impuriti

Impurities are substances that are present in a material but are not part of its intended composition. They can alter physical properties, stability, taste, safety, or performance. Impurities may occur at trace levels or in larger amounts and are often classified as organic, inorganic, or elemental (metallic). They can be intrinsic to the material, arising from incomplete reactions or degradation, or introduced through contamination during production, handling, or storage. In electronics, dopants and residual impurities influence conductivity and reliability.

Common sources include starting materials, solvents, catalysts, water, packaging, process equipment, and environmental exposure. Biological materials may carry contaminants such as microbes or particulates. Over time, impurities can form through chemical reactions, hydrolysis, oxidation, or microbial growth.

Detecting and quantifying impurities relies on analytical techniques such as chromatography (HPLC, GC), spectroscopy (UV-Vis, IR, NIR), mass spectrometry, atomic absorption or emission methods, and other instrumental methods. Sensitivity and selectivity depend on the matrix and regulatory requirements. Impurity profiling supports quality control, safety assessment, and compliance with standards.

Control strategies include purification and separation steps (distillation, crystallization, filtration, chromatography), refining of starting materials, purification of solvents, and good manufacturing practices. In pharmaceuticals and food, impurities are subject to regulatory thresholds and reporting requirements, as low as required for safety and efficacy. Understanding impurity profiles helps predict shelf life, compatibility, and performance of products.