Sample Preparation Mastery: Evaporation Techniques for Chromatography

Sample Preparation Techniques: Insights from Industry Expert Wade Hasenour

In a recent interview, David Oliva, General Manager of Organomation, sat down with Wade Hasenour, Regional Sales Manager at Genevac, to discuss sample preparation techniques for chromatography. With his extensive background in biochemistry and experience in various laboratory roles, Hasenour provided valuable insights into the world of sample evaporation and preparation.

The Evolution of Sample Preparation

Hasenour noted that one of the most significant changes in sample preparation has been the increased focus on robotics and automation. This shift is driven by the need to improve workflow efficiency, reduce production time, and minimize human exposure to chemicals. As Oliva put it, "Time is money," especially in commercial labs.

Key Sample Concentration Techniques

Rotary Evaporation

Rotary evaporation is a traditional method that uses gentle heating through water. It's particularly effective for:

- APIs (Active Pharmaceutical Ingredients)
- Organic synthesis
- Low boiling point solvents

Advantages:
- Quick and easy for single samples
- Efficient for low boiling point solvents

Limitations:
- Can only process one sample at a time
- May compromise delicate samples at higher temperatures

Centrifugal Evaporation

This technique combines vacuum technology with centrifugal force, making it ideal for:

- High-throughput drug screening
- RNA therapeutics
- Oligonucleotide synthesis
- Diagnostic reagent kits

Advantages:
- Can process multiple samples simultaneously
- Gentler on temperature-sensitive compounds
- Effective for harsh solvents like DMSO

Limitations:
- Takes longer than rotary evaporation for a single sample

Freeze Drying

Freeze drying, or lyophilization, is best suited for:

- Biological samples
- Peptides
- Analytes requiring long-term stability

Advantages:
- Preserves sample structure
- Enhances shelf life
- Can handle various sample formats (trays, vials, flasks)

Nitrogen Blowdown

Nitrogen blowdown is a simple yet effective technique for sample concentration and solvent evaporation. It is particularly useful for:

Advantages:

Nitrogen blowdown works by directing a stream of nitrogen gas onto the surface of a liquid sample. The gas flow promotes evaporation by constantly removing the vapor above the liquid, while also preventing oxidation of sensitive compounds. This technique is often used as a final step in sample preparation to achieve precise volumes or complete dryness

Choosing the Right Technique

When selecting a sample preparation method, Hasenour emphasizes considering several factors:

1. Cost-effectiveness: Budget constraints often dictate available options.
2. Sample integrity: Temperature-sensitive compounds may require gentler techniques.
3. Efficiency: Consider the number of samples and processing time required.
4. Solvent types: Some techniques handle certain solvents better than others.

Challenges and Solutions

Hasenour highlighted common challenges in sample preparation, including:

- Cross-contamination in well plates
- Difficulty in evaporating high boiling point solvents like DMSO
- Preventing sample degradation

To address these issues, systems have been developed with features like inert gas purging and anti-bumping technology.

The Future of Sample Preparation

Looking ahead, Hasenour predicts that AI and automation will play an increasingly significant role in sample preparation. He envisions more compact systems and robots handling various aspects of the workflow, from sample transfer to evaporation and reconstitution. This shift towards automation is expected to:

- Streamline workflows
- Reduce human error
- Improve consistency and reliability
- Allow scientists to focus on more complex aspects of their work

Conclusion

As sample preparation continues to evolve, it remains a critical foundation for reliable chromatography outcomes. By choosing the right technique and embracing automation, chromatographers can optimize their workflows, achieve faster results, and open doors to more complex analyses. As Wade Hasenour aptly puts it, "Sample prep is literally just consistency and reliability."

For those looking to expand their knowledge in this area, Hasenour recommends leveraging resources such as application notes from equipment manufacturers, online platforms like Coursera, and professional organizations like ACS. He also encourages chromatographers to network and share knowledge with peers, emphasizing the value of collaboration in advancing the field.