Quantitative determination of product yields

Initial analyses ofproduct mixtures canbe carried out by GC-MS, LC-MS or NMR. Using GC orLC, components present in very small amounts ( 1%) can be identified. MS is very useful for the analysis of mixtures of known compounds, but usually does not provide sufficient information on which to base structural assignments for new compounds. Because of the 

More accurate quantitative analyses can be carried out by GC or LC. A suitable internal standard is usually required it must be chemically stable and involatile under the conditions of the experiment (prior to injection into the chromatography apparatus), and must be resolved from the other signals in the chromatogram. It is usually added to the product mixture after the reaction has been completed but before any extraction, purification or analysis steps are undertaken. Saturated hydrocarbons of Cio or above are typically used as internal standards for GC [7]. Response factors are obtained for each component of 

The yield and purity of each product depend in part on competing reactions, which can be investigated by the methods discussed below. Other important aspects are methods of purification or extraction and the required specification of product purity. 

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