REACH-driven developments in analysis and physicochemistry.

The enforcement of the REACH regulation in the fragrance domain has created new challenges for the analytical and physical chemist. Many chemicals used as perfumery ingredients are hydrophobic, because low-polar compounds exhibit a higher substantivity (i.e. persistence after application) than do polar compounds. As a result, the usual protocols are often unsuitable and new methods must be developed. Biodegradation studies sometimes call for the quantifi cation of traces of such hydrophobic analytes in complex media (e.g. waste water, aqueous surfactant solutions). Existing sample preparation techniques are either ineffi cient or time consuming. A new approach is proposed, based on single-use absorbants, which allows accurate quantifi cation down to the 100 ppb range. This extremely simple technique allows good throughput analyses. Determining the environmental profi le of a compound requires the determination of some physical constants. Among these, solubility in water can be obtained from theoretical models or experimentally, but the resulting values may greatly diff er as a function of the model or the protocol. Several experimental approaches are critically discussed and compared with a refer- ence technique. The air-to-water partition coeffi cients are determined by using an improved version of the previously devel- oped static-and-trapped headspace technique. Copyright © 2009 John Wiley & Sons, Ltd. hydrophobic compounds in the presence of surfactants and in the measurement of physical constants. Each of these topics will be later reported in detail in separate papers. Two compounds, Cetalox® and Polysantol,® are used here to illustrate these devel- opments, as they are important constituents of compounded fragrances. They are representative of the amber and sandal- wood families, respectively, and both are hydrophobic.