Many industries rely on a nitrogen blowdown evaporator as a key step in processing their samples. These industries include environmental testing, agriculture, food and beverage, medicine, quality assurance, forensics, oil and grease, and many more. So, what exactly is it?
A nitrogen blowdown evaporator is a key piece of lab equipment that is used to prepare samples for chromatography, mass spectrometry or other analysis by removing excess solvent. The process works by lowering the vapor pressure above the sample, allowing excess solvent to evaporate more quickly. This method of concentration is especially effective for small volume samples in volatile or semi-volatile organic solvents. The precision of nitrogen blowdown makes it a great choice for those who are looking to evaporate to complete dryness or stop at a specific endpoint.
Compared to a heated sample, solvent molecules in a sample under ambient conditions are very low energy and therefore slow-moving. Due to this lack of speed, only some molecules can be vaporized and separated from the sample. Combined with the vapor pressure above the sample this causes many molecules to return, slowing down evaporation. This is where nitrogen blowdown evaporation is a useful tool. The evaporator works by applying a steady stream of nitrogen gas just above the surface of the sample, which gently pushes the vapor-saturated air out, preventing it from returning to the remaining liquid. 
The nitrogen gas cools the sample slightly, which decreases the energy of the molecules and slows them down, diminishing their ability to vaporize. To speed the molecules back up, heat can be applied in the form of a water bath or dry block in order to reenergize the sample. The combination of nitrogen blowdown and heat quickly vaporizes the molecules, leaving a perfectly evaporated sample behind. If you are using a water bath, it should be set to a few degrees lower than the boiling point of your sample in order to achieve maximum concentration. On average, it takes only twenty-five minutes to safely concentrate a 10mL sample of methylene chloride using a nitrogen blowdown evaporator. This is compared to evaporating samples by hand, which can be a time-consuming process. For a few samples this can be justifiable, but for regular use, evaporation by hand is an inefficient process.
Nitrogen blowdown is gentle on the sample and does not require any consumables, making it an affordable and safe choice. We offer three product lines of nitrogen blowdown evaporators – the most-popular N-EVAP and its counterparts, MULTIVAP, and MICROVAP. You can learn more about the differences between these products, and use our quick product finder to figure out which one is the best fit for your needs.
Nitrogen can be expensive to purchase and inconvenient to store. We are proud to make a lightweight and portable nitrogen gas generator, called the NITRO-GEN. It is the perfect solution for any laboratory looking for a low-cost solution to integrate with an existing clean air line. It also boasts a reduction in your carbon footprint, removing the emissions of transporting nitrogen cylinders to and from your lab.
For more information on nitrogen blowdown evaporation or on any of our products, reach out to our team at sales@organomation.com or use our live chat during normal business hours.