Meyer Pitfalls and Errors of HPLC in Pictures

3rd Revised and Enlarged Auflage
ISBN: 978-3-527-65912-8
Verlag: Wiley-VCH
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 210 Seiten, E-Book

The third edition of this popular problem-solving guide for this widely-used method includes eleven completely new examples and several updated ones, adding up to 100 contributions about pitfalls and errors in HPLC. Each example is presented on a double page with the text on the left-hand and a fi gure on the right-hand side, true to the motto 'a picture says more than a thousand words'. In addition, the author presents essential fundamentals as well as helpful strategies, such as equipment tests or quality assurance processes.   New in this edition   * Variability of the standard deviation * Infl uence of the acid type and concentration in the eluent * Water as an unintentional additive in the mobile phase * Inadequate purity of mobile phase water * Incomplete degassing * Inadequate stabilization of the extraction solvent * Tailing of phosphate compounds in the presence of steel * Different detection properties of diastereomers * Detector overload in ELSD * System suitability test * From repeatability to reproducibility   A must-have resource for all users - showing how to use HPLC efficiently and obtain reliable results.

Autoren/Hrsg.

Meyer, Veronika R.

Inhaltsverzeichnis

PREFACE   INTRODUCTION   PART I: Fundamentals Chromatography Chromatographic Figures of Merit The Resolution of Two Peaks Reduced Parameters The Van Deemter Curve Peak Capacity and Number of Possible Peaks Statistical Resolution Probability: Simulation Statistical Resolution Probability: Example Precision and Accuracy of an Analytical Result Standard Deviation Variability of the Standard Deviation Uncertainty Propagation Reproducibility in Trace Analysis Ruggedness Calibration Curves The HPLC Instrument The Detector Response Curve Noise The Playground Presented as an Ishikawa Diagram The Possible and the Impossible   PART II: Pitfalls and Sources of Error Mixing of the Mobile Phase Mobile Phase pH Adjustment of Mobile Phase pH Influence of the Acid Type and Concentration in the Eluent Water as an Unintentional Additive in the Mobile Phase Inadequate Purity of Mobile Phase Water Inadequate Purity of a Mobile Phase Solvent Inadequate Purity of a Mobile Phase Reagent Incomplete Degassing System Peaks and Quantitative Analysis Sample Preparation with Solid Phase Extraction Inadequate Stabilization of the Extraction Solvent Poor Choice of Sample Solvent: Peak Distortion Poor Choice of Sample Solvent: Tailing Sample Solvent and Calibration Curve Impurities in the Sample Formation of a By-Product in the Sample Solution Decomposition by the Sample Vial Artifact Peaks from the Vial Septum Formation of an Associate in the Sample Solution Precision and Accuracy with Loop Injection Injection Technique Injection of Air Sample Adsorption in the Loop Extra-Column Volumes Dwell Volume Elution at t0 Classification of C18 Reversed Phases Different Selectivity of C18 Reversed Phases Different Batches of Stationary Phase Chemical Reaction within the Column Tailing of Phosphate Compounds in the Presence of Steel Recovery and Peak Shape Problems with Proteins Double Peaks from Stable Conformers Influence of Temperature on the Separation Thermal Non-Equilibrium within the Column Influence of the Flow Rate on the Separation Influence of Run Time and Flow Rate on Gradient Separations UV Spectra and Quantitative Analysis UV Detection Wavelength Different Detection Properties of Diastereomers Fluorescence Quenching by Air Detector Overload in UV Detector Overload in ELSD Influence of the Retention Factor on Peak Height Influence of the Flow Rate on Peak Area Leaks in the HPLC Instrument Impairment of Precision as a Result of Noise Determination of Peak Area and Height at High Noise Peak Height Ratios Incompletely Resolved Peaks Area Rules for Incompletely Resolved Peaks Areas of a 1 : 10 Peak Pair Heights of a 1 : 10 Peak Pair Quantitative Analysis of a Small Peak Incompletely Resolved Peaks with Tailing Integration Threshold and Number of Detected Peaks Detector Time Constant and Peak Shape Quantitative Analysis in the 99% Range Correlation Coefficient of Calibration Curves   PART III: Useful Strategies Column Tests Apparatus Tests Wavelength Accuracy of the UV Detector Internal Standards A Linearity Test Rules for Accurate Quantitative Peak Size Determination High-Low Chromatography Control Charts Verification of the Analytical Result by Use of a Second Method Description of Ruggedness Rules for Passing On an HPLC Method Quality Assurance in the Laboratory Standard Operating Procedures Method Validation Some Elements of Validation A Validation Example System Suitability Test From Repeatability to Reproducibility Measurement Uncertainty Formal Quality Assurance Systems   INDEX

Über Autor(innen)

Following an apprenticeship as laboratory assistant, Veronika R. Meyer studied chemistry at the University of Applied Sciences in Burgdorf (Switzerland). From 1976 to 1998 she worked with HPLC at Berne University, where she also completed her PhD thesis in Chemistry. Afterwards she spent her post-doc time at the Weizmann-Institute in Rehovot (Israel) and at the University of Delaware, Newark, DE. Since 1998 she is working for EMPA (Swiss Federal Laboratories for Materials Science and Technology) in St. Gallen. The first German edition of her textbook 'Practical High-Performance Liquid Chromatography' was published in 1979. Veronika R. Meyer is author of numerous papers in international journals and teaches at Berne University.