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Analytical chemistry of foods
Book Reviews
The growth in studies of nonlinear optical effects in recent years can be attributed to the application of lasers to molecular spectroscopy. The high intensity and monochromaticity of these light sources make possible the detection of second, third and high order effects. It is the aim of the author of this text to relate these effects to each other. To do this the author takes the reader through general aspects of elastic scattering of radiation by matter (Chapter 2). In this important introductory chapter Ward graphs and ladder graphs are introduced as convenient pictorial representations of nonlinear phenomena. This approach enables the reader to understand subsequent chapters without necessary recourse to mathematical descriptions of these phenomena. Detailed mathematical derivations are included in a series of appendices which amplify the subject matter in each chapter. I liked this form of presentation as it makes the text less formidable for practical spectroscopists yet provides all the information required by serious theoretically minded students or newcomers to this field of spectroscopy. In subsequent chapters particular optical phenomena are considered. Chapter 3 deals with linear and non linear elastic scattering including Rayleigh scattering, refraction and dispersion, CD scattering and optical rotatory dispersion (first order effects) and scan and difference frequency generation (second order effects). Third harmonic generation is also considered here using the same graphical representation to describe degenerate four-wave mixing and coherent antistokes Raman scattering. Scattering and refraction in static fields covers a range of better know phenomena such as the linear electro-optical effect (Pockels effect), the electric Kerr effect, the Faraday effect, the magneto-optical Kerr effect and magneto-chiral birefringence. These effects are described in brief in a very limited fashion: brief to the point of serving only to justify the use of graphs to represent the phenomena rather to explain the phenomena. This is a criticism which also applies to some of the more esoteric techniques included, e.g., degenerate four-wave mixing as discussed in the previous chapter. It would have been helpful to have a brief description of experimental details of how these effects are induced. In effect by omitting such details the author has
407
limited the book’s appeal to those who are familiar with the subject material. This is a pity since a book which rationalises these effects would be very useful to the wider audience of practical spectroscopists and undergraduate students. The same criticism can be directed at the remaining chapters which deal very briefly indeed with optical rectification, the inverse Faraday effect and absorption and emission of radiation, inelastic scattering and the Raman effect. In all the written text is covered in 78 pages. The appendices then occupy a further 104 pages so the book is also to be judged on these. For the beginner the appendices are quite daunting, requiring a very good recall of undergraduate physics and mathematics. For the researcher working in this field they represent an excellent handbook of the necessary derivations required to explain the phenomena represented in earlier chapters. It is the inclusion of these detailed appendices that confirms that the book is aimed at postgraduate and postdoctoral researchers in the field not the general audience of spectroscopists working in analytical chemistry. If you fall into the former category this is really a very useful book. R.D. Snook
Ceirwyn S. James, Analytical Chemistry of Foods, Blackie, Glasgow, 1995 (ISBN 0-7514-0196-X). 178 pp. Price f15.99. This book is primarily intended for use by students of food science and technology and describes a range of analytical methodologies for the main food constituents. The book is well written and easy to follow. I was pleased to see that the second chapter, following the introduction, dealt with an assessment of errors in analytical chemistry and the quality of data. This is a topic that tends to be neglected yet is of fundamental importance. Chapter three provided a concise overview of the principles of the techniques used in food analysis. The descriptions were very clear and although easily understood were perhaps a little too basic, particularly since very few references were given to direct the interested reader to more detailed texts. Spectroscopic methods were given very limited coverage which is a pity since these are of increasing importance in the food industry. Chap-
408
Book Reviews
ter four described the theory of analytical methods for specific food constituents, chapter five provided detailed experimental procedures for the estimation of major food constituents and chapter six gave examples of more general food studies. These last three chapters constitute the experimental section of the book which is clearly the most important, providing students and others with clear instructions for performing all of the standard determinations. This section is very useful, serving as a reference work and handbook, although no literature is cited. However, chapter seven does provide a limited list of alternative reading material. In conclusion I thought this book, despite some omissions, is overall a good guide to “conventional” food analytical techniques and extremely good value at the price. R.H. Wilson
Keith B. Oldham and C. Myland, Fundamentals of Electrochemical Science, Academic Press, San Diego, CA, 1994 (ISBN O-12-525545-4). xxii + 474 PP. This book aims to cover the fundamentals of electrochemical science and does so in a fairly comprehensive manner. The authors, however, admit that the subject is very broad and certain important areas such as modified electrodes and semi-conductor electrodes are not covered because of their lack of expertise in the area. The book is not aimed at a particular audience but is in more depth than would be required for those who just want a simple introduction or overview. The mathematics will put off the faint hearted and most undergraduates, but the book would be a good starting point for more advanced levels of study where a good understanding of electrochemical principles is required. The recommendation of a book on electrochemistry often depends on the sign convention used. The terms working and reference electrode are used where ever possible by the authors and the use of positive and negative electrodes is avoided. The anodic current at the working electrode is treated as positive and the increasingly positive electrode is plotted to the right in this book.
The book starts with two revision chapters on electricity and ionic solutions. It then goes on to cover electrochemical cells, electrodes, electrode reactions and polarisation as separate chapters. This is followed by a chapter on transport and then steady state voltammetry, the electrode interface, the use of periodic signals and transient voltammetry are covered. A bibliography of reviews is provided plus a glossary, physical constants, etc. The book is written from an electrochemical point of view and therefore does not discuss analytical aspects of electrochemistry in any detail, however, it would certainly be useful for an electroanalytical chemist who wished to understand electrochemical processes in more depth. The book uses clear examples and simple illustrations to convey ideas. Problems are used to help place equations in context. In general this is a clearly written book on electrochemistry which will be of use to anybody wishing to understand the subject in reasonable depth. G.M. Greenway
B.J. Alloway (Ed.)., Heavy Metals in Soils, 2nd edn., Blackie, Glasgow, 1995 (ISBN o-7514-0198-6). xiv + 368 pp. Price f75.00. This is a thoroughly revised version of the first edition that appeared in 1990 and is aimed primarily at environmental and soil scientists. There are fifteen international contributors and fourteen self contained and extensively referenced chapters. The early chapters consider the physical and chemical properties and sources of heavy metals in soils and the analytical techniques (including sampling and sample treatment) necessary for their determination. These are followed by ten chapters discussing individual elements including arsenic, cadmium, chromium, nickel, copper, lead, manganese, cobalt, mercury, selenium and zinc. The contents are very readable and full of useful quantitative information (particularly in the form of tables) relating to the distribution of heavy metals in soils, e.g., normal concentration ranges for heavy metals in soils and plants, which is often difficult to access. The presentation is of a consistently high quality and there is a good index and appendices.
The growth in studies of nonlinear optical effects in recent years can be attributed to the application of lasers to molecular spectroscopy. The high intensity and monochromaticity of these light sources make possible the detection of second, third and high order effects. It is the aim of the author of this text to relate these effects to each other. To do this the author takes the reader through general aspects of elastic scattering of radiation by matter (Chapter 2). In this important introductory chapter Ward graphs and ladder graphs are introduced as convenient pictorial representations of nonlinear phenomena. This approach enables the reader to understand subsequent chapters without necessary recourse to mathematical descriptions of these phenomena. Detailed mathematical derivations are included in a series of appendices which amplify the subject matter in each chapter. I liked this form of presentation as it makes the text less formidable for practical spectroscopists yet provides all the information required by serious theoretically minded students or newcomers to this field of spectroscopy. In subsequent chapters particular optical phenomena are considered. Chapter 3 deals with linear and non linear elastic scattering including Rayleigh scattering, refraction and dispersion, CD scattering and optical rotatory dispersion (first order effects) and scan and difference frequency generation (second order effects). Third harmonic generation is also considered here using the same graphical representation to describe degenerate four-wave mixing and coherent antistokes Raman scattering. Scattering and refraction in static fields covers a range of better know phenomena such as the linear electro-optical effect (Pockels effect), the electric Kerr effect, the Faraday effect, the magneto-optical Kerr effect and magneto-chiral birefringence. These effects are described in brief in a very limited fashion: brief to the point of serving only to justify the use of graphs to represent the phenomena rather to explain the phenomena. This is a criticism which also applies to some of the more esoteric techniques included, e.g., degenerate four-wave mixing as discussed in the previous chapter. It would have been helpful to have a brief description of experimental details of how these effects are induced. In effect by omitting such details the author has
407
limited the book’s appeal to those who are familiar with the subject material. This is a pity since a book which rationalises these effects would be very useful to the wider audience of practical spectroscopists and undergraduate students. The same criticism can be directed at the remaining chapters which deal very briefly indeed with optical rectification, the inverse Faraday effect and absorption and emission of radiation, inelastic scattering and the Raman effect. In all the written text is covered in 78 pages. The appendices then occupy a further 104 pages so the book is also to be judged on these. For the beginner the appendices are quite daunting, requiring a very good recall of undergraduate physics and mathematics. For the researcher working in this field they represent an excellent handbook of the necessary derivations required to explain the phenomena represented in earlier chapters. It is the inclusion of these detailed appendices that confirms that the book is aimed at postgraduate and postdoctoral researchers in the field not the general audience of spectroscopists working in analytical chemistry. If you fall into the former category this is really a very useful book. R.D. Snook
Ceirwyn S. James, Analytical Chemistry of Foods, Blackie, Glasgow, 1995 (ISBN 0-7514-0196-X). 178 pp. Price f15.99. This book is primarily intended for use by students of food science and technology and describes a range of analytical methodologies for the main food constituents. The book is well written and easy to follow. I was pleased to see that the second chapter, following the introduction, dealt with an assessment of errors in analytical chemistry and the quality of data. This is a topic that tends to be neglected yet is of fundamental importance. Chapter three provided a concise overview of the principles of the techniques used in food analysis. The descriptions were very clear and although easily understood were perhaps a little too basic, particularly since very few references were given to direct the interested reader to more detailed texts. Spectroscopic methods were given very limited coverage which is a pity since these are of increasing importance in the food industry. Chap-
408
Book Reviews
ter four described the theory of analytical methods for specific food constituents, chapter five provided detailed experimental procedures for the estimation of major food constituents and chapter six gave examples of more general food studies. These last three chapters constitute the experimental section of the book which is clearly the most important, providing students and others with clear instructions for performing all of the standard determinations. This section is very useful, serving as a reference work and handbook, although no literature is cited. However, chapter seven does provide a limited list of alternative reading material. In conclusion I thought this book, despite some omissions, is overall a good guide to “conventional” food analytical techniques and extremely good value at the price. R.H. Wilson
Keith B. Oldham and C. Myland, Fundamentals of Electrochemical Science, Academic Press, San Diego, CA, 1994 (ISBN O-12-525545-4). xxii + 474 PP. This book aims to cover the fundamentals of electrochemical science and does so in a fairly comprehensive manner. The authors, however, admit that the subject is very broad and certain important areas such as modified electrodes and semi-conductor electrodes are not covered because of their lack of expertise in the area. The book is not aimed at a particular audience but is in more depth than would be required for those who just want a simple introduction or overview. The mathematics will put off the faint hearted and most undergraduates, but the book would be a good starting point for more advanced levels of study where a good understanding of electrochemical principles is required. The recommendation of a book on electrochemistry often depends on the sign convention used. The terms working and reference electrode are used where ever possible by the authors and the use of positive and negative electrodes is avoided. The anodic current at the working electrode is treated as positive and the increasingly positive electrode is plotted to the right in this book.
The book starts with two revision chapters on electricity and ionic solutions. It then goes on to cover electrochemical cells, electrodes, electrode reactions and polarisation as separate chapters. This is followed by a chapter on transport and then steady state voltammetry, the electrode interface, the use of periodic signals and transient voltammetry are covered. A bibliography of reviews is provided plus a glossary, physical constants, etc. The book is written from an electrochemical point of view and therefore does not discuss analytical aspects of electrochemistry in any detail, however, it would certainly be useful for an electroanalytical chemist who wished to understand electrochemical processes in more depth. The book uses clear examples and simple illustrations to convey ideas. Problems are used to help place equations in context. In general this is a clearly written book on electrochemistry which will be of use to anybody wishing to understand the subject in reasonable depth. G.M. Greenway
B.J. Alloway (Ed.)., Heavy Metals in Soils, 2nd edn., Blackie, Glasgow, 1995 (ISBN o-7514-0198-6). xiv + 368 pp. Price f75.00. This is a thoroughly revised version of the first edition that appeared in 1990 and is aimed primarily at environmental and soil scientists. There are fifteen international contributors and fourteen self contained and extensively referenced chapters. The early chapters consider the physical and chemical properties and sources of heavy metals in soils and the analytical techniques (including sampling and sample treatment) necessary for their determination. These are followed by ten chapters discussing individual elements including arsenic, cadmium, chromium, nickel, copper, lead, manganese, cobalt, mercury, selenium and zinc. The contents are very readable and full of useful quantitative information (particularly in the form of tables) relating to the distribution of heavy metals in soils, e.g., normal concentration ranges for heavy metals in soils and plants, which is often difficult to access. The presentation is of a consistently high quality and there is a good index and appendices.