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February / March 2012
integrated guard column. Theoretical predictions suggest that the integrated guard column should lose about 5% of its resolving power, and the data in this case gave less than 10%.
The loss of signal to noise that was observed when comparing an integrated guard with a press fitted guard column was attributed to the extra dead volume with the press fit connector. An integrated column does not suffer from this extra dead volume and so as a result the signal to noise is better.
The use of guard columns both in HPLC and also in GC is still not optimal. There are many opportunities to reduce costs and to improve the quality of the data that is being produced. Using an integrated guard column in a GC environment ensures that not only is the performance optimised for that specific column, resulting in a better signal to noise ratio, but also that the column lifetime is improved. As was demonstrated with the separation of the PAH’s it is possible to get better resolution over a longer period of time.
Conclusions
The use of an integrated guard column has advantages when compared to a press fitted guard and also a situation where a guard column is not used. In the first experiment where a length of the column was removed and a comparison made of the resultant efficiencies, it can be predicted that
removing 13 metres of the column would result in a loss of 25% in resolution which was very close to the data obtained for this experiment. Comparing this loss in resolution with the integrated guard column where only 10% of the stationary phase was lost (3 metres out of 30 metres), it can be seen that there are advantages to using an
Correct use of guard columns can substantially reduce costs and also improve the performance of a laboratory. Many users see the addition of another connector to attach guard columns particularly within the field of GC, as being fraught with difficulties, and a potential solution to this is to use the integrated version of the columns being used.
Analytical Science / Pharmaceutical Technology Books from ILM Publications
Monolithic Chromatography and its Modern Applications
Edited by Perry G. Wang, US FDA, USA The ChromSoc Separation Science Series
ISBN: 978-1-906799-03-8 • 2010 • Hardback 648 pp • £200 / $300
“ Likely to inspire both seasoned scientists already working with monoliths and novices who want to encounter them for the first time and see how they can be applied in their work... a helpful resource for scientists and practitioners engaged in analytical chemistry and related fields. ”
F. Svec, Lawrence Berkeley National Laboratory, USA, in Analytical and Bioanalytical Chemistry
A Practical Guide to Implementing Clinical Mass Spectrometry Systems
By Neil Leaver, UK
ISBN: 978-1-906799-10-6 • 2011 Paperback • 96 pp • £30 / $45
“ ...written from a very practical point of view, covering subject matter that is usually learned through experience and is not discussed in standard texts or regulatory guidelines... a valuable reference book for
clinical laboratories. ”
Sanjay Garg, University of Auckland, New Zealand, in Bioanalysis
Counterfeit Medicines Volume I: Policy, Economics and Countermeasures
Edited by Albert I. Wertheimer, Temple University, USA and Perry G. Wang, US FDA, USA
ISBN: 978-1-906799-08-3 • February 2012 Hardback • 154 pp • £40 / $60
To order these publications: Tel: +44 (0)1727 855574
Web:
www.ilmpublications.com Email:
orders@ilmpublications.com
This book provides a concise account of the history, policy and law, and financial and economic aspects surrounding pharmaceutical product counterfeiting, as well as some of the countermeasures available to organisations. It discusses the problems experienced in lesser developed countries and reports the activities and findings of governments and agencies around the world. The safety concerns regarding illicit online pharmacies are reviewed and an overview is given of the regulatory efforts attempting to stem their negative effects.
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