x Contents 3 The Stationary Phase in Thin-Layer Chromatography Activating and Deactivating Stationary Phases Snyder s Adsorption M

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1 Contents 1 History of Planar Chromatography History of Paper Chromatography (PC) History of Thin-Layer Chromatography The History of Quantitative Planar Chromatography... 8 References Theoretical Basis of Thin Layer Chromatography (TLC) Planar and Column Chromatography TLC Capillary Flow TLC Distribution Equilibrium Adsorption Chromatography Partition Chromatography The Retardation Factor (R f ) The Empirical R f Factor The Thermodynamic R 0 f Factor Mobile Phase Composition Transfer of TLC Separations to Columns The R m Value Temperature Dependence of TLC Separations Advanced Theoretical Considerations Indices Characterizing Separation and Resolution Zone Broadening in Planar Chromatography The A term The B term The C term Local Plate Height H The van Deemter Equation Optimum Separation Conditions in TLC Separation Number Real Plate Height References ix

2 x Contents 3 The Stationary Phase in Thin-Layer Chromatography Activating and Deactivating Stationary Phases Snyder s Adsorption Model Layer Characteristics Layer Thickness (d f ) Average Particle Size (d p ) Particle Size Distribution Specific Surface Area (O s ) Pore Volume (V p ) Average Pore diameter (P d ) The Most Important Stationary Phases in TLC Aluminium Oxide Magnesium Silicate Silica Gel Chemically Bonded Silica Gel Layers Kieselguhr Cellulose Polyamides Ion Exchange Resins Chiral Phases Layers with Fluorescent Indicators Making Your Own Plates Light Absorption on Plate Surfaces References The Mobile Phase in Adsorption and Partition Chromatography Solvent Characteristics Solvent Theory for Adsorption Chromatography (According to Snyder) Solvent Strength (e 0 ) Solvent Strength of Binary Mixtures Solvent Theory in Partition Chromatography Solvent Theory (According to Snyder) Other Methods for Characterizing Solvents Optimizing Solvent Composition The PRISMA Model (According to Nyiredy) Solvent Additives Appendix: Solvent Properties References Preparing and Applying Samples Sample Preparation The QuEChERS Approach Solid-Phase Extraction Stir Bar Sorptive Extraction

3 Contents xi 5.2 The Dosage Quality Choice of Application Position Practical Application Methods Sample Application via Plate Contact Sample Application Without Plate Contact Sample Application via Contact Spotting Plate Overloading and Incomplete Drying References Basis for TLC Development Techniques Influence of the Vapour Phase Chamber Types for Linear Development N-Chambers ( Trough Chambers ) S-Chamber ( Small Chamber ) Vario-KS-Chamber The H-Chamber ( Horizontal Chamber ) Controlling Separations via the Vapour Phase Solvent Composition During Separation Plate Pre-loading via the Vapour Phase Circular Separations Solvent Gradients Theory of Solvent Gradients Evaporation-Controlled Gradient Elution Multiple Development in TLC Automated Multiple Development (AMD) Normal Phase Separations with Water-Containing Solvents Plate Development with Forced Flow Rotation Planar Chromatography (RPC) Over-pressure Layer Chromatography (OPLC) Two Dimensional TLC (2D TLC) Development in Orthogonal Directions Grafted TLC Stability Test and SRS Technique Drying the Plate References Specific Staining Reactions Chemical Reactions Prior to Separation (Pre-chromatographic Derivatization) Sample Enrichment by Pre-chromatographic Derivatization Pre-chromatographic In Situ Derivatization Pre-chromatographic Staining Reagents in the Mobile Phase

4 xii Contents 7.2 Post-chromatographic Reactions (Derivatization After Development) Fluorescence Enhancer ph and Redox Indicators Universal Reagents (Charring Reagents) Aldehyde Reagents CH- and NH-Reacting Reagents Boron-Containing Reagents Alkaline Reagents Chloramine-T Reagent Diazotization Reactions Iodine-Starch and Wursters Reagents Reactions with Metal Reagents Reagents for Metal Cations Reactions via the Gas Phase Ammonium Bicarbonate Reagent Tin(IV) Chloride Reagent Formic Acid Reagent Hydrogen Chloride Reagent Trichloroacetic Acid Reagent Nitric Acid Reagent Thermal Treatment of TLC Plates Activity Analysis Using Chemical Reagents Folin Ciocalteu Reagent Checking for Free Radical Scavenger Activity Using DPPH Reagent Nucleophilic Reaction Ability References Bioeffective-Linked Analysis in Modern HPTLC Principle of the Method Contaminant Analysis in the Environment and Food and the Principle of Bioactivity-Based Analysis Aims and Fundamental Aspects of Bioeffective-Linked Analysis by Thin-Layer Chromatography HPTLC as a Method for Bioeffective-Linked Analysis General Rules for the Analysis of Bioeffective Compounds Enzyme Tests Urease-Inhibition Test for Heavy Metals Analysis Using Redox Enzymes The Detection of Cholinesterase Inhibitors Inhibition of Photosynthesis by Herbicides Reagent Preparation Hill Reaction Detection Using Algae

5 Contents xiii 8.5 Detecting Bioeffective Compounds with Photobacteria Practical Use of Photobacteria Reaction Time Optimization Applications of Photobacteria Detection of Fungicidal- and Antibiotical-Active Substances in Environmental Samples Determining Fungicides Screening of Pesticides in Food and Surface Water Detection of Compounds by Antibiotic Activity Yeast Estrogen Screen References Planar Chromatography Detectors Transmittance Measurements in Thin-Layer Chromatography The Lambert-Beer Law Reflectance Measurements in TLC and HPTLC The Kubelka Munk Equation Reflectance Measurements with a Diode-Array Scanner Spatial Resolution on the Plate Spectral Distribution on HPTLC Plates Spectral Evaluation Algorithm Video-Densitometric Measurements Infrared and Raman Detection in Thin-Layer Chromatography Analysis of Thin-Layer Chromatograms by Diffuse Reflectance Infrared Fourier Transformation Analysis of Thin-Layer Chromatograms by Near-Infrared FT-Raman Spectroscopy Analysis of Thin-Layer Chromatograms by Surface-Enhanced Raman Scattering Spectrometry Mass Spectrometric Detection in TLC Direct Plate Extraction (SSSP) MALDI Techniques (MALDI-MS) Atmospheric Pressure Mass Spectrometry Thin-Layer Radiochromatography (TL-RC) Direct Radioactivity Measurements on TLC Plates Phosphor Imaging References Diffuse Reflectance from TLC Layers The Lambert Cosine Law Theory of Diffuse Reflectance Special Case a: The Reversal Reflectance Formula Special Case b: The Fluorescence Formula Special Case c: The Kubelka Munk Expression

6 xiv Contents 10.3 Mass-Dependent Reflection Simplifying the Expression References Fluorescence in TLC Layers Theory of Fluorescence and Phosphorescence Fluorescence Enhancement Quantification in TLC by Fluorescence Low Sample Concentration Fluorescence in Light Scattering Media High Sample Concentration Fluorescence in Light Scattering Media Contour Plots for Fluorescence Evaluation TLC Plates Containing a Fluorescent Dye References Chemometrics in HPTLC Calculation of R F Values Compound Identification Using UV Visible and Fluorescence Spectra Correlation Spectroscopy Theory of Correlation Spectroscopy Combination of R F and UV Visible Spectral Library Search Zone Purity Check Selection of the Measurement Wavelength Statistical Photometric Error (Detector Variance) Reciprocal Model Absorbance Model Kubelka Munk Model Fluorescence model Minimizing the Statistical Photometric Error Diode Bundling and Data Smoothing Signal Integration: Area or Height Evaluation? Deconvolution of Overlapping Peaks New Visualization Methods for Plots References Statistics for Quantitative TLC The Mean Value Variance and Precision Definition of Variance Relative Variance Quantification of Relative Variance

7 Contents xv 13.3 Trueness, Precision, and Accuracy The Gauss Distribution Area of the Gauss Distribution Quantiles of the Gauss Distribution Test for a Normal Distribution Student s Distribution (t Distribution) Error Propagation Calibration Methods The Linear Calibration Function Estimating X C Estimating a and Y C Estimating the variances of a and Y C The F-Test The Linear Regression Variance The Analytical Function of Linear Regression Quantitative Analysis Using External Standards Second-Order Calibration Function Analytical Function of the Second-Order Calibration Risk of Systematic Error Constant Systematic Error Proportional Systematic Error Use of Internal Standards Standard Addition Method Mean t Test References Planning an Analysis and Validation in TLC Terms Used in Validation Method Validation Testing Specificity Quantifying Analytes General Aspects of Calibration Linearity and Working Range Choosing a Calibration Function External Standard Calculation Optimized Calibration Methods Precision Accuracy Confidence Interval Limit of Detection and Limit of Quantification Robustness Control Charts as Quality Indicators in Routine Analysis References Index

Introduction to Pharmaceutical Chemical Analysis

Introduction to Pharmaceutical Chemical Analysis Hansen, Steen ISBN-13: 9780470661222 Table of Contents Preface xv 1 Introduction to Pharmaceutical Analysis 1 1.1 Applications and Definitions 1 1.2 The