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The performance of HPLC-UV as a means of quantifying selected furocoumarins in essential oils has been evaluated, based on a ring test validation approach. Accuracy profiles were generated, to determine bias and statistical confidence associated with determination at different concentrations, along with lower limits of quantification (LOQ). From these findings, it can be concluded that the method described may only be used in simple cases (essential oils), to measure individual furocoumarin compounds at concentrations greater than 10mg/l; the non compound-specific nature of detection by absorption in the UV range is unable to overcome the effect of interferences arising from chromatographic coelutions, such as those encountered in the analysis of complex commercial fragrance mixtures. The use of an algorithmically calculated 'spectral similarity' function, with reference to authentic standards, may be used to improve reliability in assignment and quantification.

Previous publications investigated different data treatment strategies for quantification of volatile suspected allergens by GC/MS. This publication presents the validation results obtained on “ready to inject” samples under reproducibility conditions following inter-laboratory ring-testing. The approach is based on the monitoring of three selected ions per analyte using two different GC capillary columns. To aid the analysts a decisional tree is used for guidance during the interpretation of the analytical results. The method is evaluated using a fragrance oil concentrate spiked with all suspected allergens to mimic the difficulty of a real sample extract or perfume oil. At the concentrations of 10 and 100 mg/kg, imposed by Directive 76/768/EEC for labeling of leave-on and rinse-off cosmetics, the mean bias is +14% and −4%, respectively. The method is linear for all analytes, and the prediction intervals for each analyte have been determined. To speed up the analyst's task, an automated data treatment is also proposed. The method mean bias is slightly shifted towards negative values, but the method prediction intervals are close to that resulting from the decisional tree.

Commercial interfaces for multidimensional gas chromatography (MDGC) are based either on a valve or a pneumatic switching between columns. Both exhibit significant drawbacks and only few suppliers exist. An extremely simple interface has been set up to overcome these limitations without requiring any pneumatic control or valves switching. This new MDGC design is based on the cryo-control of the analyte transfer from the first to the second column through two cool strands of a capillary. This technique is simple to implement and does not require any special column connections. Applications involve non-polar/polar phase combinations, as well as chiral analysis, hyphenation to a conventional mass spectrometer, and olfactometric detection. In contrast to conventional MDGC configuration, the present configuration allows the use of a single oven to operate both columns at different temperatures.

The European legislation requires that fragranced products are evaluated for their content in 24 compounds that are suspected to be skin sensitizers. Their quantitation in fragrance concentrates may not be achieved with GC-flame ionization detection (FID), due to the complexity of these mixtures and even comprehensive GC-FID does not provide sufficient resolution. This paper reports the first example of quantitation based on the hyphenation of comprehensive GC with a low-cost quadrupole MS. A detection frequency of 30.7 Hz can be obtained by monitoring a single ion. This allows a satisfactory evaluation of the area sum over the 2-3 modulations of a given compound and linear calibration curves are obtained. Analyses are completed within 35 min.

The simultaneous distillation—extraction (SDE) system developed by Likens and Nickerson (ASBC Proceedings, 1964, p. 5) and modified by Godefroot, Sandra and Verzele [J. Chromatogr., 203 (1981) 325] is one of the most popular methods currently used to isolate volatile components from a matrix prior to gas chromatographic analysis. Since it leads to a thermal generation of artefacts, the device has been improved in the present work to allow isolation between 20 and 40°C under vacuum. The system was closed and made airtight by means of a valve under static vacuum to avoid volatile losses. These conditions require the use of solvents with a boiling point close to that of water and the temperature must be electronically regulated. The absence of artefact generation was tested with linalyl acetate, honey and a Maillard model reaction. The recovery yields of classical SDE and SDE under vacuum were found to be similar.