The fragrant terpenes limonene and linalool can form skin sensitizing hydroperoxides upon prolonged exposure to air. Recently, high frequencies of positive patch tests to oxidized linalool and limonene were reported from multiple dermatological centres. However, there is a lack of data indicating potential sources of consumer exposure to sensitizing doses of terpene hydroperoxides which explains this frequent contact allergy. Within the IDEA project (International Dialogue for the Evaluation of Allergens; http://ideaproject.info/), a taskforce was formed to drive analytical method development and evaluation. In an inter‐laboratory study in five laboratories, a method based on hydroperoxide reduction combined with GC–MS was tested for reproducibility. Blinded samples of commercial fine fragrances were spiked with four different hydroperoxides. In samples spiked with 100–200 μg/ml, an average recovery of 86–105% with a relative standard deviation between laboratories of 7.4–22% was found. In samples spiked with 20–50 μg/ml, the recovery was 85–91%. The reduction approach offers a transferable and reproducible method to indirectly detect low levels of hydroperoxides, at least in fine fragrances. Ideally, one would prefer to directly detect the parent hydroperoxide. Therefore the same samples were further tested with three LC‐based methods directly detecting the parent hydroperoxide. LC coupled to chemiluminescence, LC‐Q‐TOF‐MS or LC‐orbitrap‐MS were used. Results indicate that with specific gradients a separation of the four analytes and quantification in the fragrance matrix can be achieved. Results of this method evaluation study present a toolbox of methods to detect terpene hydroperoxides to further investigate consumer exposure.
Two high‐resolution mass spectrometers (HRMS) with different analyzer technology, Orbitrap and hybrid quadrupole time‐of‐flight (QTOF), were compared with a low‐resolution mass spectrometer, quadrupole, to analyse a set of 35 difficult allergens. These difficult allergens are commonly coeluted fragrance allergens with matrix compounds, using standard gas chromatography‐mass spectrometer conditions, from the extended list of the Scientific Committee on Consumer Safety (SCCS). Although the fundamental role of chromatographic separation has been demonstrated many times, the aim of this work is to demonstrate the benefits of high‐resolution. The added value of high‐resolution was illustrated in both a qualitative and a quantitative way. For qualitative aspect, the high resolution extracted ion signals of these two detectors were compared with the low‐resolution extracted ion signals. About 50% of the coeluted cases observed with the low‐resolution detector are easily resolved by the two high‐resolution detectors. For the quantitative aspect, an accuracy profile methodology and a performance metric were used to propose an overall evaluation. The Orbitrap mass spectrometer demonstrated a better overall performance, while the QTOF presented similar or even lower quantification performances than the quadrupole on the set of analysed fragrances.
Mixed chlorobromoanisoles have recently been recognized as new potential odorous compounds in tap water. The odour threshold concentrations (OTCs) of these compounds are close to the sub ng/L (ppt) and associated descriptors are "earthy, musty, rubber". During a "swampy, musty" episode in water of the Norrtälje district (Sweden), 2,4,6-mixed chlorobromoanisoles and their phenolic precursors were identified. These compounds were synthesised in order to quantify them in different types of waters, Samplings were performed during two different seasons. Results show that whatever the season, mixed haloanisoles and their precursors were present. Chlorination, biofilm activity and residence time in the distribution system seem to be critical factors for the appearance of such compounds.
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