From conventional proton-transfer-reaction mass spectrometry (PTR-MS) to universal trace gas analysis

Sulzer, Philipp; Edtbauer, Achim; Hartungen, Eugen; Jürschik, Simone; Jordan, Alfons; Hanel, G.; Feil, S.; Jaksch, Stefan; Märk, Lukas; Märk, T.D.

doi:10.1016/j.ijms.2012.05.003

Cited by 58 publications

(53 citation statements)

References 18 publications

(20 reference statements)

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“…Adjunction of a switchable reagent ion (SRI) source capable of using complementary charge exchange chemical ionization via NO + or O 2 + . (as in SIFT‐MS) or Kr + have broadened the applicability of PTR‐ToF‐MS. It is out of the scope of this manuscript to cite exhaustively all the results obtained using PTR‐ToF‐MS for foodstuff categorization that have appeared in the literature since the launch of commercial instruments.…”

Section: Introductionmentioning

confidence: 99%

Volatile compounds profiling by using proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). The case study of dark chocolates organoleptic differences

et al. 2019

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Direct‐injection mass spectrometry (DIMS) techniques have evolved into powerful methods to analyse volatile organic compounds (VOCs) without the need of chromatographic separation. Combined to chemometrics, they have been used in many domains to solve sample categorization issues based on volatilome determination. In this paper, different DIMS methods that have largely outperformed conventional electronic noses (e‐noses) in classification tasks are briefly reviewed, with an emphasis on food‐related applications. A particular attention is paid to proton transfer reaction mass spectrometry (PTR‐MS), and many results obtained using the powerful PTR‐time of flight‐MS (PTR‐ToF‐MS) instrument are reviewed. Data analysis and feature selection issues are also summarized and discussed. As a case study, a challenging problem of classification of dark chocolates that has been previously assessed by sensory evaluation in four distinct categories is presented. The VOC profiles of a set of 206 chocolate samples classified in the four sensory categories were analysed by PTR‐ToF‐MS. A supervised multivariate data analysis based on partial least squares regression‐discriminant analysis allowed the construction of a classification model that showed excellent prediction capability: 97% of a test set of 62 samples were correctly predicted in the sensory categories. Tentative identification of ions aided characterisation of chocolate classes. Variable selection using dedicated methods pinpointed some volatile compounds important for the discrimination of the chocolates. Among them, the CovSel method was used for the first time on PTR‐MS data resulting in a selection of 10 features that allowed a good prediction to be achieved. Finally, challenges and future needs in the field are discussed.

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Section: Introductionmentioning

confidence: 99%

Volatile compounds profiling by using proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). The case study of dark chocolates organoleptic differences

et al. 2019

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“…One of the drawbacks of PTR-MS is that only those compounds whose PA is larger than that of H 2 O can be detected. Recently, with the introduction of the Bswitchable reagent ionization^, it is possible to switch between H 3 O + ions ionizing via proton-transfer reactions and NO + and O 2 + , or Kr + ions, thereby providing even greater analytical value and extending the range of measurable compounds [62,63].…”

Section: Direct Apci-hrms and Ptr-hrmsmentioning

confidence: 99%

The role of direct high-resolution mass spectrometry in foodomics

et al. 2015

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Foodomics has been defined as a global discipline in which advanced analytical techniques and bioinformatics are combined to address different questions in food science and nutrition. There is a growing number of works on the development and application of non-targeted omics methods in foodomics, which reflects that this emerging discipline is already considered by the scientific community to be a valuable approach to assess food safety, quality, and traceability as well as for the study of the links between food and health. As a result, there is a clear need for more rapid, high-throughput MS approaches for developing and applying non-targeted studies. Nowadays, direct MS analysis is one of the main choices to achieve high throughput, generating a set of information from the largest possible number of samples in a fast and straightforward way. The use of high- and ultrahigh-resolution MS greatly improves the analytical performance and offers a good combination of selectivity and sensitivity. By using a range of methods for direct sample introduction/desorption/ionization, high-throughput and non-target analysis of a variety of samples can be obtained in a few seconds by HRMS analysis. In this review, a general overview is presented of the main characteristics of direct HRMS-based approaches and their principal applications in foodomics.

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“…quently investigated: (1) instead of H 3 O + different reagent ions (Sulzer et al, 2012) have been used such as NO + , O + 2 , NH + 4 and Kr + , (2) gas chromatographic preseparation of VOCs prior to PTR-QMS detection (Karl et al, 2001;Warneke et al, 2003) and (3) isomers are distinguished by fragmentation patterns generated with collision-induced dissociation (CID) (Müller et al, 2009;Warneke et al, 2004). In addition, other mass spectrometers have been used in place of the quadrupole such as ion traps (Mielke et al, 2008;Prazeller et al, 2003;Warneke et al, 2005a, b) and time of flight (TOF) mass spectrometers (Blake et al, 2004;Tanimoto et al, 2007).…”

Section: Warneke Et Al: Ptr-qms Vs Ptr-tof Comparisonmentioning

confidence: 99%

PTR-QMS versus PTR-TOF comparison in a region with oil and natural gas extraction industry in the Uintah Basin in 2013

et al. 2015

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Abstract.Here we compare volatile organic compound (VOC) measurements using a standard proton-transferreaction quadrupole mass spectrometer (PTR-QMS) with a new proton-transfer-reaction time of flight mass spectrometer (PTR-TOF) during the Uintah Basin Winter Ozone Study 2013 (UBWOS2013) field experiment in an oil and gas field in the Uintah Basin, Utah. The PTR-QMS uses a quadrupole, which is a mass filter that lets one mass to charge ratio pass at a time, whereas the PTR-TOF uses a time of flight mass spectrometer, which takes full mass spectra with typical 0.1 s-1 min integrated acquisition times. The sensitivity of the PTR-QMS in units of counts per ppbv (parts per billion by volume) is about a factor of 10-35 times larger than the PTR-TOF, when only one VOC is measured. The sensitivity of the PTR-TOF is mass dependent because of the mass discrimination caused by the sampling duty cycle in the orthogonal-acceleration region of the TOF. For example, the PTR-QMS on mass 33 (methanol) is 35 times more sensitive than the PTR-TOF and for masses above 120 amu less than 10 times more. If more than 10-35 compounds are measured with PTR-QMS, the sampling time per ion decreases and the PTR-TOF has higher signals per unit measuring time for most masses. For UBWOS2013 the PTR-QMS measured 34 masses in 37 s and on that timescale the PTR-TOF is more sensitive for all masses. The high mass resolution of the TOF allows for the measurements of compounds that cannot be separately detected with the PTR-QMS, such as oxidation products from alkanes and cycloalkanes emitted by oil and gas extraction. PTR-TOF masses do not have to be preselected, allowing for identification of unanticipated compounds. The measured mixing ratios of the two instruments agreed very well (R 2 ≥ 0.92 and within 20 %) for all compounds and masses monitored with the PTR-QMS.

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From conventional proton-transfer-reaction mass spectrometry (PTR-MS) to universal trace gas analysis

Cited by 58 publications

References 18 publications

Volatile compounds profiling by using proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). The case study of dark chocolates organoleptic differences

Volatile compounds profiling by using proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). The case study of dark chocolates organoleptic differences

The role of direct high-resolution mass spectrometry in foodomics

PTR-QMS versus PTR-TOF comparison in a region with oil and natural gas extraction industry in the Uintah Basin in 2013

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