Principal Scientist, Analytical Chemistry

We are a stealth-stage, Series A–funded biotech in Cambridge, MA, developing next-generation antibody-drug conjugates for oncology. As an early member of a small, highly collaborative team, you will help shape our analytical capabilities from the ground up, with direct influence on programs advancing toward the clinic.

Position Summary

We are seeking an experienced analytical scientist with deep, hands-on ADC expertise to lead LC-MS-based characterization and bioanalytical quantitation across our discovery and early development portfolio. This is a senior individual contributor role that combines bench work with scientific leadership. You will own analytical strategy for our programs, serve as the company's go-to ADC analytical expert, and play a central role in building out our lab.

The level (Senior Scientist, Principal Scientist, or Senior Principal Scientist) will depend on experience.

Key Responsibilities

• Lead analytical characterization of ADCs, antibodies, and small-molecule linker-payloads using LC-MS and HPLC, including intact, deglycosylated, and reduced mass analysis; DAR determination and drug-load distribution; and SEC, HIC, and RP-HPLC methods.
• Develop and run bioanalytical assays from plasma, serum, and tissue, including total antibody, conjugated payload, and free payload quantitation, in vivo DAR over time, and plasma stability studies.
• Identify and characterize ADC catabolites and metabolites from in vitro and in vivo studies using affinity capture, forced payload release, MS/MS, and SIM/targeted MS.
• Develop, optimize, qualify, and troubleshoot analytical methods, and support method transfer to CROs and CDMOs as programs advance.
• Define analytical and bioanalytical strategy for ADC programs and serve as the analytical representative on cross-functional project teams.
• Select and oversee CROs and CDMOs for analytical and bioanalytical work, and review their data and reports.
• Lead the design and buildout of internal analytical capabilities, including instrument selection, workflow design, and data systems, as the company scales.
• Operate, maintain, and troubleshoot instrumentation such as Orbitrap and single-quad LC-MS, UHPLC/HPLC, and UV-Vis systems.
• Provide technical leadership across the organization, guiding cross-functional decisions on conjugation strategy, candidate selection, and develop ability.
• Document work in ELNs, maintain analytical data, and prepare technical reports and presentations.

Required Qualifications

• Ph.D. in analytical chemistry, biochemistry, or a related field with 5+ years of industry experience (Senior Scientist), 8+ years (Principal Scientist), or 12+ years (Senior Principal Scientist). Candidates with an M.S. or B.S. and equivalent experience will be considered.
• At least 3 years of hands-on ADC analytical experience in the biopharmaceutical industry.
• Deep expertise in LC-MS characterization of antibodies and bioconjugates, including intact and reduced mass analysis and DAR determination.
• Strong working knowledge of SEC, HIC, and RP-HPLC for ADCs.
• Experience with protein sample preparation, including deglycosylation, reduction, and enzymatic digestion.
• Understanding of conjugation chemistries (cysteine, lysine, and/or site-specific) and linker-payload stability.
• Hands-on experience maintaining and troubleshooting LC-MS and HPLC systems.
• Clear communication skills and a track record of influencing chemists, protein engineers, and biologists on cross-functional teams.
• Comfort working independently with shifting priorities in a fast-paced, early-stage setting.

Preferred Qualifications

• Experience with ADC bioanalysis supporting PK/TK studies, including hybrid LBA-LC/MS.
• Peptide mapping and conjugation site analysis.
• Experience supporting IND-enabling studies or transferring methods to GLP/GMP environments.
• Experience managing CROs and CDMOs.
• Experience helping build or scale an analytical lab at an early-stage company.
• Peer-reviewed publications or presentations in ADC or protein analytics.

atida bio is an equal opportunity employer. We evaluate all qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, veteran status or any other characteristic protected by applicable law.