Open Tubular Column Gas Chromatography in Environmental Sciences

The method of choice for analysis of organic pollutants in the environ­ ment is gas chromatography, using one of the most common detection systems such as flame ionization, electron capture, and mass spectro­ metric detection. Perhaps the most prevalent difference in practice among the envi­ ronmental analytical chemists involves the type of column used in gas chromatography. The traditional packed-column gas chromatography is rapidly being replaced with wall-coated open tubular (WCOT) columns. However, in using WCOT columns there are difficulties in reporting analytical data and the means of quantitation. This book is intended to present a survey of the salient features of WCOT column gas chromatography that relate to the selection ofWCOT columns, their technology, separation efficiency, and determination of the principal groups of organic micropollutants, such as hydrocarbons, aromatics, polynuclear aromatic hydrocarbons, organochlorine pollu­ tants, chlorinated phenols, dioxins, dibenzofurans, ureas, carbamates, and odor-causing substances in complex environmental matrices. Hence, it is the hope of the authors that the content of this book will be of significance to a wide spectrum of disciplines that include environmental chemistry, industrial hygiene and health, toxicology, genetics, and in­ dustry.

One: Introduction.- 1.1. Organic Contaminants in the Environment.- 1.2. Advances of Trace Organic Analysis.- 1.2.1. Separation Methods.- 1.2.2. Historical Development of WCOT Column Gas Chromatography.- 1.3. Nomenclature and Relationships in Gas Chromatography.- 1.4. Separation Number (Trennzahl).- 1.4.1. Required Column Parameters.- 1.4.2. Minimum Analysis Time.- 1.4.3. Column Length.- 1.5. Thermodynamic Concept of Polarity and Selectivity.- 1.5.1. Polarity.- 1.5.2. Selectivity.- 1.6. Stationary Phases.- References.- Two: Glass WCOT Columns.- 2.1. Glass Surfaces as Support Materials.- 2.1.1. Fused Silica.- 2.1.2. Soft Glasses.- 2.1.3. Borosilicate Glass.- 2.2. Glass Surface Properties.- 2.3. Dehydration and Rehydration of Glass Surfaces.- 2.4. Capillary Tubing Fabrication.- 2.5. WCOT Column Surface Modifications.- 2.5.1. General Considerations.- 2.5.2. Surface-Roughening Techniques.- 2.5.3. HCl-Induced Crystallization in Gaseous Phase.- 2.5.4. Pyrex Glass Surface Modification.- 2.5.5. Deposition of Barium Carbonate.- 2.5.6. Other Roughening Methods.- 2.6. Glass Surface Deactivation and Chemical Modification.- 2.7. Coating the WCOT Column.- 2.7.1. Dynamic Methods.- 2.7.2. Static Techniques.- 2.8. WCOT Column Conditioning.- 2.9. Glass WCOT Column Maintenance.- References.- Three: Inlet Systems.- 3.1. General Considerations.- 3.2. Sample Introduction Techniques.- 3.2.1. Cold Syringe Needle Injection.- 3.2.2. Filled Syringe Needle Injection.- 3.2.3. Air Plug Method.- 3.2.4. Hot Syringe Needle Injection.- 3.2.5. Solvent Flush Technique.- 3.3. Split Sampling Technique.- 3.4. Splitless Sampling Technique.- 3.5. On-Column Injection Techniques.- 3.6. Direct Injection.- 3.7. Column-Switching Techniques.- 3.7.1. Splitless Injection.- 3.7.2. The Back-Flushing Method.- 3.7.3. Preseparation with Packed-Column and Intermediate-Peak Trapping.- 3.7.4. Preseparation with Packed-Column, Dual Injection, and Intermediate-Peak Trapping.- 3.8. Flow Programming in WCOT Column Gas Chromatography.- References.- Four: Detectors.- 4.1. Flame Ionization Detector.- 4.1.1. Optimization of the FID.- 4.1.2. Detector Maintenance.- 4.2. Electron Capture Detector.- 4.2.1. Principles and Operation of the ECD.- 4.2.2. Contamination of the ECD.- 4.2.3. Response Factors.- 4.2.4. Troubleshooting Electron Capture Detectors.- 4.2.5. Cleaning Electron Capture Detectors.- 4.3. Thermionic (Alkali Flame Ionization) Detector.- 4.3.1. Mechanism of Selectivity of a TED Detector.- 4.3.2. Phosphorus Mode.- 4.3.3. Selectivity and Response of TED.- 4.4. Photoionization Detector.- 4.5. The Mass Spectrometer as Detector.- 4.5.1. The Mass Spectrometer.- 4.5.2. Requirements for an Optimal GC/MS Combination.- 4.5.3. Requirements for the Mass Spectrometer.- 4.5.4. Vacuum Technology.- 4.5.5. Ion Source Optics.- 4.5.6. Scanning Time.- 4.5.7. Repetitive Scan.- 4.5.8. Selected Ion Monitoring.- 4.5.9. Computer Compatibility.- 4.6. Operational Modes of an Ion Source.- 4.6.1. Electron Impact Ionization.- 4.6.2. Chemical Ionization.- 4.6.3. Field Ionization.- 4.6.4. Field Desorption.- 4.6.5. Atmospheric Pressure Ionization.- 4.6.6. Tandem Mass Spectrometry (MS/MS) and GC/MS/MS.- 4.7. GC/MS Interface.- 4.7.1. Open Split.- 4.7.2. Direct Coupling.- 4.8. Parameters Affecting Performance of GC/MS System.- References.- Five: Sample Preparation.- 5.1. General Considerations.- 5.2. Planning the Analytical Study.- 5.2.1. Sampling.- 5.2.2. Extraction Procedures.- 5.3. Cleanup Procedures.- 5.3.1. Solvents and Reagent Purity.- 5.3.2. Quality of Adsorbents.- 5.3.3. Group Selective Adsorbents.- 5.3.4. Open-Pore Polyurethane.- 5.4. Liquid-Liquid Extraction.- 5.5. Liquid Chromatography.- 5.6. Headspace Analysis.- 5.6.1. Closed-Loop Stripping Techniques.- 5.6.2. Preconcentration of Contaminants Using Automatic Purge and Trap Devices.- 5.7. Thermal Desorption Methods.- 5.8. Steam Distillation.- 5.9. Partitioning Methods.- 5.10. Miscellaneous Methods.- 5.11. Air Sampling.- 5.12. Source Sampling Procedures.- References.- Six: The Retention Index System.- 6.1. Introduction.- 6.2. Kovats Retention Index System.- 6.2.1. Calculation and Precision.- 6.2.2. Effects of Temperature.- 6.3. Compound Identification by Retention Index.- 6.4. Other Retention Systems.- References.- Seven: Quantitative Analysis.- 7.1. General Considerations.- 7.1.1. Peak Height Measurements.- 7.1.2. Peak Area Measurements.- 7.1.3. Digital Integrators.- 7.1.4. Microcomputers.- 7.2. Principles of Quantitative Analysis.- 7.2.1. Normalization.- 7.2.2. External Standardization.- 7.2.3. Internal Standardization.- 7.2.4. Standard Addition.- 7.3. Statistical Considerations.- 7.3.1. Mean Value.- 7.3.2. Standard Deviation.- 7.3.3. Precision and Accuracy.- 7.3.4. Establishing Control Limits.- 7.4. Primary Standards in Air Pollution Analysis.- References.- Eight: Application in Environmental Analysis.- 8.1. Introduction.- 8.2. Analysis of Organic Priority Pollutants in Water.- 8.2.1. Nonvolatile Pollutants.- 8.2.2. Base-Neutral Extraction.- 8.2.3. Acid-Extractable Priority Pollutants.- 8.2.4. Pesticides.- 8.3. Determination of Groups of Compounds.- 8.4. Polycyclic Aromatic Hydrocarbons.- 8.4.1. General Considerations.- 8.4.2. Sampling Requirements.- 8.4.3. High-Resolution WCOT Column Gas Chromatography.- 8.4.4. Detection Systems.- 8.4.5. Quantitative Analysis.- 8.4.6. Qualitative Analysis.- 8.5. Heterocyclic Aromatic Hydrocarbons.- 8.5.1. Nitrogen-Containing PAH (Azaarenes).- 8.5.2. Polycyclic Aromatic Amines (PAA).- 8.5.3. Nitro Polycyclic Aromatic Hydrocarbons.- 8.5.4. Sulfur-containing Polycyclic Aromatic Hydrocarbons.- 8.6. Halogenated Aliphatic Hydrocarbons.- 8.6.1. Halogenated Alkanes and Alkenes.- 8.6.2. Chlorinated Dimethanonaphthalenes and Methanoindene Pesticides.- 8.6.3. Analysis for Mirex and Kepone.- 8.7. Halogenated Aromatic Hydrocarbons.- 8.7.1. Chlorinated Benzenes.- 8.7.2. Polychlorinated and Polybrominated Biphenyls and Terphenyls.- 8.7.3. Polybrominated Biphenyls.- 8.7.4. Polychlorinated Terphenyls.- 8.8. Polychlorinated Dibenzo-1,4-Dioxins.- 8.8.1. Sample Preparation.- 8.8.2. Qualitative PCDD Analysis.- 8.8.3. Quantitative PCDD Analysis.- 8.8.4. Application of WCOT Columns in PCDD Analysis.- 8.9. Chlorinated Dibenzofurans.- 8.10. Chlorinated Phenols and Related Compounds.- 8.10.1. Sample Preparation.- 8.10.2. Extraction and Cleanup Procedures.- 8.10.3. Derivatization of Phenols.- 8.10.4. Qualitative and Quantitative Applications of WCOT Columns.- 8.11. Toxaphene.- 8.11.1. Sample Preparation and Cleanup.- 8.11.2. WCOT Column Gas Chromatography for Toxaphene.- 8.11.3. Quantitative Analysis of Toxaphene.- 8.11.4. Toxaphene Analysis.- 8.12. Phthalate Esters.- 8.12.1. Qualitative Analysis.- 8.12.2. Sample Preparation and Cleanup.- 8.13. Nitrosamines.- 8.13.1. Detection Systems.- 8.13.2. Applications.- 8.14. Nonionic Detergents.- 8.14.1. Extraction Procedures.- 8.14.2. Qualitative and Quantitative Analysis.- 8.15. Miscellaneous Separations.- 8.15.1. Separation of s-Triazines and Substituted Urea Herbicides.- 8.15.2. Volatile Chelates of Metal Ions.- 8.15.3. Odorous Compounds in Water, Fish, and Food.- 8.15.4. Fatty Acids.- References.