Organic and organo-metallic substances

Simple cases such as those encountered in the field of metals and other inorganic substances are rarely encountered for organic substances. In this case the detection problem of impurities is double. First the impurities are more difficult to be identified 

When the product is purified, its identity is established by H NMR, IR, FAB-MS, etc. An elemental analysis associated with a fusion point determination by thermo-gravimetric methods helps to establish the identity of the substance and its stoichiometry. Then the product is analysed on various GC and HPLC phases with various detectors. Impurities are often present in amounts that do not allow H NMR identification. 

When identification is done, the mass fraction of the substance in the material can be studied. Detection by FID and some forms of MS allow reaching a mass proportional response and establishing a quantified link between signal, mass of product and impurity. ECD allows the presence of heteroatoms, e.g. halogens, to be revealed. HPLC may reveal the presence of a substance that is not accessible by GC. Atomic spectrometry, as used for the purity of inorganic substances, can help to determine the amount of metal in an organo-metallic substance and the presence of some metals or metalloids. 

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