Fragrance concentrate

Supercritical C02 extraction coupled with a fractional separation technique is used by producers of flavours and fragrances to separate and purify volatile flavour and fragrance concentrates. Like any solvent, supercritical C02, it allows processing chemicals by predpita-tion or recrystallisation, obtaining partides of controlled size and shape, without excessive fines without thermal stresses and controlling the shape of a polymorphic substance. 

TABLE 1.2 Upper Limit Fragrance Concentrations in Various Personal Care Products... 

Production. Essential oils are obtained from plant materials by distillation with water or steam. After condensation of the vapor phase, the oil separates from the aqueous phase and is removed. The yield of essential oil, based on the starting plant material, generally ranges from a few tenths of 1 % to a few percent. The apparatus used in the production of natural fragrance concentrates is described in [223]. 

Nature of branded fragrance % fragrance concentrate in ethanol Alcohol specification (% in water)... 

Chung, S.L., Tan, C.-T., Tuhill, I.M., and Scharpf, L.G. 1994. Transparent oil-in-water microemulsion flavor or fragrance concentrate, process for preparing same, mouthwash or perfume composition containing said transparent microemulsion concentrate, and process for preparing same. U.S. Patent 5283056, filed July 1, 1993, and issued Feb. 1, 1994. 

The history of the expression of essential oils from the epicarp of citrus fruits is not nearly as interesting as that of hydrodistillation. This can be attributed to the fact that these expressed fragrance concentrates were more readily available in antiquity as expression could be effected by implements made of wood or stone. The chief requirement for this method was manpower, and that was available in unlimited amount. The growth of the industry led to the invention of new mechanical machinery, followed by automation and reduction of manpower. But this topic will be dealt with later on. 

The SIM approach was fully reconsidered by the International Fragrance Association (IFRA), which proposed a method that can be used as a reference in the laboratories of the fragrance industry to determine PASs in fragrance concentrates (IFRA, 2003 Chaintreau et al, 2003). The GC separation was optimized and three ions per analyte were used to help identify the analyte one of them for quantification, and the other two as qualifiers. For a compound eluting in the expected, pre-defined retention window, its identity is checked by comparing its ion abundance ratios with those of a reference compound using the value Q (see equation 6.2.1). When its value is at least equal to 90, the analyte is considered as being positively identified. 

Three PAS-free fragrance concentrates of increasing complexity (32, 57 and 168 constituents) were spiked with five compounds randomly selected from the list of 24 PASs (see Table 6.2.2). The mean recovery, calculated from the results in Table 6.2.2, was 100.5%, with a coefficient of variation of 16%. Some peaks with Q values below 90 and eluting in the expected PASs time windows required confirmation in scan mode to confirm their presence. Moreover, linalool and benzyl benzoate were over-evaluated in the most complex sample, due to co-elution of isobaric ions. Thus, although in general terms the method provides good results, the aforementioned problem of co-elution may stiU occur. 

Quantification of three PAS-free spiked fragrance concentrates by using a GC-MS(EI) SIM approach with three ions per compound (adapted from Chaintreau et al, 2003)... 

Results obtained by GC-MS in El and Cl ionization modes, and GCXGC-FID and GCXGC-MS(EI) strategies, in the analysis of a PAS-free fragrance concentrate containing 168 ingredients spiked with five PASs at individnal levels of 50 mg/kg (adapted from Debonneville et ai, 2004)... 

A complex PAS-free fragrance concentrate (containing 168 ingredients) spiked with five PASs was analysed by using GC-MS (Cl). Results are shown in Table 6.2.4, and compared with those obtained by using the routine IFRA method (i.e. GC-MS (El)). As can be seen, linalool and anise alcohol, which could not be determined accurately using the El mode due to co-elutions, were satisfactorily evaluated by the Cl mode. This shows that this technique provides an alternative to the El method, when the latter fails to determine a co-eluted analyte in complex samples. However, its routine application is limited by the stability of the Cl source pressure that requires frequent calibrations. 

Figure 6.2.5 Contour-plot resulting from the GCXGC-MS(EI) analysis of a PAS-free fragrance concentrate containing 168 constituents spiked with five PASs at a level of 50 mg/L. (1) Linalool, (2) anise alcohol, (3) eugenol, (4) alpha-isomethyl ionone, and (5) benzyl benzoate (from Debonneville et al., 2004).

Although no sample pre-treatment is required for volatile samples such as fragrance concentrates and perfumes, some problans of inaccuracy might occur after several injections as previously mentioned, due to the accumulation of low-volatile compounds in the injector (Chaintreau et al, 2003). Obviously, other cosmetic products with lower volatility will promote this problem. AU this implies that the direct injection of a solvent extract from cosmetics is not viable, because traces of the matrix are co-extracted and then rapidly pollute the GC injectors. 

When there is no concern about the matrix (fragrance concentrates and extracts, alcoholic perfumery) the complexity lies in the huge number of perfume constituents, which may interfere with PASs. GC with MS detection in SIM mode gives the most satisfactory results for routine determination. Among more sophisticated multidimensional approaches, GC-MS/MS lowers possible false positives and negatives, whereas... 

P. is a dilution of a - fragrance in alcohol and water, destined to be applied on the skin. Depending on the fragrance concentration level in the formula, the product will be called p. or extrait (15-30%), Eau de Toilette (8-15%) or Eau de Cologne (<8%). In men s perfumes, Eau de Toilette and after-shave are produced. After-shave is equivalent to Cologne in concentration. 

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