The process of removing organics from a water sample and concentrating them in a solvent suitable for injection into the ______ is called ______.

• A. atomic absorption, liquid-phase microextraction
• B. atomic absorption, multiphase extraction
• C. mass spectrophotometer, solid-phase microextraction
• D. mass spectrophotometer, in situ microextraction

Answer: (C)

The concept being tested is choosing an extraction approach that both removes organic compounds from water and concentrates them into a small amount of solvent that can be injected into a mass spectrometric detector. Solid-phase microextraction uses a coated fiber to selectively adsorb organics from the water sample, providing a high enrichment in a tiny amount of extractant. The analytes can then be desorbed into a solvent (or directly into the instrument) for injection into the mass spectrometer, making it well suited for trace-level analysis of organics. Atomic absorption is used for metals and wouldn’t involve injecting into a mass spectrometer for organics, and the other extraction terms describe approaches that are less standard for preparing samples specifically for MS injection.