention Time Drift — A Case Study

2016-3. Column Plate Number and System Suitability

2016-2. Detective Work, Part IV: Chemical Problems with the Column — Chemical Attack

2016-1. Detective Work, Part III: Strong Retention and Chemical Problems with the Column

2015-12. Detective Work, Part II: Physical Problems with the Column

2015-11. Detective Work, Part I: Simplify the Choices

2015-10. How to Reduce Mobile-Phase Consumption

2015-9. LC Column Problems Everywhere

2015-8. Overload in Liquid Chromatography

2015-7. Distorted Peaks — A Case Study

2015-6. Internal Standard Calibration Problems

2015-5. Calibration Problems — A Case Study

2015-4. Be Careful of the Flow Rate

2015-3. Listen to the Data

2015-2. Slow Column Equilibration

2015-1. Seven Things to Avoid in the Liquid Chromatography Laboratory

2014-12. Column Protection: Three Easy Steps

2014-11. How Much Can I Inject? Part II: Injecting in Solvents Other than Mobile Phase

2014-10. How Much Can I Inject? Part I: Injecting in Mobile Phase

2014-9. Estimating Resolution for Marginally Separated Peaks

2014-8. How Much Retention Time Variation is Normal?

2014-7. Mobile-Phase Degassing: What, Why, and How

2014-6. UV Detector Problems

2014-5. Readers’ Questions: Calibration

2014-4. Problems with Large-Molecule Separations

2014-3. LC Method Scaling, Part II: Gradient Separations

2014-2. LC Method Scaling, Part I: Isocratic Separations

2014-1. Column Dead Time as a Diagnostic Tool

2013-12. Peak Fronting . . . Some of the Time

2013-11. What’s the Problem with the LLOQ – A Case Study

2013-10. Past, Present, and Future – 30 Years of LC Troubleshooting

2013-9. Variable Retention Times – A Case Study

2013-8. Gradient Elution, Part VI: Ghost Peaks

2013-7. Gradient Elution, Part V: Baseline Drift Problems

2013-6. Gradient Elution, Part IV: Dwell-Volume Problems

2013-5. Gradient Elution, Part III: Surprises

2013-4. Gradient Elution, Part II: Equivalent Separations

2013-3. Gradient Elution, Part I: Intuition

2013-2. The Importance of the Sample Matrix

2013-1. Making the Most of a Gradient Scouting Run

2012-12. Avoiding Refractive Index Detector Problems

2012-11. Evaluation of an LC Method

2012-10. The Role of the Injection Solvent

2012-9. Reader’s Questions

2012-8. Questions from Afar