Identity determination and purity testing
Your substances, intermediates, or starting materials are analyzed with identity tests against qualified reference standards, quantitative, and limit tests.
Assays and impurity profiles are determined with high-performance liquid chromatography (HPLC) and gas chromatography (GC; GC-headspace).
The most important complemenatry method to chromatographic identity and purity determination is nuclear magnetic resonance (NMR) spectroscopy, in particular quantitative NMR (q-NMR) spectroscopy. A particularly quick method of confirming identity and polymorphism is FT–IR spectroscopy.
To test for ionic components, including common anions (chloride, bromide, phosphate, sulfate, nitrate) and cations (sodium, potassium, calcium, ammonium), ion chromatography (IC) is available.
Polymers are analyzed with gel permeation chromatography (GPC). Following the size exclusion principle, this technology allows the separation ofcomponents by molecular mass as well as the quantification of residual monomer.
Further confirmation of purity is obtained from loss on drying (LOD) and residue onignition (ROI) measurements. The latter is also known as the sulfated ashtest.
Water content is quantified by Karl-Fischer titration (KF) including coulometric KF titration.