Top 10 Questions for Separations Scientist Interview

1. Explain the principles and instrumentation of Size Exclusion Chromatography (SEC)?

Size Exclusion Chromatography (SEC), also known as Gel Permeation Chromatography (GPC), is a technique used to separate molecules based on their size. The principle of SEC is that molecules are separated as they pass through a column packed with a porous gel. The pores in the gel are of different sizes, and molecules that are smaller than the pores will elute first, while larger molecules will elute later.

• The instrumentation of SEC consists of a column, a pump, a detector, and a data acquisition system.
• The column is packed with a porous gel, and the sample is injected into the column.
• The pump is used to move the sample through the column.
• The detector is used to detect the molecules as they elute from the column.
• The data acquisition system is used to collect and analyze the data.

2. Describe the different types of stationary phases used in High Performance Liquid Chromatography (HPLC)?

Normal Phase

• Silica gel
• Alumina
• Polystyrene-divinylbenzene (PS-DVB)

Reversed Phase

• C18
• C8
• Phenyl

Ion-Exchange

• Strong cation exchange (SCX)
• Weak cation exchange (WCX)
• Strong anion exchange (SAX)
• Weak anion exchange (WAX)

Size Exclusion

• Polystyrene
• Polyethylene glycol
• Polyacrylamide

3. How would you optimize the mobile phase for a given separation in HPLC?

The mobile phase is a critical component of HPLC, and its composition can have a significant impact on the separation. The following steps can be taken to optimize the mobile phase for a given separation:

• Choose the appropriate solvent system based on the solubility of the sample and the polarity of the stationary phase.
• Adjust the pH of the mobile phase to optimize the ionization of the sample.
• Add modifiers to the mobile phase to improve the separation, such as ion-pairing agents or complexing agents.
• Use gradient elution to improve the resolution of the separation.

4. What are the different types of detectors used in HPLC?

• UV/Vis detector
• Fluorescence detector
• Evaporative light scattering detector (ELSD)
• Refractive index detector (RID)
• Mass spectrometer (MS)

5. How would you troubleshoot a problem with a HPLC system?

Troubleshooting a HPLC system can be a complex process, but the following steps can be taken to help identify and resolve the problem:

• Check the system pressure and flow rate.
• Check the detector signal.
• Inspect the column for any leaks or damage.
• Check the mobile phase for any contamination.
• Restart the system and run a test sample.

6. What are the applications of HPLC in different industries?

• Pharmaceutical industry: Analysis of drugs and their impurities
• Chemical industry: Analysis of chemicals and their impurities
• Food industry: Analysis of food products and their contaminants
• Environmental industry: Analysis of environmental samples
• Forensic science: Analysis of evidence

7. Describe the different types of mass spectrometers used in proteomics?

• Quadrupole mass spectrometer
• Ion trap mass spectrometer
• Time-of-flight mass spectrometer
• Fourier transform ion cyclotron resonance mass spectrometer
• Orbitrap mass spectrometer

8. How would you prepare a protein sample for mass spectrometry analysis?

Preparing a protein sample for mass spectrometry analysis involves the following steps:

• Extract the protein from the sample.
• Digest the protein into peptides.
• Desalt the peptides.
• Concentrate the peptides.

9. What are the different types of data analysis methods used in proteomics?

• Database searching
• De novo sequencing
• Protein identification
• Protein quantification
• Protein-protein interaction analysis

10. How would you interpret a mass spectrometry data set from a proteomics experiment?

Interpreting a mass spectrometry data set from a proteomics experiment involves the following steps:

• Identify the proteins that were detected.
• Quantify the proteins that were detected.
• Analyze the protein-protein interactions that were detected.
• Draw conclusions about the biological system that was studied.

Separations Scientists are responsible for developing and optimizing separation processes to isolate and purify components from complex mixtures. Their work is essential in a wide range of industries, including pharmaceuticals, biotechnology, food, and environmental science.

1. Research and Development

Separations Scientists conduct research to develop new and improved separation methods. They also work to optimize existing processes to improve efficiency and reduce costs.

• Develop new separation methods for complex mixtures
• Optimize existing separation processes to improve efficiency and reduce costs

2. Process Design and Scale-up

Separations Scientists design and scale-up separation processes for commercial use. They work with engineers and other scientists to ensure that the processes are safe, efficient, and cost-effective.

• Design separation processes for commercial use
• Scale-up separation processes from lab to pilot to production

3. Troubleshooting and Problem Solving

Separations Scientists troubleshoot and solve problems that arise during the development and operation of separation processes. They use their knowledge of separation science to identify and resolve issues quickly and efficiently.

• Troubleshoot and solve problems that arise during the development and operation of separation processes
• Identify and resolve issues quickly and efficiently

4. Analytical and Experimental Techniques

Separations Scientists use a variety of analytical and experimental techniques to characterize and evaluate separation processes. These techniques include chromatography, spectroscopy, and mass spectrometry.

• Use a variety of analytical and experimental techniques to characterize and evaluate separation processes
• Chromatography, spectroscopy, and mass spectrometry

To prepare for your interview, research the company and the specific role you are applying for. Make sure you have a strong understanding of the key job responsibilities and how your skills and experience align with them.

1. Research the Company and the Role

Before your interview, take the time to research the company and the specific role you are applying for.

• Visit the company’s website to learn about their mission, values, and culture.
• Read the job description carefully and identify the key responsibilities and qualifications.
• Practice answering common interview questions based on the job description.

2. Highlight Your Skills and Experience

During your interview, be sure to highlight your skills and experience that are relevant to the role you are applying for.

• Use specific examples to demonstrate your abilities in research and development, process design and scale-up, troubleshooting and problem solving, and analytical and experimental techniques.
• Quantify your accomplishments whenever possible to show the impact of your work.
• Be prepared to discuss your experience with different separation methods and techniques.

3. Be Prepared to Answer Technical Questions

In addition to behavioral questions, you may also be asked technical questions about separation science during your interview.

• Be prepared to discuss your knowledge of different separation methods, such as chromatography, electrophoresis, and field-flow fractionation.
• You may also be asked about your experience with specific analytical techniques, such as mass spectrometry or spectroscopy.
• Practice answering technical questions in a clear and concise manner.

4. Ask Questions

At the end of your interview, be sure to ask questions of your own. This shows that you are engaged and interested in the role.

• Ask about the company’s culture and values.
• Inquire about the specific projects you would be working on.
• Ask about the opportunities for professional development and growth.