Stainless steel needles and glass pipettes - they're both used on Organomation's parallel evaporators to deliver nitrogen gas onto the sample's surface. If they both serve the same function, you may be asking yourself "How do I know which option is best for me?" This article will explain the differences between them and when each is recommended, so you can make an informed decision for your lab.
Stainless Steel Needles
All Organomation blowdown evaporators come standard with 4 inch, 19 gauge stainless steel needles, as we've found that they are highly effective for the majority of customer applications. This specific needle size can accommodate almost all sample tube sizes, and provides a balance between evaporation speed and gas consumption. For labs drying down high-volume samples, 16 gauge needles are also available to speed up the evaporation process. All needles are made with 304 stainless steel and have a luer lock fitting that easily attaches and detaches from the instrument's manifold.
Gas delivery needles can be used for essentially any application, besides those where metal contamination is a concern. They are reusable and can last for many years when properly maintained, making them a cost-effective option for labs on a strict budget. Since they are designed to be used again and again, these needles should be washed and dried after each use to prevent contamination between sample batches. Learn how to clean gas delivery needles between each use.
Glass pipettes are a great disposable option that are made to be thrown away after each use. They are mainly used by laboratories that do not have the time/resources to regularly maintain the cleaning steps above, or are worried that cross-contamination may still occur, even with sterilization. To utilize pipettes with Organomation's blowdown evaporators, pipette adapters must be installed on the luer lock fittings in place of needles. There are two pipette adapter styles depending on your preference - a fluted nut style (shown in the photo above) (Catalog# NA0636) and a hose barb style (Catalog# NA0637). Both adapter styles make it easy to attach and detach the pipettes to the unit. Unlike needles, Organomation does not sell the actual glass pipettes, however, they are readily available from a wide range of companies.
Personal preference can also be the deciding factor between using stainless steel needles or disposable glass pipettes. A lab tech may not have high concerns for contamination during sample evaporation, but just prefers the use of pipettes. Due to the adaptability of Organomation's evaporators, you can also easily switch back and forth between both options, which can be especially helpful if you work with a variety of applications.