Лако-красочные материалы — производство

The traditional method of essential oil analysis is to extract the plant material by steam distillation or with solvent and then fractionally distil the oil or extract and isolate individual components by chromato­graphic techniques for subsequent identification by spectroscopic methods. At each step the odour of the fractions and isolates is assessed and those with the desired characteristics are investigated further. To answer the enquiry about the key odour components of broom absolute, first a sample of the absolute that is of an acceptable odour quality is obtained. The absolute is the alcoholic extract of the concrete, which is itself the solvent extract of the flowers of Spartium junceum, Spanish broom, often referred to by its French name Genet. The odour of any natural extract can vary according to the geographical origin and quality of the plant material, the time of year it is harvested and the extraction method used. If no sample of adequate quality is commer­cially available then the fresh flowers would be obtained from the plant and the extraction carried out in the laboratory.

The first step towards separating the components of the absolute is fractional distillation. The absolute is distilled in the laboratory under vacuum, with a nitrogen blanket to reduce the risk of thermal degrada­tion of susceptible compounds. The individual fractions collected from the distillation are analysed by gas chromatography-mass spectro­metry (GC-MS) to determine their composition; some fractions might contain a single component while others may still be complex mixtures. Each fraction is assessed by a perfumer to determine which retained the odour most characteristic of the original material. The chosen fractions are analysed by GC-sniffing. If any of the individual components of the mixture are attributed with the characteristic odour that the perfumer requires, then work is directed at isolating and identifying these materials. If, however, the fraction is still too complex it is further fractionated by some form of liquid chromatography, such as flash
chromatography, and the sub-fractions are assessed by a perfumer and analysed by GC-MS and GC-sniffing.

If materials are found that have an interesting odour, but that cannot be identified by GC-MS, they are isolated by preparative techniques such as preparative high-performance liquid chromatography (HPLC) or preparative GC and their structures determined by nuclear magnetic resonance (NMR) which, in most cases, is able to provide an adequate identification. As the compositions of the chosen fractions and sub­fractions are determined, the perfumer tries to create an accord which adequately represents the odour of the original material by reconstruct­ing the fractions from their individual components.