CWEA Grade 3 Lab Analyst Practice Exam

The technique of extraction is utilized to isolate anionic surfactants from the sample matrix because it efficiently separates these compounds based on their solubility in different solvents. In the extraction process, a solvent is chosen that selectively dissolves the anionic surfactants while leaving behind less soluble components of the matrix. This allows for a concentrated solution of the target compounds to be obtained, which can then be analyzed further.

Extraction methods can vary, but common techniques include liquid-liquid extraction and solid-phase extraction. These methods exploit the chemical properties of anionic surfactants, such as their affinity for polar solvents, to separate them from other substances in the sample. This is particularly important in environmental and wastewater analysis, where anionic surfactants can be present in complex matrices alongside various other contaminants.

Other techniques like filtration, evaporation, and distillation are not suitable for isolating anionic surfactants from a mixture. For instance, filtration is used for separating solids from liquids but does not target specific chemical compounds. Evaporation and distillation rely on differences in boiling points, which may not effectively isolate anionic surfactants given that many compounds can have similar boiling points or may decompose during the process. Thus, extraction stands out as the preferred