UV-Visible Spectrophotometry of Water and Wastewater

Olivier Thomas, Christopher Burgess

• Publisher: Elsevier Science
• Year: 2017
• ISBN:
  9780444639004
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Environmental Management
• Index: Technology & Engineering

UV-Visible Spectrophotometry of Water and Wastewater, Second Edition, represents an update to the first book dedicated to the use of UV spectrophotometry for water and wastewater quality monitoring. Using practical examples, the book illustrates how this technique can be a source of new methods of characterization and measurement.

Easy and fast to run, this simple and robust analytical technique must be considered as one of the best ways to obtain a quantitative estimation of specific or aggregate parameters (e.g., Nitrate, TOC) and simultaneously qualitative information on the global composition of water and its variation.

This second edition presents the current methods and applications for water quality monitoring based on UV spectra, including the most recent works and developments. After the introduction of the basics for UV spectrophotometry understanding, the applications of UV measurement are presented, both from the family of chemicals and water quality parameters and from the type of water.

Writing from years of experience in the development and applications of UV systems and from scientific and technical works, the authors provide several useful examples showing the great interest of UV spectrophotometry for water quality monitoring. At the end of the book, the UV spectra library of the first edition is updated with dozens of new chemicals of interest.

• Adds dozens of new chemicals of interest to the first library of UV-spectra dedicated to water, providing data readily available for researchers and users
• Includes new sections on data integrity and security, UV estimation of classes of compounds, UV and turbidity, drinking water, pollution tracking, high frequency monitoring, disinfection by products assessment, pesticides, pharmaceuticals, and more
• Provides a theoretical basis for further research in the field of spectra exploitation
• Contains helpful practical applications of this quick, simple, and inexpensive technique

Chapter 1

The Basis for Good Spectrophotometric UV–Visible Measurements

Christopher Burgess, Burgess Analytical Consultancy Limited, Durham, United Kingdom

Abstract

In order to apply UV–visible spectrophotometric techniques for water and wastewater analyses correctly and reliably, an understanding of the principles behind the technique is needed as well as guidance in best operational laboratory practices in order to obtain reliable spectral data.

The chapter covers the basics of the interaction of light with solutions containing chromophores and other absorbing and scattering processes. The calibration requirements for assuring adequate accuracy and precision of the spectrophotometer to produce reliable spectral data are discussed. The role of certified reference standards is given with recommended procedure and examples.

Sample presentation and sample management are also critical elements in this process. Factors which may affect the spectral characteristics are outlined and data treatment techniques are introduced which will be further explored in other chapters. The importance of data integrity and security is emphasised in the context of regulated requirements such as ISO Guide 17025.

Keywords

Good spectroscopic practice; UV–visible spectrophotometry; instrument calibration; reference standards; chromophore; spectrophotometer; absorbance accuracy; wavelength accuracy; stray light; spectral bandwidth; Beer–Lambert law; spectral characteristics; data integrity; solvent quality; cuvette; ISO Guide 17025

Contents

1.1 Introduction 2

1.2 Interaction of Light With Matter 2

1.2.1 The Electromagnetic Spectrum 2

1.2.2 The Origin of Spectra, Absorption of Radiation by Atoms, Ions and Molecules 4

1.2.3 Quantitative Laws of the Attenuation of Light 8

1.2.4 Presentation of Spectral Data 10

1.2.5 Nomenclature 12

1.3 Factors Affecting the Quality of Spectral Data 12

1.3.1 Good Spectroscopic Practice 12

1.3.2 Instrumental Performance Criteria 13

1.3.3 Use of Certified Reference Materials 14

1.3.4 Procedures and Best Practices for Assuring Spectrophotometer Performance 15

1.4 Sample Presentation 26

1.4.1 Cuvettes 26

1.4.2 Cleaning Procedures 28

1.5 Factors Influencing Spectral Characteristics 28

1.5.1 Sample Handing and Storage 28

1.5.2 Turbidity 28

1.5.3 Solvent Quality and Polarity 29

1.5.4 pH 29

1.5.5 Ionic Strength 29

1.5.6 Temperature 30

1.5.7 Data Treatment 30

1.6 Data Integrity and Security 32

References 34

Further Reading 35

1.1 Introduction

This book is concerned with the application of UV–visible spectrophotometry to the identification and determination of materials in a variety of water samples. The spectra included in this book form a resource that enables users to apply the technique to their own samples. However, in order to apply UV–visible spectrophotometry data and information properly and reliably, we need to have an understanding of the principles and practices upon which it is based. The purpose of this chapter is to cover the essential elements. The reader who wishes to explore the subject further may turn to the more detailed and specialised works referenced in the bibliography.

1.2 Interaction of Light With Matter

1.2.1 The Electromagnetic Spectrum

Spectroscopic processes rely on the fact that electromagnetic radiation (EMR) interacts with atoms and molecules in discrete ways to produce characteristic absorption or emission profiles. This is examined in more detail in Section 1.2.2. Before we can consider the origin of spectra, we have to look at some of the properties of EMR.

Our own ability to perceive colour is owing to the human eye acting as a detector for EMR. The property of EMR that determines the range of colour perceived is wavelength. The part of the electromagnetic spectrum that the eye can detect is known, unsurprisingly, as the visible region. EMR may be simply represented as a sine wave. Wavelength, λ, is the distance between adjacent peaks or troughs. This is illustrated in Fig. 1.1.

Figure 1.1 Sine wave r...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Preface to the Second Edition
• Chapter 1. The Basis for Good Spectrophotometric UV–Visible Measurements
• Chapter 2. From Spectra to Qualitative and Quantitative Results
• Chapter 3. Organic Constituents
• Chapter 4. Aggregate Organic Constituents
• Chapter 5. Mineral Constituents
• Chapter 6. Physical and Aggregate Properties
• Chapter 7. Natural Water
• Chapter 8. Drinking Water
• Chapter 9. Urban Wastewater
• Chapter 10. Industrial Wastewater
• Chapter 11. Leachates and Organic Extracts From Solids
• Chapter 12. UV Spectra Library
• Index