Job Title: Mass Spectrometry Scientist – Bioconjugate Therapeutics
Kelly® Science & Clinical is seeking a Mass Spectrometry Scientist – Bioconjugate Therapeutics for a direct hire opportunity with one of our clients, a stealth-mode biotechnology company in the Los Angeles, CA area. If you are driven by the prospect of translating cutting-edge scientific discoveries into tangible advancements and are poised to advance your career, join us as we pioneer progress in the biotechnology industry.

JOB SUMMARY:

A venture-backed biotechnology startup is seeking a detail-oriented and scientifically rigorous Mass Spectrometry Scientist to lead analytical characterization efforts for a growing pipeline of bioconjugate and antibody/peptide/oligo-based therapeutics. This role is critical to understanding conjugation efficiency, in vivo pharmacokinetics, and molecular identity across platforms. The successful candidate will initially collaborate with external CROs and instrumentation partners, with the opportunity to help establish internal mass spectrometry capabilities as the company scales.

Job Specifications:

• Job Type: Full-time, Direct Hire
• Location: Thousand Oaks, California
• Pay Rate: $95k-125k Depending on Experience

Roles and Responsibilities:

• Lead or support mass spectrometry-based QC of therapeutic conjugates using top-down proteomics, including intact mass confirmation and drug-to-antibody ratio (DAR) assessments.
• Perform and interpret bottom-up peptide mapping in collaboration with chemists and protein engineers.
• Analyze in vivo plasma and tissue samples to detect and quantify peptide or oligonucleotide species via LC-MS/MS, in partnership with CROs.
• Develop and standardize data processing and reporting pipelines to ensure analytical rigor and reproducibility.
• Serve as a technical liaison with external mass spectrometry providers and CROs, ensuring timely delivery, quality control, and method alignment.
• Contribute to the future build-out of internal mass spectrometry capabilities—including equipment selection, workflow design, and SOP development.
• Collaborate cross-functionally with chemistry, biology, in vivo, and CMC teams to ensure integrated data flow for decision-making.

Qualifications & Skills:

• Education: M.S. or Ph.D. in Analytical Chemistry, Biochemistry, Pharmaceutical Sciences, or related discipline.
• Experience:
• 2–5 years of experience with mass spectrometry, preferably in an industry setting focused on biologics, ADCs, or oligonucleotides.
• Hands-on experience in LC-MS/MS, especially for intact protein analysis, peptide mapping, and bioanalytical PK quantification.
• Familiarity with conjugation chemistry and its analytical implications.
• Proven ability to oversee external CROs and manage mass spectrometry workflows under time-sensitive timelines.
• Preferred Skills:
• Experience with oligonucleotide/peptide mass spectrometry or detection in plasma/tissue matrices.
• Background in bioconjugation, protein engineering, or organic synthesis.
• Proficiency in data analysis tools such as Xcalibur, MassLynx, Skyline, BioPharma Finder, or vendor-specific platforms.
• Familiarity with early-stage CMC analytical needs, including assay qualification.
• Knowledge of bioanalytical regulatory standards (e.g., GLP-like expectations for non-GLP studies).
• Comfortable navigating a startup environment with evolving infrastructure and high ownership expectations.

Opportunities:

• Take ownership of analytical development in a fast-paced, platform-driven startup.
• Help shape internal infrastructure and workflows for mass spectrometry.
• Collaborate with a multidisciplinary team to advance novel therapeutics.
• Contribute to the development of cutting-edge bioconjugate platforms with real-world therapeutic impact.

• Lead or support mass spectrometry-based QC of therapeutic conjugates using top-down proteomics, including intact mass confirmation and drug-to-antibody ratio (DAR) assessments.
• Perform and interpret bottom-up peptide mapping in collaboration with chemists and protein engineers.
• Analyze in vivo plasma and tissue samples to detect and quantify peptide or oligonucleotide species via LC-MS/MS, in partnership with CROs.
• Develop and standardize data processing and reporting pipelines to ensure analytical rigor and reproducibility.
• Serve as a technical liaison with external mass spectrometry providers and CROs, ensuring timely delivery, quality control, and method alignment.
• Contribute to the future build-out of internal mass spectrometry capabilities—including equipment selection, workflow design, and SOP development.
• Collaborate cross-functionally with chemistry, biology, in vivo, and CMC teams to ensure integrated data flow for decision-making