Sample Preparation Mastery: Expert Insights on Evaporation Techniques for Chromatography

Dive into the world of sample preparation with industry expert Wade Hasenour as he shares invaluable insights on rotary evaporation, centrifugal evaporation, and freeze drying. Learn about the latest advancements, challenges, and future trends in sample prep techniques for chromatography. Discover how to choose the right method for your needs, optimize your workflow, and leverage automation for better results. Whether you're a seasoned chromatographer or just starting out, this video offers essential knowledge to enhance your sample preparation skills and achieve more reliable outcomes in your research.

Video Transcription

Interviewer: Hi Wade, I was hoping you could briefly introduce yourself and tell us about your current role.

Wade:
Yeah, thanks for having me on here. I currently serve at Genevac as a Regional Sales Manager, and I cover the Midwest, South, and Southeast regions.

My career began with a strong foundation in biochemistry. I worked in quality assurance in a lab, then moved into pharmacokinetics and worked in that kind of lab environment as well. After that, I transitioned into a sales role working for Shimadzu, where I specialized in chromatography systems. Later I joined Büchi, where I managed the entire product portfolio. And now I’m at Genevac, where I focus mainly on centrifugal evaporation.

Interviewer: As you know, we spend a lot of time here talking about chromatography and mass spectrometry. Today I was hoping we could talk about sample preparation. I’m curious: what are some of the most significant changes or advancements you’ve observed in sample preparation throughout your career?

Wade:
In sample preparation, the biggest transformation I’ve seen is around robotics and automation. There’s a much stronger focus on it now. Companies are hiring consultants to look at workflows and ask:

• Where can we improve this?
• How do we make it easier?
• How do we reduce time in production, whether that’s for an API, an oligonucleotide, whatever it may be?

The goal is to improve throughput and profitability.

While chemists focus on the quality of their work, upper management is pushing for automation and more hands-off approaches. That reduces liability, lowers the chance of people being exposed to hazardous chemicals, and of course, “time is money” for commercial labs and many of our customers.

Interviewer: That makes all the sense in the world. I was hoping we could get into sample preparation techniques in general. I’m very familiar with nitrogen blowdown because that’s what Organomation specializes in, but could you walk us through some basic principles of rotary evaporation, centrifugal evaporation, and freeze-drying?

Wade:
Sure. As a basis, the first thing you need to understand—whether it’s rotary evaporation, centrifugal evaporation, or freeze-drying—is that everything is centered around pressure control.

When you reduce the pressure, it becomes easier to evaporate solvents in a more gentle way. All three techniques rely on that, but differ in how much you reduce the pressure and how you apply heat. By controlling pressure, you’re also controlling the effective boiling point and thus the temperature of your sample.

With rotary evaporation, the traditional method uses gentle heating via a water bath. Water is a great medium to transfer heat. In terms of efficiency and how well it evaporates, water is an excellent middle ground compared to IR lamps and other heating methods.

The rotating flask creates a thin film and large surface area, and the reduced pressure lowers the boiling point so solvents evaporate gently and efficiently. The vapor then goes to a condenser, gets cooled, and ends up in the receiving flask.

With centrifugal evaporation, the principle is similar—reduced pressure and heating—but typically the vacuum goes lower. This is especially useful for very temperature-sensitive samples like oligonucleotides, RNA therapeutics, ADCs, peptide linkers, etc.

You can, for example, run at around 40 °C at ~8 mbar. You place Falcon tubes or microplates into a rotor and evaporate many samples at once. It’s very high-throughput. Often IR is used for heating, which is gentle but can take longer. The big benefit is that you can process hundreds of samples simultaneously, so per sample, the time can actually be faster than doing them one by one on a rotary evaporator.

Both rotary and centrifugal evaporators can dry samples completely and are used at various points in the workflow—synthesis, purification, and formulation.

Freeze-drying (lyophilization) is a bit different but still in the same family. You lower the pressure so much that water (or other suitable solvents) goes from solid directly to gas—sublimation—with no liquid phase. This preserves the structure of the sample and is excellent for stability and shelf-life.

You can freeze-dry samples in trays, vials, Falcon tubes, flasks, and other formats. The idea is to freeze the sample and then pull off the frozen solvent directly into the gas phase, which is why freezing conditions can strongly influence crystallization and final product characteristics.

You often see all three technologies in the same lab: rotary evaporator for synthesis scale-ups or solvent exchange, centrifugal evaporation for high-throughput concentration or dry-down, and freeze-dryers for final formulations and long-term stability.

Interviewer: That’s very helpful. It’s always been easy to introduce rotary evaporation as “one sample at a time.” How do you see the transition to centrifugal evaporation in practice?

Wade:
A common pattern is this: you have a few chemists, each with their own rotary evaporator, doing one or two samples at a time. There’s no serious bottleneck.

But once the lab’s throughput increases, they hit that bottleneck—too many samples piling up. That’s when centrifugal evaporation becomes attractive: you can process dozens or hundreds of samples at once.

Another factor is solvent behavior. Some harsh or high-boiling solvents, like DMSO, are problematic on a rotary evaporator—they bump easily. Centrifugal evaporators use centrifugal force to help suppress bumping and boiling over, which prevents cross-contamination and sample loss. That centrifugal component is key—extra “gravity” keeps the liquid in place.

On a rotary evaporator, high-boiling solvents can be difficult to remove without bumping or risking analyte loss. But in a centrifugal evaporator, you can handle a wide range—from low-boiling to high-boiling solvents—more safely and gently.

And that’s really the point: preserving the analyte. When people hear “bumping,” they think “losing sample,” “destroying my yield,” and they’re right to be concerned.

Interviewer: You touched on efficiency, sample integrity, and cost-effectiveness. Could you expand on how the different techniques compare in those areas?

Wade:
Sure. I’ll put on my sales hat here.

The first question I have to ask clients—though I try to do it gently—is: What’s your budget and what scale are you working at?

• If someone says, “I have $5,000,” the realistic option is usually a rotary evaporator.
• Rotary systems can be benchtop or scaled up to industrial sizes.
• Centrifugal evaporators are typically high-throughput lab instruments; you don’t often see warehouse-sized centrifugal systems.

So cost-effectiveness is the first filter.

Then we talk application:

• If you’re working with a single low-boiling solvent and just a few samples, rotary evaporation is quick and efficient.
• If you’re working with many samples, mixed solvent systems, or very temperature-sensitive analytes, centrifugal evaporation or freeze-drying might be better.

For sample integrity, anything that significantly reduces pressure and allows you to keep temperatures low will help preserve sensitive compounds—proteins, oligos, peptides. That’s where centrifugal evaporation and freeze-drying shine. Rotary evaporation sometimes can’t get the pressure low enough, so bath temperatures or solvent boiling points may end up higher than the sample’s stability limit, and you risk denaturation or degradation.

For efficiency, if you only have a few samples, rotary evaporation is hard to beat for speed, especially with water as the heat transfer medium. Genevac also has instruments like the Rocket, which use water to transfer heat and are very efficient for low- to mid-boiling solvents, combining some advantages of both worlds.

But if you’ve got 1,000 samples, centrifugal evaporation wins on throughput per sample. The conversation with clients is always:

• What’s your sample load?
• Which solvents are you using?
• How sensitive is your analyte?
• And what’s your budget?

Interviewer: What types of samples or analytes are best suited for each of the main evaporation techniques?

Wade:
Broadly speaking:

• Rotary evaporation is ideal for APIs and classic organic synthesis—general solvent removal on flasks, reaction work-up, and straightforward solvent exchanges.
• Centrifugal evaporation is great for mixed solvent systems, temperature-sensitive analytes, and high-throughput workflows: RNA therapeutics, oligonucleotide synthesis, drug screening, diagnostic reagent kits, microplates, etc.
• Freeze-drying is best for biological samples, peptides, and analytes requiring long-term stability or shelf-life. It’s often the final formulation or storage step once purification and concentration are done.

Nitrogen blowdown (like Organomation’s systems) fits in as well—especially in workflows where you’re concentrating down to GC vials or small volumes, often after larger-scale evaporation.

Interviewer: From a sales perspective, I see many labs still using homemade nitrogen blowdown setups. We’re trying to move them toward dedicated equipment. You must encounter similar situations. Could you share a challenging sample prep scenario and how you dealt with it?

Wade:
Honestly, the story is often similar: hard solvents and sensitive samples.

DMSO is a big one. It doesn’t dry down well on rotary evaporators—it bumps, and people worry about losing sample. We get called in to “save the day” and often customize a solution.

Two groups stand out:

• Oligonucleotides and RNA therapeutics
• Labs working with mixed low- and high-boiling solvents

They’re worried about cross-contamination in well plates and maintaining integrity of very sensitive analytes. Competitive technologies sometimes don’t provide enough centrifugal force to keep everything in place, so vapor and droplets can move between wells during evaporation.

Our approach with Genevac is to position systems as anti-bumping, gentle evaporators. We add features like inert gas purging, which is useful when people use diethyl ether and other explosive solvents, so you avoid creating hazardous conditions.

The real challenge is almost always twofold:

1. Prevent cross-contamination and degradation.
2. Improve throughput and consistency compared to existing methods.

To solve this, we don’t just impose a “one-size-fits-all” recipe. We ask:

• What solvents are you using?
• How long does your current process take?
• What problems are you seeing?

The hard part isn’t the physics or chemistry—it’s understanding the client’s process and building enough trust so they share details honestly. Once we have that, we often co-develop a configuration or workflow with them. In a few cases, we’ve even created new product options in collaboration with customers.

Interviewer: What advice would you give chromatographers who are just starting to explore different sample preparation techniques?

Wade:
First, something slightly outside sample prep: check solvent miscibility. When I sold chromatography systems, I often saw people using solvent mixtures that would cause problems—locking up LC systems and creating all kinds of issues. Using miscibility charts can save a lot of pain.

For sample prep itself:

• Know your analyte: boiling point, reactivity, and stability.
• Choose your method based on sample sensitivity, solvent volatility, throughput, and budget.
• Don’t hesitate to leverage automation. Consultants and vendors are pushing it for a reason—it reduces manual workload, increases reproducibility, and actually improves job security by letting chemists focus on higher-value work like synthesis and method development.

Interviewer: You mentioned consultants. What resources or tools would you recommend for people doing research in this area?

Wade:
Many instrument companies—Shimadzu, Genevac, Büchi, and others—publish extensive application notes and host webinars. Those are great starting points.

There are also:

• Online learning platforms like Coursera (though not always sample-prep specific)
• Trade magazines and websites like LCGC, which cover chromatography fundamentals and advanced applications
• Professional organizations such as ACS for networking and technical resources
• Classic textbooks on instrumental analysis—many are still only in print, but they’re very solid
• Peer-reviewed articles and instrumentation forums

And just as important: talk to other scientists. Many chemists are quite private and hesitate to reach out, but networking can be extremely valuable.

Interviewer: We’ve talked a lot about automation already, but how do you see sample prep techniques evolving in the coming years?

Wade:
We’ll see more compact systems, but the big changes will be AI and automation playing a bigger role across the entire workflow.

I’ve already seen robots:

• Take samples off an RNA synthesizer
• Transfer them to an evaporation station
• Move dried samples into the next instrument

There are many micro-steps—cleaning glassware, labeling, reconstitution—where robots can help. Even eliminating one of those bottlenecks can improve throughput significantly.

Automation and AI will help:

• Streamline workflows
• Reduce human error (“person sitting in a chair” error, as I like to joke)
• Maintain compliance and traceability
• Let scientists focus on analysis and interpretation rather than repetitive manual tasks

Interviewer: In closing, is there anything else you’d like to share about the importance of sample prep in chromatography?

Wade:
I’d say: give sample prep the thought it deserves. Choosing the right technique doesn’t just help you reach your goals faster; it also opens up possibilities for more complex and innovative analyses.

Sample preparation is the foundation for reliable results. Ensuring consistency and optimizing your workflow are key to success in chromatography and analytical science in general.

This text has been automatically transcribed from a video presentation using AI technology. It may contain inaccuracies and is not guaranteed to be 100% correct.

Concentrating on Chromatography Podcast

Dive into the frontiers of chromatography, mass spectrometry, and sample preparation with host David Oliva. Each episode features candid conversations with leading researchers, industry innovators, and passionate scientists who are shaping the future of analytical chemistry. From decoding PFAS detection challenges to exploring the latest in AI-assisted liquid chromatography, this show uncovers practical workflows, sustainability breakthroughs, and the real-world impact of separation science. Whether you’re a chromatographer, lab professional, or researcher you'll discover inspiring content!

You can find Concentrating on Chromatography Podcast in podcast apps:

• Spotify
• Apple podcast
• podscan

and on YouTube channel