Your Resource For Cannabis Chemistry


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About Us

Our Team is a select group of experienced chemists and professionals that hold themselves and others to the highest quality and scientific standards. 

Our staff comes with extensive backgrounds working at both other cannabis labs and across many other scientific industries.Pacific Star Labs takes pride in only hiring the most competent team members, providing first-class training, and professional development opportunities.


Our Lab

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designed specifically to meet the rigorous testing requirements for cannabis in California. The lab is equipped with brand-new, top-of-line Shimadzu instrumentation. Our processes are optimized with a highly efficient workflow and superior quality control system. Combining these attributes with an exceptional, highly experienced staff enables us to deliver a best-in-class overall experience to our select group of partners.

Our Team of Experts

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David Winternheimer, PhD, PPM

General Manager

David has founded and advised more than 8 start-ups over the past decade in business development leadership positions, enabling many of them to achieve profitability and/or exit opportunities in their first years of operation. In addition to deep experience in sales/marketing, he also provides technical expertise to the team. David received his PhD in organic chemistry from UCLA and his Postdoctoral Professional Masters in Bioscience Management (PPM) from the Keck Graduate Institute of Applied Life Sciences.

James Borgese


James Borgese, BS

Lead Scientist & Lab Manager

James is one of the first chemists to have worked in heavy metal (ICP-MS) analysis in cannabis. As lead scientist, he is responsible for much of Pacific Star Labs’ method development/validation and continues to contribute to method optimization. James attended UC Berkeley and received his BS in chemical engineering from CSU Long Beach.

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Sheryl Silverman, BS

Microbiology & Quality Manager

Sheryl has over a decade of experience in research using PCR with a background in molecular genetics. She also has over 5 years of experience in managing ISO quality systems. As both microbiology and quality managers, she oversees microbial contamination testing and the full quality management system. Sheryl received her BA in chemistry with a minor in biology from Arcadia University.

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Tomas Garrett, BS, MBA


Tomas is an analytical chemist with years of chromatography experience in investigative analysis, cannabis testing, and food science. With a drive toward business development, Tomas earned his Executive MBA from UW-Milwaukee to combine his passion for science, with business in mind. He is committed to utilizing his unique background to improve the quality and efficiency of the cannabis testing industry.



Corinne Minzer, BS


Corinne is an analytical chemist with 8 years of experience in the pharmaceutical industry. She is well versed in instrumentation and documentation practices. She has a BS in Biochemistry/Chemistry from UC San Diego.

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Lucia Hernandez, BS

Microbiologist & Lab Technician

Lucia is well versed in ISO 17025 processes through her tenure working at Eurofins, a leading environmental testing lab in the USA. She supports the team from sample accession through analytical batch preparation. She received her BS in biology from CSULA.

Ajay Mistry


Ajay Mistry, BS

Lab Technician & Client Liaison

With over 5 years of small business background, Ajay supports the team in a multitude of ways. From assisting with laboratory work to customer service, Ajay helps oversee and coordinate efforts between all departments. He strives to provide exceptional customer service and has an exceptional passion for this industry.

Linda Chan


Linda Chan, BS


Linda has over two years of experience in research using aseptic cell culture techniques for MTT assays and glutathione quantification with a background in cancer metabolism. As a lab technician, she prepares samples for analysis, optimizes workflow, and identifies bottlenecks in sample preparation. Linda received her BS in Chemistry from CSUN.

Aaron Green


Aaron Green, PhD

Director of Business Development

Aaron manages business development activities at PSL, bringing 15+ years of experience in both chemistry and sales/marketing. Aaron received his PhD in chemistry from UCLA.

Kat Wilson


Kat Wilson

General Administration

Kat is an experienced administrator and office manager, helping several new companies establish themselves over the past decade. Kat supports all departments across the organization to ensure the company operates at optimal efficiency at all times.

RJ Fenske


RJ Fenske

Director of Marketing

RJ is an engagement specialist focused on people’s core needs, emotions and behavioral decisions. He brings an extensive background in digital media marketing and strategic development to improve user engagement across all mediums. He builds and nurtures the complex cross-functional groups through an ever evolving digital landscape. With a diverse background ranging from the entertainment industry, big pharma, biotech startups and health & wellness. He is devoted to enhancing global collaboration to empower better user experiences and accelerate the development of products that serve people's true needs.


We are always looking to add new talent to our growing team. Learn about open positions. 

Career Opportunities