Top 10 Questions for Sample Prep Technician Interview

1. What is the purpose of using a vortex mixer in sample preparation?

• To thoroughly mix samples and reagents
• To create a homogeneous solution or suspension
• To facilitate chemical reactions or enzymatic assays
• To extract or isolate analytes from samples

2. Describe the process of preparing a protein sample using a standard protocol.

Cell Lysis

• Harvest cells and wash them with PBS
• Resuspend cells in lysis buffer
• Homogenize cells using a sonicator or mechanical disruptor

Centrifugation

• Centrifuge the homogenate to separate cell debris from the supernatant
• Collect the supernatant containing the soluble proteins

Protein Quantification

• Determine the protein concentration using a Bradford assay or similar method
• Adjust the protein concentration to the desired level for downstream applications

3. What are the different types of chromatography techniques used in sample preparation?

• Size-exclusion chromatography (SEC)
• Ion-exchange chromatography (IEC)
• Affinity chromatography
• Reversed-phase chromatography (RPC)
• Hydrophobic interaction chromatography (HIC)

4. Explain the principles of liquid-liquid extraction and its applications in sample preparation.

• Separates analytes based on their solubility in different solvents
• Uses immiscible solvents to create two distinct phases
• Analytes partition between the phases based on their polarity and affinity for each solvent
• Applications: extracting organic compounds from aqueous samples, purifying lipids from biological samples

5. Describe the role of pH in sample preparation and how it affects the extraction efficiency of target analytes.

• pH can affect the solubility, ionization state, and stability of target analytes
• Optimal pH for extraction depends on the specific analyte and sample matrix
• pH adjustment can enhance extraction efficiency by improving analyte solubility or ionization
• Incorrect pH can lead to analyte loss, degradation, or interference from other components

6. What are the safety precautions that must be followed when working with hazardous chemicals in a sample preparation laboratory?

• Wear appropriate personal protective equipment (PPE), including gloves, lab coat, safety glasses, and mask
• Handle chemicals only in designated areas with proper ventilation
• Dispose of chemicals and waste according to established protocols
• Be aware of the potential hazards of each chemical and follow safety data sheets (SDS) strictly
• Have emergency response plans and equipment readily available

7. How do you maintain and calibrate laboratory equipment used in sample preparation?

• Follow manufacturer’s instructions for regular maintenance and calibration
• Use certified reference materials and standards for calibration
• Keep a logbook to document maintenance, calibration, and any repairs
• Troubleshoot and repair equipment when necessary
• Train laboratory personnel on proper use and maintenance of equipment

8. What is the importance of quality control (QC) in sample preparation and how do you ensure data integrity?

• QC ensures the accuracy, precision, and reliability of analytical results
• Involves using QC samples (e.g., blanks, standards, duplicates) to monitor performance
• Data integrity is maintained by following established protocols, documenting procedures, and reviewing results regularly
• QC helps identify and minimize errors, ensuring the validity of analytical data

9. How do you handle and store samples to maintain their integrity and prevent contamination?

• Use clean containers and materials to avoid contamination
• Label samples clearly and track their storage and handling
• Store samples at appropriate temperatures and conditions to preserve their stability
• Minimize exposure to light, heat, and other factors that could degrade samples
• Implement procedures to prevent cross-contamination and sample mix-ups

10. What are the challenges you have faced in sample preparation and how did you overcome them?

Candidates may provide specific examples of challenges they encountered, such as:

• Interfering substances in the sample matrix
• Low analyte concentrations
• Equipment malfunction
• Time constraints
• Describe the steps taken to address the challenge
• Explain how the issue was resolved or minimized
• Highlight the candidate’s problem-solving skills and adaptability

Sample Prep Technicians play a crucial role in the laboratory setting by preparing samples for analysis. Their responsibilities encompass:

1. Sample Collection and Preparation

Collecting and preparing samples from various sources, following established protocols to ensure accuracy and integrity.

• Collecting samples from patients, environmental sources, or industrial settings
• Preparing samples using techniques such as filtration, centrifugation, or extraction
• Maintaining detailed records of sample collection and preparation procedures

2. Quality Control

Ensuring the quality and integrity of samples throughout the preparation process.

• Performing quality control checks to verify sample stability and absence of contamination
• Following Good Laboratory Practices (GLP) and regulatory guidelines to maintain sample integrity
• Troubleshooting and resolving any issues that may arise during sample preparation

3. Equipment Operation and Maintenance

Operating and maintaining laboratory equipment used in sample preparation.

• Operating equipment such as centrifuges, spectrophotometers, and balances
• Performing routine maintenance and calibration of equipment to ensure accuracy and precision
• Troubleshooting and resolving equipment malfunctions

4. Data Management

Managing and recording data related to sample preparation and quality control.

• Documenting sample preparation procedures, quality control results, and equipment maintenance records
• Using laboratory information management systems (LIMS) to track and manage sample data
• Generating reports and presentations on sample preparation and quality control activities

To ace the interview for a Sample Prep Technician position, follow these preparation tips:

1. Research the company and position

Before the interview, thoroughly research the company and the specific position you are applying for. This will help you understand the company’s culture, values, and the specific responsibilities of the role.

• Visit the company’s website and social media pages to learn about their mission, products, and services.
• Review the job description carefully and make note of the key qualifications and requirements.

2. Practice answering common interview questions

Familiarize yourself with common interview questions and prepare your answers in advance. This will help you feel more confident and prepared during the interview.

• Prepare answers to questions about your technical skills, experience with sample preparation techniques, and knowledge of quality control procedures.
• Practice answering behavioral questions using the STAR method (Situation, Task, Action, Result).

3. Showcase your passion for science and detail

Sample preparation requires precision, accuracy, and a passion for science. Highlight these qualities in your interview by sharing examples of your attention to detail and your commitment to delivering high-quality results.

• Describe your previous experience with sample preparation techniques and how you ensured the accuracy and integrity of the samples.
• Discuss your understanding of quality control procedures and your commitment to following GLP guidelines.

4. Be prepared to discuss your teamwork and communication skills

Sample preparation technicians often work as part of a team and need to communicate effectively with other laboratory personnel. Be prepared to discuss your teamwork and communication skills in the interview.

• Share examples of how you have collaborated with others to achieve common goals.
• Highlight your ability to communicate clearly and effectively both verbally and in writing.

5. Bring a positive attitude and enthusiasm

A positive attitude and enthusiasm can go a long way in an interview. Show the interviewer that you are excited about the opportunity to join the team and contribute your skills.

• Smile, make eye contact, and be enthusiastic throughout the interview.
• Convey your interest in the position and the company’s mission.