HPLC [...]... can be collected and concentrated to recover the separated materials (preparative mode) It is very important to remember that HPLC is both an analytical and a preparative tool Often the preparative capabilities of the HPLC are overlooked While normal analytical injections contain picogram to nanogram quantities, HPLCs have been used to separate as much as 1 lb in a single injection (obviously by a. .. industrial methods development laboratories They usually have an autosampler, a multi-solvent gradient, at least a dual-channel, variable UV detector and computer-based control, and data processing system for reports They may add a fraction collector to be used in standards preparation Some laboratories will replace the variable detector with a diode array detector/computer combination that can run... the sample is on the bed, it can be washed and then eluted in a step-bystep manner with increasingly stronger solvent These are surprising powerful tools for quick evaluation of the effectiveness of a packing material, sample clean-ups, and broad separations of classes of materials They are available in almost any type of packing available for HPLC separations: partition, ion exchange, adsorption, and... reproduction on the same standard set While the HPLC can be used in a variety of research and production operations, there are a few places where it really shines Because it can run HPLC: A Practical User’s Guide, Second Edition, by Marvin C McMaster Copyright © 2007 by John Wiley & Sons, Inc 3 4 ADVANTAGES AND DISADVANTAGES OF HPLC underivatized mixtures, it is a great tool for separating and analyzing crude... separations are carried out on glass, plastic, or aluminum plates coated with thin layers of solid adsorbant held to the plate with an inert binder Plates are coated with a thick slurry of the solid and binder in a volatile solvent, then allowed to dry before using Multiple samples and standards are each dissolved in volatile solvent and applied as spots across the solid surface and allowed to evaporate... no, maybe It really depends on what you are trying to achieve HPLC s virtue lies in its versatility! I have used it to separate compounds of molecular weights from 54 to 450,000 Daltons Amounts of material to be detected can vary from picograms and nanograms (analytical scale) to micrograms and milligrams (semi-preparative scale) to multigrams (preparative scale) There are no requirements for volatile... released and the fluid returns to the gaseous state leaving purified sample as a solid Doping of carrier gas with small amounts of volatile polar solvents such as methanol can be used to change the polarity of the supercritical fluid and modify the separation Advantages of SFC include many of the characteristics of an HPLC separation: high resolving power and fast run times, but with much easier sample... containing 10–50 ng of sample Typical runs are made at 1–2 mL/min and take 5–15 min (isocratic) or 1 hr (gradient) 1.2 OTHER WAYS TO MAKE MY SEPARATION Obvious there are many other analytical tools in the laboratory that could be used to make a specific separation Other techniques may offer higher 10 ADVANTAGES AND DISADVANTAGES OF HPLC sensitivity, less expensive equipment, different modes of separation,... Separation is achieved by standing the plate in a shallow trough of developing solvent and allowing solvent to be pulled up the plate surface by capillary action Once solvent has risen a specific distance, the plates are dried and individual compounds are detected by UV visualization or by spraying with a variety of reactive chemicals Identification is made by calculating relative migration distances and/or... past I have taught HPLC extension courses for 16 years and have consulted on a variety of other manufacturers’ systems for at least that long I will try to give you an objective look at the various types of problems that HPLC can solve and my best recommendation for the equipment you’ll need to solve each one and, at least, a ballpark price (2006 vintage) for each system HPLC: A Practical User’s Guide, . of material to be detected can vary from picograms and nanograms (analytical scale) to micro- grams and milligrams (semi-preparative scale) to multigrams. (preparative mode). It is very important to remember that HPLC is both an analytical and a preparative tool. Often the preparative capabilities of the HPLC are