Preservation products decomposition phases

Freezing samples or initially filtering liquids can reduce these problems. In the absence of freezing, a preservative should be added to prevent decomposition of biota and accumulation of decomposition products. The analyst should plan to minimize the problem by prompt analysis and either mix the sample before taking an aliquot or sample the liquid and solid phases in proportion. 

We devote this chapter to a brief review of the major types of solid catalysts used in the production of intermediates and fine chemicals. Though these reactions can be carried out in both the vapor and liquid phases, the substrates used in organic synthesis are often relatively complex liquid molecules which tend to decompose under harsh conditions. Hence it is usually desirable to operate under softer conditions, thus preserving the liquid state of the substrate and preventing any likely decomposition to unwanted products. 

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