Yowei Therapeutics is seeking a Senior Scientist to own LC-MS/MS for regulated bioanalytical testing in support of pharmacokinetic (PK) studies for the company's peptide clinical programs. This is a hands-on, single-owner role responsible for the full method lifecycle - development and validation. Core duties are included below. Job Duties: • Develop, qualify, and validate LC-MS/MS bioanalytical methods for quantitation of peptide therapeutics and, where required, their metabolites in biological matrices (plasma, serum, tissue) to support nonclinical and clinical PK studies. • Execute full bioanalytical method validation to ICH M10 - selectivity, specificity, calibration curve and range, within- and between-run accuracy and precision, matrix effect and recovery, carryover, dilution integrity, and the complete stability panel (stock/working solution, benchtop, freeze-thaw, processed/autosampler, and long-term matrix stability). • Design and manage study sample analysis runs, including run acceptance criteria, calibration and QC schemes, reassay rules, and incurred sample reanalysis (ISR). • Establish fit-for-purpose peptide sample preparation - protein precipitation, solid-phase extraction, and hybrid immunocapture-LC-MS/MS where sensitivity demands - using stable-isotope-labeled internal standards and surrogate-peptide (signature peptide) strategies as appropriate. • Address peptide-specific bioanalytical challenges, including non-specific/adsorptive loss, protease-driven instability, and quantitation of endogenous or endogenous-like peptides (e.g., thymosin -class analytes) requiring surrogate-matrix or authentic-matrix background-subtraction approaches. • Author bioanalytical validation protocols, validation reports, study analytical plans, and the corresponding sections of regulatory submissions. Requirements • Ph.D. in analytical chemistry, biochemistry, or a related field with 4-7 years of hands-on LC-MS/MS experience; or M.S./B.S. with 8-12 years of experience in GLP laboratory environments and GMP environments. • Demonstrated, hands-on expertise in developing and validating LC-MS/MS bioanalytical methods for quantitation of peptides or other biologics in biological matrices (e.g., plasma, serum) to support PK studies. • Direct, hands-on experience with regulated bioanalytical method validation and study sample analysis under ICH M10 (and/or the FDA Bioanalytical Method Validation guidance) in support of PK studies. • Strong working knowledge of GLP (21 CFR Part 58) as applied to nonclinical PK/bioanalytical studies, GCLP principles as applied to clinical-phase human sample analysis, 21 CFR Part 11 (data integrity), ICH Q2(R2), and ICH M10. • Proven ability to author validation protocols/reports and submission-ready analytical documentation, and to lead OOS/OOT investigations. • Ability to work independently as the sole MS owner while collaborating across CMC, QA, and clinical functions. Benefits • Medical, dental, and vision insurance (Kaiser HMO or BlueShield PPO. Employer pays 85% for Employee and 50% for Employee's family; Dental: Aetna Dental, Delta Dental, Guardian Dental, MetLife Dental. Vision: VSP and Aetna EyeMed) • Basic life ($20,000 paid by company) and supplemental life insurance (optional supplemental). • Disability insurance 50% standard employer paid. • 401k 10% 1:1 match • PTO policy. 10 days PTO • Companywide paid holiday during: Week of July 4, Thanksgiving (2 days), Week of December 25 • Carpool, clean air vehicle, and cell phone reimbursement • Employee rewards and recognition program • Company organized social events • Quarterly sponsored team building activities