Quantification of hydroperoxides by gas chromatography‐flame ionization detection and predicted response factors

Abstract

The quantification of hydroperoxides is crucial in several areas, in particular in the fragrance domain, because they have been identified as skin sensitizers. The reference compounds necessary to calibrate the instruments have very limited availability, and require drastic storage conditions (-78°C) due to their instability. To overcome these limitations, we propose a GC-FID approach involving their silylation, and the prediction of response factors. This procedure provides a good alternative to a full calibration down to a concentration level of 500 mg/kg, with an underestimation of about 20%. In the analysis of essential oils and fragrance concentrates, larger deviations are found; however, they are not inherent in the technique but rather in the chemistry of hydroperoxides that readily react with aldehydes to form peroxyhemiacetals, thereby decreasing the concentration of free hydroperoxides. These observations are in agreement with quantitative 1 H NMR and HPLC-Chemiluminescence analyses.

Rapid Spectrophotometric Method for Assessing Hydroperoxide Formation from Terpenes in Essential Oils upon Oxidative Conditions

“…The linearity of the system was determined by a six-point 26 It should be mentioned that higher LODs have been described for hydroperoxide assessment by GC and also that prior derivatization is required to yield the corresponding trimethylsilyl derivatives. 15,29 The spectrophotometric results of the present investigation yielded similarly low LODs for photo-oxidized linalool (<5 ppm), linalyl acetate (<5 ppm), and limonene-2-hydroperoxide (<5 ppm) as earlier reported by LC/MS analysis. 30 The recovery of the photometric analysis was determined by spiking experiments.…”

Interlaboratory evaluation of methods to quantify skin sensitizing hydroperoxides potentially formed from linalool and limonene in perfumes

“…Methods using LC–MS/MS or derivatization with a trimethyl silyl reagent followed by GC–MS were reported . These methods were applied to essential oils, but not to consumer products.…”

Quantification of Hydroperoxides by Gas Chromatography with Flame Ionisation Detection

“…9 HPs with higher molecular masses are partially decomposed at high oven elution temperatures and therefore often derivatised to more thermostable species. Most methods involve silylation 11,12 or reduction of HPs to alcohols with sodium sulfite, 9,13 sodium borohydride, 14 triphenylphosphine 9,14 or trimethyl phosphine. 15 Derivatisation to alcohols can be used if the resulting alcohols were not previously present in the sample.…”

“…Additionally, HPs have limited stability, so reliable quantitative methods are needed to assess purity, such as GC-FID with predicted relative response factors or NMR. 11 Quantitative NMR spectrometry is a universal, non-destructive, absolute detection technique and provides a quantitative reference for other analytical methods. Analytes in the μM concentration range can be detected, with precision and accuracy of around 1%.…”