Chemistry - LC screening - polar NVOC
GC-MS captures volatile and semi-volatile compounds but misses an entire universe of extractables - polar non-volatile substances including polymer additives, degradation products, and high molecular weight contaminants require liquid chromatography for detection. Non-volatile organic compound screening through water extraction followed by LC-MS analysis identifies polar, non-volatile substances including polymer additives, degradation products, and high molecular weight contaminants that GC methods cannot detect due to thermal instability or insufficient volatility. Following ISO 10993-12 and 10993-18 protocols, this comprehensive approach captures substances requiring toxicological evaluation for complete safety assessment beyond what volatile screening provides. The LC-MS methodology enables detection of thermally labile compounds that decompose at GC injection temperatures, ionic species that don't volatilize, and high molecular weight substances exceeding GC capabilities - critical for biocompatibility evaluation demonstrating comprehensive chemical characterization. Applications include characterization of hydrophilic polymer devices where water-soluble components include oligomers and additives, identification of protein-based additives or biological contamination from manufacturing, and detection of non-volatile degradation products from biodegradable materials breaking down into polar fragments. For drug-device combinations, non-volatile polar extractables assessment proves critical because these compounds affect drug stability through chemical interactions or pH changes, potentially degrading active pharmaceutical ingredients. Hydrogel devices require comprehensive NVOC screening because high water content promotes migration of polar additives and degradation products directly contacting tissues. The water extraction simulates physiological exposure where body fluids solubilize polar compounds, while elevated temperature accelerates extraction representing extended clinical use or worst-case scenarios. The LC-MS analysis provides both identification through accurate mass measurement and fragmentation patterns, plus semi-quantitative data estimating exposure levels for toxicological evaluation per ISO 10993-17.