Pitfalls and Errors of HPLC in Pictures -- Contents -- Preface -- Introduction -- Part I Fundamentals -- 1.1 Chromatography -- 1.2 Chromatographic Figures of Merit -- 1.3 The Resolution of Two Peaks -- 1.4 Reduced Parameters -- 1.5 The Van Deemter Curve -- 1.6 Peak Capacity and Number of Possible Peaks -- 1.7 Statistical Resolution Probability: Simulation -- 1.8 Statistical Resolution Probability: Example -- 1.9 Precision and Accuracy of an Analytical Result -- 1.10 Standard Deviation -- 1.11 Variability of the Standard Deviation -- 1.12 Uncertainty Propagation -- 1.13 Reproducibility in Trace Analysis -- 1.14 Ruggedness -- 1.15 Calibration Curves -- 1.16 The HPLC Instrument -- 1.17 The Detector Response Curve -- 1.18 Noise -- 1.19 The Playground Presented as an Ishikawa Diagram -- 1.20 The Possible and the Impossible -- Part II Pitfalls and Sources of Error -- 2.1 Mixing of the Mobile Phase -- 2.2 Mobile Phase pH -- 2.3 Adjustment of Mobile Phase pH -- 2.4 Influence of the Acid Type and Concentration in the Eluent -- 2.5 Water as an Unintentional Additive in the Mobile Phase -- 2.6 Inadequate Purity of Mobile Phase Water -- 2.7 Inadequate Purity of a Mobile Phase Solvent -- 2.8 Inadequate Purity of a Mobile Phase Reagent -- 2.9 Incomplete Degassing -- 2.10 System Peaks and Quantitative Analysis -- 2.11 Sample Preparation with Solid Phase Extraction -- 2.12 Inadequate Stabilization of the Extraction Solvent -- 2.13 Poor Choice of Sample Solvent: Peak Distortion -- 2.14 Poor Choice of Sample Solvent: Tailing -- 2.15 Sample Solvent and Calibration Curve -- 2.16 Impurities in the Sample -- 2.17 Formation of a By-Product in the Sample Solution -- 2.18 Decomposition by the Sample Vial -- 2.19 Artifact Peaks from the Vial Septum -- 2.20 Formation of an Associate in the Sample Solution -- 2.21 Precision and Accuracy with Loop Injection.

2.22 Injection Technique -- 2.23 Injection of Air -- 2.24 Sample Adsorption in the Loop -- 2.25 Extra-Column Volumes -- 2.26 Dwell Volume -- 2.27 Elution at t0 -- 2.28 Classification of C18 Reversed Phases -- 2.29 Different Selectivity of C18 Reversed Phases -- 2.30 Different Batches of Stationary Phase -- 2.31 Chemical Reaction within the Column -- 2.32 Tailing of Phosphate Compounds in the Presence of Steel -- 2.33 Recovery and Peak Shape Problems with Proteins -- 2.34 Double Peaks from Stable Conformers -- 2.35 Influence of Temperature on the Separation -- 2.36 Thermal Non-Equilibrium within the Column -- 2.37 Influence of the Flow Rate on the Separation -- 2.38 Influence of Run Time and Flow Rate on Gradient Separations -- 2.39 UV Spectra and Quantitative Analysis -- 2.40 UV Detection Wavelength -- 2.41 Different Detection Properties of Diastereomers -- 2.42 Fluorescence Quenching by Air -- 2.43 Detector Overload in UV -- 2.44 Detector Overload in ELSD -- 2.45 Influence of the Retention Factor on Peak Height -- 2.46 Influence of the Flow Rate on Peak Area -- 2.47 Leaks in the HPLC Instrument -- 2.48 Impairment of Precision as a Result of Noise -- 2.49 Determination of Peak Area and Height at High Noise -- 2.50 Peak Height Ratios -- 2.51 Incompletely Resolved Peaks -- 2.52 Area Rules for Incompletely Resolved Peaks -- 2.53 Areas of a 1 : 10 Peak Pair -- 2.54 Heights of a 1 : 10 Peak Pair -- 2.55 Quantitative Analysis of a Small Peak -- 2.56 Incompletely Resolved Peaks with Tailing -- 2.57 Integration Threshold and Number of Detected Peaks -- 2.58 Detector Time Constant and Peak Shape -- 2.59 Quantitative Analysis in the 99% Range -- 2.60 Correlation Coefficient of Calibration Curves -- Part III Useful Strategies -- 3.1 Column Tests -- 3.2 Apparatus Tests -- 3.3 Wavelength Accuracy of the UV Detector -- 3.4 Internal Standards.

3.5 A Linearity Test -- 3.6 Rules for Accurate Quantitative Peak Size Determination -- 3.7 High-Low Chromatography -- 3.8 Control Charts -- 3.9 Verification of the Analytical Result by Use of a Second Method -- 3.10 Description of Ruggedness -- 3.11 Rules for Passing On an HPLC Method -- 3.12 Quality Assurance in the Laboratory -- 3.13 Standard Operating Procedures -- 3.14 Method Validation -- 3.15 Some Elements of Validation -- 3.16 A Validation Example -- 3.17 System Suitability Test -- 3.18 From Repeatability to Reproducibility -- 3.19 Measurement Uncertainty -- 3.20 Formal Quality Assurance Systems -- Index.