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Comparison of fused silica and other glass columns in gas chromatography
Jomud of Chrornmogqhy. 236 (1982) 535-536 Ekvier scientiiic Publishing Company, Amstexdazn -
Printed in The Netherlands
CHROM. 14,407
Book Review
Comparisons of fused silica and other giass columns in gas chromatography, by W. G. Jennings, Alfred Hiithig Verlag, Heidelberg, 1981, VIII f SO pp., 39 figs., price DM 38.00, US$ 19.00, ISBN 3-7785-0729-X. initial impressions of this book are highly favourable. The clear, bold print and distinct figures immediately catch the eye, whilst the convenient, compact size make the book easy to carry around and refer to. Each chapter and each section within a chapter are clearly headed and preceeded by a useful summary in darker print_ As fused-silica capillary columns are still relatively new, it is good to see a book extolling their virtues -and drawing attention to their (fewer) drawbacks. Chapter 1 is a general introduction to gas chromatography and the parameters which a&it performance. In particular, the theory behind column separation of components is explained in simple terms -and no equations!leading on to the pros and cons of capillary and packed columns_ Having decided that capillaries outperform packed columns in efficiency, speed, sensitivity, inertness and price, Chapter 2 discusses Materials of construction. Basically, this can be summarized by, firstly, u&y glass (and not plastic or metal)‘! Having answered that (because it is more inert, but not inert enough), one has to choose which glass? The bulk and surface structures of different glasses (soda-lima, borosilicate, lead and fused silica/quartz) are well explained and this reveals how surfaces can have a variety of Lewis acid and silanol active sites. Finally, attention is drawn to the special problems of drawing capillaries from high purity fused silica. Once a capillary has been drawn, the surface active sites mentioned above, must be deactivated. Chapter 3 provides a highly comprehensive survey of both the theory and practice of glass and fused-silica capillary pretreatment_ This must cover all the common techniques used, including leaching, etching, surface active agents, salt deposition, deactivation using polymer films, polysiloxanes and silylation, and relative merits of each in deactivating Lewis acid or silanol sites (and other side effects) are discussed in detail. When the column has been appropriately treated, the author proposes that it should be evaluated for degree of inertness (Chapter 4)_ This can be done prior to, and after coating with the final liquid phase (the book is concerned principally with wall-coated open tubular columns) using a variety of test compounds, and procedures such as varying temperature, phase “bleed”, adsorption of compounds (e.g., tailing and loss of sample) and compound degradation. This is a particularly useful chapter, incorporating many hints for chromatographers wanting to evaluate the quality of their columns. In passing, it would have helped, had the peaks in Fig_ 22 been numbered, as identification using Table 3 is otherwise impossible. Chapter 5 -Physical characteristics of the columnshould really be renamed Physical characteristics of the fused silica column, since it devoted to the many
FlUOK REVIEW
536
advantages to be-gained from a flexible column. One immediately obvious gain is to do away with the need for flame straightening of coiumn ends, which can not only produce active sites, but can enrage operators trying to mount long, fragile straight ends into instruments! Fused-silica columns are very thin, so they are coated with, commonly, a polyimide sheath. ihe book stresses the need for column ends to be properly cut to-avoid projecting sheath fragments, and there are some excellent photographs and practical instructions for perfecting this technique. Chapter 6 -Cost comparisons of glass and fused silica columns- seems entirely irrelevant. The whole chapter is only two pages, of which one quarter is- a summat of the other three quarters. What the author says here -that fused-silica capillaries are cheaper than glass because___- could be said in one paragraph at the end of, say, Chapter 2. The final chapter (7) consists of a diverse selection of Application examples, and is simply an illustration of what can be achieved with fused-silica columns_ The message seems to be that capillary gas chromatography is becoming evermore versatile, capable of handling a wider range of high and low molecular weight compounds and the advent of fused-silica columns has given this a healthy boost. So who is this book aimed at, and what will the reader learn from it? The book is written in the casual style common to American authors, and despite occasional eccentricities of spehing and sentence construction, I found it very easy to read and extremely informative. I anticipate that it will appeal most to people actually using capillary gas chromatography who would like to understand the basic theory and principles -without the mathematics. At the same time, there is a surprising amount of practical advice for such a siim volume. 3rigi2ron
(C&at Britain)
RICJSARD
L. PATIENCE
Printed in The Netherlands
CHROM. 14,407
Book Review
Comparisons of fused silica and other giass columns in gas chromatography, by W. G. Jennings, Alfred Hiithig Verlag, Heidelberg, 1981, VIII f SO pp., 39 figs., price DM 38.00, US$ 19.00, ISBN 3-7785-0729-X. initial impressions of this book are highly favourable. The clear, bold print and distinct figures immediately catch the eye, whilst the convenient, compact size make the book easy to carry around and refer to. Each chapter and each section within a chapter are clearly headed and preceeded by a useful summary in darker print_ As fused-silica capillary columns are still relatively new, it is good to see a book extolling their virtues -and drawing attention to their (fewer) drawbacks. Chapter 1 is a general introduction to gas chromatography and the parameters which a&it performance. In particular, the theory behind column separation of components is explained in simple terms -and no equations!leading on to the pros and cons of capillary and packed columns_ Having decided that capillaries outperform packed columns in efficiency, speed, sensitivity, inertness and price, Chapter 2 discusses Materials of construction. Basically, this can be summarized by, firstly, u&y glass (and not plastic or metal)‘! Having answered that (because it is more inert, but not inert enough), one has to choose which glass? The bulk and surface structures of different glasses (soda-lima, borosilicate, lead and fused silica/quartz) are well explained and this reveals how surfaces can have a variety of Lewis acid and silanol active sites. Finally, attention is drawn to the special problems of drawing capillaries from high purity fused silica. Once a capillary has been drawn, the surface active sites mentioned above, must be deactivated. Chapter 3 provides a highly comprehensive survey of both the theory and practice of glass and fused-silica capillary pretreatment_ This must cover all the common techniques used, including leaching, etching, surface active agents, salt deposition, deactivation using polymer films, polysiloxanes and silylation, and relative merits of each in deactivating Lewis acid or silanol sites (and other side effects) are discussed in detail. When the column has been appropriately treated, the author proposes that it should be evaluated for degree of inertness (Chapter 4)_ This can be done prior to, and after coating with the final liquid phase (the book is concerned principally with wall-coated open tubular columns) using a variety of test compounds, and procedures such as varying temperature, phase “bleed”, adsorption of compounds (e.g., tailing and loss of sample) and compound degradation. This is a particularly useful chapter, incorporating many hints for chromatographers wanting to evaluate the quality of their columns. In passing, it would have helped, had the peaks in Fig_ 22 been numbered, as identification using Table 3 is otherwise impossible. Chapter 5 -Physical characteristics of the columnshould really be renamed Physical characteristics of the fused silica column, since it devoted to the many
FlUOK REVIEW
536
advantages to be-gained from a flexible column. One immediately obvious gain is to do away with the need for flame straightening of coiumn ends, which can not only produce active sites, but can enrage operators trying to mount long, fragile straight ends into instruments! Fused-silica columns are very thin, so they are coated with, commonly, a polyimide sheath. ihe book stresses the need for column ends to be properly cut to-avoid projecting sheath fragments, and there are some excellent photographs and practical instructions for perfecting this technique. Chapter 6 -Cost comparisons of glass and fused silica columns- seems entirely irrelevant. The whole chapter is only two pages, of which one quarter is- a summat of the other three quarters. What the author says here -that fused-silica capillaries are cheaper than glass because___- could be said in one paragraph at the end of, say, Chapter 2. The final chapter (7) consists of a diverse selection of Application examples, and is simply an illustration of what can be achieved with fused-silica columns_ The message seems to be that capillary gas chromatography is becoming evermore versatile, capable of handling a wider range of high and low molecular weight compounds and the advent of fused-silica columns has given this a healthy boost. So who is this book aimed at, and what will the reader learn from it? The book is written in the casual style common to American authors, and despite occasional eccentricities of spehing and sentence construction, I found it very easy to read and extremely informative. I anticipate that it will appeal most to people actually using capillary gas chromatography who would like to understand the basic theory and principles -without the mathematics. At the same time, there is a surprising amount of practical advice for such a siim volume. 3rigi2ron
(C&at Britain)
RICJSARD
L. PATIENCE