Tackling the extended list of fragrance allergens by flow-modulated GC×GC–TOF MS/FID

This preliminary study investigates the use of flow-modulated GC×GC to analyse an 84-component allergen calibration standard, with simultaneous detection by TOF MS for confident identification and FID for robust quantitation. A high degree of linearity and repeatability is demonstrated, showing that flow-modulated GC×GC is a promising approach for high-throughput quality control of fragranced products. The validity of the GC×GC–TOF MS/FID method is then demonstrated with the examples of essential oils and a fragrance mix.

Introduction

In 2003, an EU Directive[1] restricting the use of allergenic compounds in fragrances was released. The Directive named a total of 26 allergens, stating that they should be labelled if present at >100 ppm in ‘wash-off’ products (such as shower gels), or >10 ppm in ‘leave-on’ products (such as perfumes).

Compliance with this Directive therefore requires that these compounds are identified and quantified accurately, which is a considerable challenge due to the complex matrix and wide concentration ranges involved.[2]

Currently, this necessitates the use of different stationary phases to achieve the required chromatographic resolution for each target compound, making it a laborious process.[3] Given the proposal to expand the list of monitored allergens to over 80 individual compounds,[4] this process will only become more demanding.

To tackle this issue, the fragrance industry has turned to comprehensive twodimensional GC coupled with time-of-flight mass spectrometry (GC×GC–TOF MS).[5] The enhanced separation capacity copes with the most complex of matrices, while the commercialisation of simple, consumable-free flow modulation devices has made routine use more feasible.