In order to qualify, applicants must possess one year of specialized experience equivalent to at least the GS-10 (ZT-III at NIST) level. Specialized experience is defined as: Experience with characterization and value assignment of reference materials Experience with maintenance of, and analysis on liquid chromatography with mass spectrometry instrumentation (LC/MS) Experience in sample preparation for clinical materials and food materials. Experience with chemical inventory management systems Experience with balance verification using class 01 weights, including uncertainty estimation Experience refers to paid and unpaid experience, including volunteer work done through National Service programs (e.g., Peace Corps, AmeriCorps) and other organizations (e.g., professional; philanthropic; religious; spiritual; community, student, social). Volunteer work helps build critical competencies, knowledge, and skills and can provide valuable training and experience that translates directly to paid employment. You will receive credit for all qualifying experience, including volunteer experience. The qualification requirements in this vacancy announcement are based on the U.S. Office of Personnel Management (OPM) Qualification Standards Handbook. If requesting reconsideration of your qualification determination, please refer to the following site: Applicant Reconsideration