Measurement Science to Advance Understanding of Chemical Equilibria in Natural Waters

Measurement Science to Advance Understanding of Chemical Equilibria in Natural Waters

NIST only participates in the February and August reviews.

NIST has a long-standing program in electroanalytical chemistry which provides certified reference materials for pH and acidimetric measurements. We are recruiting applicants to advance our electrochemistry reference materials program to support the development of novel instrumentation and reference procedures for the determination of chemical equilibria in natural waters. Research topics include (1) the development of instrumentation and procedures to determine the carbon dioxide system in seawater using methods such as total alkalinity, total dissolved inorganic carbon, and spectrophotometric pH, (2) evaluation of synthetic solutions to measure ion fitting parameters to improve thermodynamic models of aqueous solutions, (3) development and use of manometry or other methods to determine total dissolved inorganic carbon and partial pressure of aqueous carbon dioxide, (4) assessment of traceability and uncertainty budgets for existing and newer methods to examine aqueous equilibrium. The goal of NIST’s ongoing effort with water quality is to provide reference materials and standards for use by coastal, estuarine, and open ocean researchers that will improve the ability to model chemical equilibrium within aquatic systems. We are seeking independent and motivated individuals with excellent communication skills and backgrounds in electrochemistry, analytical chemistry, chemical oceanography, and other related fields to contribute to these collaborative, interdisciplinary projects. Facilities include primary pH electrochemical cells, coulometric titrators, electrometric titration systems, an ion chromatograph, and an absorbance spectrophotometer. Applicants should work with the advisor to develop independent research projects within the scope of the research area described in this opportunity.

REFERENCES

Simon L. Clegg, Jason F. Waters, David R. Turner, and Andrew G. Dickson. (2023) Chemical speciation models based upon the Pitzer activity coefficient equations, including the propagation of uncertainties. III. Seawater from the freezing point to 45?°C, including acid-base equilibria. Marine Chemistry, 250, https://doi.org/10.1016/j.marchem.2022.104196 .

B. R. Carter, J.Sharp, A. Dickson, M. Alvarez, M. Fong, M. García-Ibáñez, R.Woosley, Y.Takeshita, L.Barbero, R. Byrne, W.-J. Cai, M. Chierici, S. Clegg, R.Easley, A. Fassbender, K. Fleger, X. Li, M. Martín-Mayor, K.Schockman, Z. Wang. (2024) Uncertainty sources for measurable ocean carbonate chemistry variables. Limnology and Oceanography, 69: 1 – 21. https://doi.org/10.1002/lno.12477 .

M. Fong, Y. Takeshita, R. Easley, J. Waters. (2024) Detection of impurities in m-cresol purple with SIMCA for the quality control of spectrophotometric pH measurements in seawater. Marine Chemistry, 259: 104362. https://doi.org/10.1016/j.marchem.2024.104362 .

analytical chemistry; marine chemistry; carbon dioxide; uncertainty quantification; experimental measurements; pH; spectrophotometry; water quality; electrochemistry

Citizenship:  Open to U.S. citizens