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Stable isotope biogeochemistry is not exactly what you would call a mass-market activity. As a result, we spend a lot of time and effort modifying commercially available lab equipment to suit our needs, as well as making a lot of our own stuff. Not to mention that tinkering with lab equipment is way more fun than actually working! Elise Kleeman has put together some photos and details about a few of our gadgets and modifications, which are posted here for the benefit of other scientitsts who may be facing similar problems. These are not necessarily the best solutions to the problems, but you can be assured that they at least work. If you would like more detailed information on any of these projects, please feel free to email me and I'll do what I can to help.
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| Freeze Dryer |
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There are lots of commercially available freeze dryers, but getting one to produce an organic-free blank (as viewed through a GC/MS) can be really tough. This page describes our efforts with a Virtis K-series benchtop freeze dryer, which after rather extensive modifications works very nicely!
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| TurboVap |
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The turbovap is a very efficient alternative to the traditional rotovap. When the pressure regulator on ours died (after only 6 months...), we took the opportunity to make some changes.
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| Syringe Holder |
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This simple syringe holder solves the main problem with the commercially available horizontal ones, namely that the (almost invisible) needles stick out to the side and are unprotected from wandering hands.
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GC Blowdown System
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I wasn't happy with any of the commercial systems for drying down solvent in GC vials, so I made my own for under $500. Details of the system are posted here.
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Improved GC Blowdown System
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There were a few, um, issues with the earlier version, so we built this improved blowdown system (Model II!) for dealing exclusively with GC vials.
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Vacuum Filtration Base
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A common problem for us is filtering particles out of organic solvents, and collecting the solvent into a small vial with a minimum of handling. We devised this system which uses a glass "filter dome" and allows you to filter solvents directly into a glass VOA vial, ready for the turbovap. The system also works well with solid-phase extraction columns, and greatly speeds the procedure.
Update (Mar 08): We made our original bases out of delrin plastic. They worked well for about 3 years, but spilled solvents have gradually etched the plastic to such an extent that they no longer seal well. If I were doing this again (soon...) I would make them out of aluminum and have them anodized.
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Porewater Squeezer
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How to efficiently collect filtered porewater from soupy marine sediments? There are nearly as many methods as there are oceanographers, but we'll post our effort anyway. These are nearly identical to a design by Bill Ussler (at MBARI), and are based on the original design by Bill Reeburgh (now at U.C. Irvine).
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