Comparison of direct mass spectrometry methods for the on‐line analysis of volatile compounds in foods

Abstract

For the on-line monitoring of flavour compound release, atmospheric pressure chemical ionization (APCI) and proton transfer reaction (PTR) combined to mass spectrometry (MS) are the most often used ionization technologies. APCI-MS was questioned for the quantification of volatiles in complex mixtures, but direct comparisons of APCI and PTR techniques applied on the same samples remain scarce. The aim of this work was to compare the potentialities of both techniques for the study of in vitro and in vivo flavour release. Aroma release from flavoured aqueous solutions (in vitro measurements in Teflon bags and glass vials) or flavoured candies (in vivo measurements on six panellists) was studied using APCI- and PTR-MS. Very similar results were obtained with both techniques. Their sensitivities, expressed as limit of detection of 2,5-dimethylpyrazine, were found equivalent at 12 ng/l air. Analyses of Teflon bag headspace revealed a poor repeatability and important ionization competitions with both APCI- and PTR-MS, particularly between an ester and a secondary alcohol. These phenomena were attributed to dependency on moisture content, gas/liquid volume ratio, proton affinities and product ion distribution, together with inherent drawbacks of Teflon bags (adsorption, condensation of water and polar molecules). Concerning the analyses of vial headspace and in vivo analyses, similar results were obtained with both techniques, revealing no competition phenomena. This study highlighted the equivalent performances of APCI-MS and PTR-MS for in vitro and in vivo flavour release investigations and provided useful data on the problematic use of sample bags for headspace analyses.

The role of direct high-resolution mass spectrometry in foodomics

“…In a recent study, APCI-MS and PTR-MS provided equivalent results for the study of in vitro and in vivo flavor release [61]. Although a higher degree of fragmentation was observed with PTR-MS, similar response linearity and sensitivities were obtained.…”

Real-Time Monitoring of Exhaled Volatiles Using Atmospheric Pressure Chemical Ionization on A Compact Mass Spectrometer

“…In addition to the acetone monomer, a water cluster of acetone [acetone+H 2 O+H] + and proton-bound dimer …”

“…Areas of interest include point-of-care medical diagnostics, for example determining narcotic and alcohol intoxication [1], and food chemistry, as a method of monitoring aroma compounds and flavor release [2]. There are a number of different technologies available for these applications including ion mobility spectrometry [3], chemical sensors (e.g.…”

Feasibility and application of a retronasal aroma‐trapping device to study in vivo aroma release during the consumption of model wine‐derived beverages

“…2000) or the off-line monitoring by trapping the exhaled breath after swallowing (by the nose or mouth) onto adsorbent polymers (Delahunty et al 1996; Buettner and Schieberle 2000; Lasekan et al 2009). The online monitoring of aroma release by API-MS and PTR-MS has been proven as a sensitive and very valuable tool allowing the real-time monitoring of aroma compounds during eating, permitting the collection of valuable data to compare with the sensory analysis of the same product (Munoz-Gonzalez et al 2011; Deleris et al 2013). However, some constraints of this approach are the difficulties in the identification of aroma compounds with the same nominal mass (isobaric compounds), the assignment of fragments of the compound of interest produced during the ionization process, or the identification of aroma compounds when analyzing real food samples with complex aroma mixtures (Munoz-Gonzalez et al 2011; Poinot et al 2013).…”