- Email: [email protected]
Troubleshooting LC systems
T&ma, Vol. 37, No. 2, pp. i-ii, 1990 Pergamon Press plc. Printed in Great Britain.
BOOK REVIEWS
Computerized Multiple Input Chromatography:
M. KALJURAND and E. KOLLIK,Ellis Horwood, Chichester, 1989. Pages 225.
Price f45.00 The authors explore a number of applications of computer control and data inte~retation in gas and liquid chromatography. Their principal interest is in correlation chromato~aphy (CC) in which a pseudo-random binary sequence of overlapping injections is coupled with cross-correlation between the sequence and the resulting signal to improve the signal to noise ratio for separations of trace levels of analytes. They then examine the application of sequential repeated injections to monitor changes in samples with time or conditions, and discuss column switching techniques in which time slices from the first column are fed to a second column. In both cases they emphasize the need to use a computer to control the multiple injections and monitor the results and describe the experimental systems used for injection and column switching. The overall theme of the book is the application of info~ation theory to these chromatographic processes. Unfortunately the authors often mix techniques and it is often difficult to decide whether CC or repeated injection with fast separations is being used. The applications concentrate on thermal analysis, including pyrolysis of polymers, and trace constituents in environmental samples. The book was completed in January 1987 but there are few references even to 1986, so that some sections, particularly those referring to computers, are dated. The advantages of the Apple II for control are described but no mention is made of the much more powerful computing ability of the IBM (or its clones). Newer instruments and intelligent integrators would also now routinely incorporate many of the required control facilities. The book is interesting to read (the matrix algebra can be skipped), but with relatively few applications to real samples other than pyrolysis, its value will be mainly as a general background to chromatography. R. M. Troubleshooting
LC Systemr
JOHNW.
DOLAN
SMITH
and LLOYDR. SNYDER,Humana, New Jersey, 1989. Pages viii + 515. $65.00
(U.S.), Export $75.00. The authors of this text am very we11known in the field of liquid chromato~aphy, from their articles and short courses. Professor Snyder has also recently been appointed editor of J. Cftromarogrrzph~ and so even before opening this book the reader can be assured that its contents will merit consideration. The book is best described as a reference manual and it is similar in design to those books which describe the function, efficient use and possible faults that may occur in a car or a human body. The three sections of the book attempt to condense the expertise of many practical LC workers into an easy-to-use format. The first section examines LC difficulties in terms of problem area, primary symptom, secondary symptom and likely cause. This approach is expanded in an extensive problem-isolation table which is essentially a flowchart with 676 rows and 6 column headings. Examples explaining the use of this tabie are given and whereas many problems can be solved through use of this guide, others, such as specific eiectronic problems, are considered outside the expertise of most readers. The logic involved in isolating and correcting LC problems is similar to that found in computer-based expert systems such as “The HPLC Doctor”. Other basic considerations such as elementary separation theory, preventative procedures and good troubleshooting habits are covered in this section of the book. Individual LC modules are described in the next section and this occupies about half of the book. Each of the eight chapters here is self-contained and each describes a module, e.g., pumps, columns, detectors etc., in detail. Good use is made of diagrams and photographs, and principles of operation and maintenan~ are included together with extensive coverage of possible problems and their solutions. The final section deals mainly with problems associated with separation difficulties. Reasons for band tailing and peak distortion are given and other changes in the appearance of the chromatogram are discussed. Solutions to problems in quantification, gradient elution and sample pretreatment are offered. The index is comprehensive and deals efficiently with the inevitable overlap of subject material. I checked some of the advice offered on dealing with practical problems, with the chief technician in our HPLC ia~mtories. The resulting comments were favourable: “That’s precisely what I did” or “That‘s just what I would do”. In conclusion, a very useful book for beginners and those on their way to becoming competent in practical LC. P. J. Cox Advances in Drop: Therapy of Gastrointestinal
Ulceration: ANDREW GARNER and BRENDAN J. R. WHtTTLE(editors), Wiley,
Chichester, 1989. Pages xvi + 306. E40.00. The 20 chapters in this book are based on the proceedings of the 38th Annual Biological Council Symposium on Drug Action held at the Royal Institution in London on 11-12 April 1988. The topic is presented from a physiologicaI/ pharmacological viewpoint with chemistry very much in the background. As the emphasis is not on chemistry the book might be regarded as unsuitable for analytical chemists. However, much analytical effort today is directed towards producing safe and effective drugs and the world’s two top selling (i.e., money-making) drugs, ranitidine and cimetidine, are both anti-ulcer drugs. These two histamine Hz-antagonists together with other possible anti-ulcer agents are of much interest to the pharmaceutical industry, where many analytical chemists work.
BOOK REVIEWS
Computerized Multiple Input Chromatography:
M. KALJURAND and E. KOLLIK,Ellis Horwood, Chichester, 1989. Pages 225.
Price f45.00 The authors explore a number of applications of computer control and data inte~retation in gas and liquid chromatography. Their principal interest is in correlation chromato~aphy (CC) in which a pseudo-random binary sequence of overlapping injections is coupled with cross-correlation between the sequence and the resulting signal to improve the signal to noise ratio for separations of trace levels of analytes. They then examine the application of sequential repeated injections to monitor changes in samples with time or conditions, and discuss column switching techniques in which time slices from the first column are fed to a second column. In both cases they emphasize the need to use a computer to control the multiple injections and monitor the results and describe the experimental systems used for injection and column switching. The overall theme of the book is the application of info~ation theory to these chromatographic processes. Unfortunately the authors often mix techniques and it is often difficult to decide whether CC or repeated injection with fast separations is being used. The applications concentrate on thermal analysis, including pyrolysis of polymers, and trace constituents in environmental samples. The book was completed in January 1987 but there are few references even to 1986, so that some sections, particularly those referring to computers, are dated. The advantages of the Apple II for control are described but no mention is made of the much more powerful computing ability of the IBM (or its clones). Newer instruments and intelligent integrators would also now routinely incorporate many of the required control facilities. The book is interesting to read (the matrix algebra can be skipped), but with relatively few applications to real samples other than pyrolysis, its value will be mainly as a general background to chromatography. R. M. Troubleshooting
LC Systemr
JOHNW.
DOLAN
SMITH
and LLOYDR. SNYDER,Humana, New Jersey, 1989. Pages viii + 515. $65.00
(U.S.), Export $75.00. The authors of this text am very we11known in the field of liquid chromato~aphy, from their articles and short courses. Professor Snyder has also recently been appointed editor of J. Cftromarogrrzph~ and so even before opening this book the reader can be assured that its contents will merit consideration. The book is best described as a reference manual and it is similar in design to those books which describe the function, efficient use and possible faults that may occur in a car or a human body. The three sections of the book attempt to condense the expertise of many practical LC workers into an easy-to-use format. The first section examines LC difficulties in terms of problem area, primary symptom, secondary symptom and likely cause. This approach is expanded in an extensive problem-isolation table which is essentially a flowchart with 676 rows and 6 column headings. Examples explaining the use of this tabie are given and whereas many problems can be solved through use of this guide, others, such as specific eiectronic problems, are considered outside the expertise of most readers. The logic involved in isolating and correcting LC problems is similar to that found in computer-based expert systems such as “The HPLC Doctor”. Other basic considerations such as elementary separation theory, preventative procedures and good troubleshooting habits are covered in this section of the book. Individual LC modules are described in the next section and this occupies about half of the book. Each of the eight chapters here is self-contained and each describes a module, e.g., pumps, columns, detectors etc., in detail. Good use is made of diagrams and photographs, and principles of operation and maintenan~ are included together with extensive coverage of possible problems and their solutions. The final section deals mainly with problems associated with separation difficulties. Reasons for band tailing and peak distortion are given and other changes in the appearance of the chromatogram are discussed. Solutions to problems in quantification, gradient elution and sample pretreatment are offered. The index is comprehensive and deals efficiently with the inevitable overlap of subject material. I checked some of the advice offered on dealing with practical problems, with the chief technician in our HPLC ia~mtories. The resulting comments were favourable: “That’s precisely what I did” or “That‘s just what I would do”. In conclusion, a very useful book for beginners and those on their way to becoming competent in practical LC. P. J. Cox Advances in Drop: Therapy of Gastrointestinal
Ulceration: ANDREW GARNER and BRENDAN J. R. WHtTTLE(editors), Wiley,
Chichester, 1989. Pages xvi + 306. E40.00. The 20 chapters in this book are based on the proceedings of the 38th Annual Biological Council Symposium on Drug Action held at the Royal Institution in London on 11-12 April 1988. The topic is presented from a physiologicaI/ pharmacological viewpoint with chemistry very much in the background. As the emphasis is not on chemistry the book might be regarded as unsuitable for analytical chemists. However, much analytical effort today is directed towards producing safe and effective drugs and the world’s two top selling (i.e., money-making) drugs, ranitidine and cimetidine, are both anti-ulcer drugs. These two histamine Hz-antagonists together with other possible anti-ulcer agents are of much interest to the pharmaceutical industry, where many analytical chemists work.