The Troubleshooting and Maintenance Guide for Gas Chromatographers

About this book

This fourth edition of the classic guide for every user of gas chromatographic instrumentation is now updated to include such new topics as fast GC using narrow, short columns, electronic pressure control, and basic aspects of quantitative gas chromatography.

The author shares his many years of experience in technical support for gas chromatography users, addressing the most common problems, questions and misconceptions in capillary gas chromatography. He structures and presents the material in a concise and practical manner, suitable even for the most inexperienced user without any detailed knowledge of chemistry or chromatography.

For lab technicians in chemistry, analytical, food, medicinal and environmental chemists, pharmaceutists.

Contents

Preface.Intentions and Introduction.1 Introduction to Capillary Gas Chromatography.1.1 What Is Gas Chromatography?1.2 What Types of Compounds Are Suitable for GC Analysis?1.3 The Basic Parts of a Gas Chromatograph.1.4 The Chromatogram.1.5 The Mechanism of Compound Separation.1.6 Factors Affecting Separation.2 Basic Definitions and Equations.2.1 Why Bother?2.2 Peak Shapes.2.3 Retention.2.4 Phase Ratio (beta).2.5 Distribution Constant (KC).2.6 Column Ef. ciency.2.7 Utilization of Theoretical Ef. ciency (UTE%).2.8 Separation Factor (alpha).2.9 Resolution (R).2.10 Trennzahl (TZ).2.11 Column Capacity.3 Capillary GC Columns: Tubing.3.1 Fused Silica Capillary Columns.3.2 Fused Silica Tubing.3.3 Outer Coating.3.4 Other Tubing Materials.3.5 Polyimide Fused Silica Tubing Bending Stress.4 Capillary GC Columns: Stationary Phases.4.1 Stationary Phases.4.2 Types of Stationary Phases.4.3 Characteristics of Stationary Phases.4.4 Stationary Phase Interactions.4.5 Stationary Phase Equivalencies.4.6 Column Temperature Limits.4.7 Column Bleed.4.8 Selecting Stationary Phases.5 Capillary GC Columns: Dimensions.5.1 Introduction.5.2 Column Length.5.3 Column Diameter.5.4 Column Film Thickness.5.5 Manipulating Multiple Column Dimensions.6 Carrier Gas.6.1 Carrier Gas and Capillary Columns.6.2 Linear Velocity versus Flow Rate.6.3 Controlling the Linear Velocity and Flow Rate.6.4 Van Deemter Curves.6.5 Carrier Gas Measurements.6.6 Carrier Gas Selection.6.7 Recommended Average Linear Velocities.6.8 Gas Purities.6.9 Common Carrier Gas Problems.7 Injectors.7.1 Introduction.7.2 The Basics of Vaporization Injectors.7.3 Split Injectors.7.4 Splitless Injectors.7.5 Direct Injectors.7.6 Cool On-Column Injectors.7.7 Pressure and Flow Programmable Injectors.7.8 Injection Techniques.7.9 Autosamplers.7.10 Injector Septa.7.11 Injector Maintenance.8 Detectors.8.1 Introduction.8.2 Detector Characteristics.8.3 Flame Ionization Detector (FID).8.4 Nitrogen-Phosphorus Detector (NPD).8.5 Electron Capture Detector (ECD).8.6 Thermal Conductivity Detector (TCD).8.7 Flame Photometric Detector (FPD).8.8 Mass Spectrometers (MS).9 Column Installation.9.1 Importance of a Properly Installed Column.9.2 Installing Fused Silica Capillary Columns.9.3 Column Ferrules.9.4 Tightening Fittings.9.5 Techniques for Measuring Column Insertion Distances.9.6 Leak Detection.10 Column Test Mixtures.10.1 Column Performance Testing.10.2 Column Test Mixture Compounds.10.3 Column Testing Conditions.10.4 Grob Test.10.5 Own Test Mixture.10.6 When to Test a Column.11 Causes and Prevention of Column Damage.11.1 Causes of Column Damage and Performance Degradation.11.2 Column Breakage.11.3 Thermal Damage.11.4 Oxygen Damage.11.5 Chemical Damage.11.6 Column Contamination.11.7 Solvent Rinsing Columns.11.8 Guard Columns and Retention Gaps.11.9 Packed Injector Liners.11.10 Gas Impurity Traps.11.11 Column Storage.11.12 Column Repair.12 Troubleshooting Guidelines, Approaches and Tests.12.1 Introduction.12.2 Approaches to Solving GC Problems.12.3 Troubleshooting Tools.12.4 Troubleshooting Tests.13 Common Capillary GC Problems and Probable Causes.13.1 Using This Troubleshooting Guide.13.2 Troubleshooting Checklist and Pre-Work.13.3 Baseline Problems.13.4 Peak Shape Problems.13.5 Split Peaks.13.6 Negative Peaks.13.7 Excessively Broad Solvent Front.13.8 Loss of Resolution.13.9 Retention Changes.13.10 Peak Size Problems.13.11 Extra or Ghost Peaks (Carryover).13.12 Rapid Column Deterioration.13.13 Quantitation Problems.Appendix A Terms.Appendix B Equations.Appendix C Mass, Volume and Length Unit Conversions.Appendix D Column Bleed Mass Spectra.Appendix E The Basics of High Speed GC Using Small Diameter Columns.E.1 Introduction.E.2 Column Considerations.E.3 Carrier Gas Considerations.E.4 Injector Considerations.E.5 Detector and Data System Considerations.E.6 GC Oven Considerations.E.7 Sample Considerations.E.8 An Example of High Speed GC Using a Small Diameter Column.E.9 High Speed GC Summary.Appendix F Basic Quantitative Capillary GC.F.1 Intentions.F.2 De. nitions.F.3 Concentration.F.4 Density (rho).F.5 Calibration for Quantitative Purposes.F.6 Quantitation Calculations.F.7 Techniques for Preparation of Analytical Standards for GC.References.Subject Index.

Customer Reviews

Biography

Dean Rood is now an independent consultant after working as the Manufacturing Engineering Manager at the capillary GC column manufacturing facility of Agilent Technologies in Folsom California. Prior to holding this position, Dean was an Applications and Technical Support Chemist for 11 years. Dean has presented over 500 classes, seminars and papers on GC and related chromatographic techniques. He is an Associate Editor of the Journal of Chromatographic Science, co-writes the monthly column on GC Troubleshooting and Problem Solving, and has authored numerous papers and book chapters on analytical chromatography. Prior to joining the former J&W Scientific in 1987, Dean was an analytical chemist at the College of Veterinary Medicine, University of Illinois. Dean received a BS in chemistry from the University of Illinois, Urbana-Champaign in 1983.