One of the hottest, yet most neglected topics in sample preparation is evaporation. Most chromatographic methods require some form of sample cleanup prior to injection into a HPLC or GC system to prevent clogging or undesired interferences. Many users opt to skip evaporation and perform a direct injection of the purified sample, but this is not always feasible.
Often, sample prep includes an evaporation and reconstitution step that adds time and complexity to the workflow. With new state-of-the-art instrumentation, evaporation can be done on plates, tubes, or vials in a shorter amount of time, and with minimal intervention. The New Generation of nitrogen evaporators, such as the TurboVap® 96 Dual, TurboVap® LV and TurboVap® II from Biotage offer revolutionary performance and a user-friendly interface.
Control of the nitrogen flow and gradient programming are critical for optimum evaporation. When beginning the evaporation procedure, it is a good idea to start with a gentle flow, as to not cause cross-contamination of samples. As the evaporation of solvent increases, so does the space above the sample, which can permit an increase of the gas flow through a programmed method. This approach increases the rate of evaporation. Easily programmed and stored methods allow for automated integration and reproducible performance from day to day.
With older systems, the evaporation process was hard to monitor and determine when complete. Often the user had to pause the evaporation and place their head into the evaporation chamber filled with dangerous fumes. Through advances in design and manufacturing, solvent evaporators are now available with clear tanks and lids allowing the sample evaporation process to be observed from a safe distance. The use of colored lamps indicates when evaporation is in process, completed, or has encountered an error. The keyword is visibility, and this is a significant benefit for lab personnel.
Most evaporation systems require the purchase of multiple racks to accommodate the range of vessels routinely used in a lab. Newer racks feature adjustable tube holders allowing the use of one rack for multiple vessel sizes. Labs can have fewer racks and save money at the same time. Some racks are even designed to accommodate processing samples on a positive pressure manifold and transferring them directly to the evaporation system, thus eliminating costly sample transfer steps. The TurboVap® P+ is a prime example of how samples processed in cartridges can be collected and immediately transferred for efficient evaporation.
Many improvements have been made to solvent evaporators in recent years which aim to improve the workflow for labs performing sample preparation and chromatography. We have found in our lab that the TurboVap® Next Generation Solvent evaporators offer faster, simpler, and more efficient evaporation of samples prior to reconstitution and analysis by LC or GC technology.
Find out more about the Next Generation TurboVap®.
Next Blog: The Beauty of storing evaporation methods!