original_query: What are some spectroscopic methods that can be used to measure the concentration of CAS?
query: What are some spectroscopic methods that can be used to measure the concentration of carbonate-associated sulfate (CAS)?
answer: Spectroscopic methods for measuring CAS concentration include X-ray-induced fluorescence of sulfur, oxygen, carbon, and other elements to determine abundance and ratios, or using the energy spectrum of an electron beam transmitted through the sample.