A novel ionization/sampling method termed triboionization was developed. Triboionization is an ionization method that only uses cohesive substances, such as food wrap or sticky tape, and does not require an electrode, electric power supply, heat source, light source, radiation, or gas, unlike most other conventional ambient ionization methods. In this study, the sample compound attached to adhesive tape or plastic wrap was quickly peeled off at a distance of approximately 2 cm from the atmospheric interface of a mass spectrometer. All of the five types of food wrap and 13 types of adhesive tape tested successfully ionized caffeine. Nine out of ten model compounds were detected as the corresponding molecular ions in the positive or negative mode by this ionizing contrivance using an oriented polypropylene adhesive tape. The detected molecular ions were typically protonated molecules or sodium adducts in the positive mode or deprotonated molecules in the negative mode. The elemental compositions of the observed ions were confirmed within 5 ppm by high-resolution mass spectrometry. The triboionization phenomenon was considered to depend on physical and electronic events caused by peeling off a cohesive substance. Triboionization is able to provide a compact ion source using only mechanical mechanisms. Additionally, triboionization allows sticky tape to be used as a convenient sampling device for surface analysis.
The history of the development of the mass spectrometer is also the history of the development of ion sources [1, 2]. In the 1950s–1980s, ionization was executed in a vacuum; electron ionization (EI)  and chemical ionization (CI) , which involve thermal evaporation and thus restrict the available upper molecular weight range, were used. In the 1980s, Barber developed fast atom bombardment (FAB) [5, 6], which does not involve a thermal evaporation process, expanding the mass range and applicability of ionization. In the 1990s, electrospray ionization (ESI) [7, 8] was developed by Fenn and Yamashita, which enabled ionization at atmospheric pressure. Since then, a number of ion sources for mass spectrometry that enable ionization under atmospheric pressure, which are called ambient ionization methods, have been developed , for example, desorption electrospray ionization , atmospheric solid analysis probe , desorption atmospheric pressure photo-ionization (DAPPI) , and direct analysis in real time (DART) [13, 14]. These ambient ionization methods increased the usability of mass spectrometry. Ambient ionization methods are widely used in food inspection [15,16,17], such as food additive analysis and agricultural residue testing, and in forensic chemistry [18, 19] for explosives analysis and illegal drug testing. However, these ambient ionization methods still require heat sources for evaporation, electrodes for discharge, electric power supplies, light sources for excitation, and gases . Inevitably, these ion sources are elaborate and sizable. On the other hand, an ionization method without voltage called solvent-assisted inlet ionization (SAII) has been developed by Trimpin’s group [20, 21]. SAII is an ionization method from only the solution state, like ESI. Also, matrix-assisted ionization (MAI) succeeded to ionize various compounds including biomolecules without peripheral devices. MAI depends on the sublimation of compounds through chemical processes [22, 23].
In this work, we develop a novel mechanical mechanism driven ionization method that does not require a heat source, electric power supply, light source, radiation, or gas. This method was developed as part of our contracted measurement service of mass spectrometry as an analytical center . We often need to measure the mass spectra of compounds not suitable for ESI . Helium used in DART became difficult to obtain because of international situations. Therefore, it was necessary to develop a practical, easy, and cost-effective ion source to complement ESI. Many luminescence phenomena caused by mechanical process were known . Most of these luminescence phenomena were observed as results of discharge events. We considered these mechanical discharge events have potential to ionize organic compounds. However, a mechanical ionization method for mass spectrometer ion source does not exist, up to today. We decided to apply a discharge phenomenon readily available in our laboratory for ionization of organic compounds.
Materials and Methods
We used an Exactive Plus (Thermo Fisher Scientific, Fair Lawn, NJ) mass spectrometer equipped with a Vapur (IonSense, Saugus, MA) atmospheric-pressure mass spectrometer interface. The mass spectrometer had previously been calibrated using a default ESI device . The temperature of the heated capillary was controlled at 250 °C during the measurement. The resolution was set at 35,000 (full width at half maximum) at m/z 200, with an estimated scan rate of 7.2 scans/s.
The elemental compositions of the observed ions were confirmed by high-resolution mass spectrometry  (HRMS). The HRMS measurement errors were < 5 ppm compared with the calculated exact mass.
Caffeine was supplied by Kanto Chemical Co., Inc. (Tokyo, Japan). Reagent-grade sucrose, l-ascorbic acid, and 3-aminoquinoline were obtained from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). We purchased l-(−)-menthol and quinidine from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Hexamethylbenzene (HMB) was obtained from Acros Organics (NJ, USA). Reagent-grade santonin and sodium dodecyl sulfate (SDS) were purchased from Sigma-Aldrich Co., LLC (St. Louis, USA). Elemental analysis-grade acetanilide was obtained from Kishida Chemical Co., Ltd. (Osaka, Japan).
Cohesive Substances, Sampling, and Ionization
We used different types of commercially available food wrap (plastic wrap) and adhesive tape as cohesive substances. A 20-cm-long strip of sticky tape or plastic wrap was cut from the commercial roll. Sampling was performed as follows. In the case of sticky tape, the ground sample (1 mg) was scattered on a glass slide and then stuck to the adhesive side of the sticky tape. In the case of food wrap, ground sample (1 mg) was scattered over an area of approximately 3 cm2 on a piece of food wrap. The strip of sticky tape or food wrap was folded over on the adhesive side so that ground sample was inside the folded strip. The folded strip was quickly peeled apart at a distance of 2 cm from the Vapur inlet of the mass spectrometer (Figure 1, S_movie. 1).
Results and Discussion
Cohesive Substance and Observed Ions
Initially, we compared the ionization abilities of 13 types of adhesive tape (Table 1, S_Figure 1) and five types of food wrap (Table 2, S_Figure 2). Caffeine was used as the sample compound. All of the cohesive substances were able to ionize caffeine. In most cases, the protonated molecule ([M + H]+), sodium adduct ion ([M + Na]+), deprotonated dimer cation ([2M − H]+), and dimer sodium adduct ([2M + Na]+) were detected as related molecular ions (Figure 2). Sodium adducts are commonly observed in ESI . In particular, [M + H]+ and [M + Na]+ were detected simultaneously in ESI mass spectra of caffeine . The elemental compositions of the observed ions were confirmed within 5 ppm by HRMS. Furthermore, ions with m/z 59, 209, and 253 were observed frequently, which were considered to be fragment ions of caffeine or the caffeine dimer because these three peaks were detected using substances both with and without adhesives. In this experiment, we only investigated the ionization ability of simple inward folding of the strip (i.e., adhesive side–adhesive side). However, we also observed ions originating from the sample after fast peeling of strips with adhesive side–base tape side folding; the sample folded against a smooth surface, such as polyethylene sheet, and, only in the case of plastic wrap, inside out folding (data not shown).
To facilitate sample handling and ionization, 1 mg of sample compound was used in each experiment. Ionization efficiency difference was observed in the cohesive substance used. In general, the rubber-based adhesive tapes performed more stable ionization than the acryl-based adhesive tapes. In this study, the Vapur: aspirating mass spectrometer interface was required in our experimental conditions. We tried to perform ionization in front of bare heated capillary of Exactive Plus; however, ions were not observed. Vapur might be an important force to transport produced ions from the peeled surfaces to inlet of mass spectrometer. The stripped surfaces were assumed to be positively or negatively charged , which might prevent free flight of the produced ions. Sufficient tests to confirm reproducibility were not performed, but some correlations were observed between the peeling velocity and intensity of the detected ions. It was difficult to measure absolute ion intensity because we were unable to fix the relative position of the peeling point and mass interface exactly to refer Figure 1 and S_movie. 1. Roughly estimated relative ion intensities are listed in Tables 1 and 2. To evaluate the ionization efficiency of this method, it is necessary to develop a specific device for these experiments.
Subsequently, we examined the sample applicability of this ionization method using oriented polypropylene (OPP) tape (No. 40, Kyowa, Osaka, Japan) with acryl-based adhesive. This OPP tape enabled stable ionization and low background and did not scatter sample powder around the mass inlet. Acetanilide (molecular weight (MW) = 135.16 (g/mol)), 3-aminoquinoline (MW = 144.17), l-(−)-menthol (MW = 156.27), HMB (MW = 162.27), l-ascorbic acid (MW = 176.13), caffeine (MW = 194.19), santonin (MW = 246.31), SDS (MW = 288.46), quinidine (MW = 324.42), and sucrose (MW = 342.30) were used as sample compounds. Apart from SDS and sucrose, the other eight compounds were employed as test compounds in our previous work investigating the ion source applicability of DART, ESI, and FAB [25, 28]. In our previous studies, l-(−)-menthol was not detected (ND) after FAB, and HMB was ND after ESI in the positive mode. In this study, both the positive and negative modes were examined; the results are summarized in Table 3 (S_Figure 3). In the positive mode, almost all of the model compounds were detected as [M + H]+ or [M + Na]+, only HMB was ND. However, polyester fiber base gaffer tape with rubber-based adhesive (No. 600, Sekisui Chemical Co., Ltd., Osaka, Japan) successfully ionized HMB, which was detected as [M + H]+ (S_Figure 4). These results suggest the possibility of optimizing the adhesive and tape base to improve ionization efficiency. Sample compounds were sometimes detected as dimer-related ions. Both the protonated dimer ([2M + H]+) and [2M + Na]+ were detected for acetanilide and l-ascorbic acid (Figure 3). The potassium adduct ([M + K]+) and dimer potassium adduct ([2M + K]+) were only detected for santonin (Figure 4). It was considered that santonin had high potassium affinity because [M + K]+ was observed in its ESI mass spectrum. In the negative mode, 3-aminoquinoline, l-(−)-menthol, HMB, and quinidine were ND. However, the deprotonated molecule ([M − H]−) was detected for acetanilide, l-ascorbic acid (Figure 3), caffeine (HRMS did not match for calibration problem), santonin, and sucrose in the negative mode. The deprotonated dimer ([2M − H]−) was also observed for acetanilide and l-ascorbic acid (Figure 3). In the case of SDS, the dodecyl sulfate ion ([M − Na]−) was detected in the negative mode (S_Figure 3). These results showed that proton and sodium exchanges occurred with charge transfer between the sample compounds and/or adhesive as a matrix.
Proposed Ionization Mechanism
Various charge-related events are known to occur upon peeling a cohesive substance [30, 31]. For example, triboluminescence [32,33,34] is a luminous phenomenon observed when peeling off adhesive tape. Micro-discharge events occur that radiate electromagnetic waves, which can include X-ray radiation in case of in a vacuum . These micro-discharge events occurred in the near field of the sample compounds and were considered to involve the following chemical reactions: (1) Radiated electrons ionized the sample compound directly, like for EI. (2) Emitted protons formed adducts with the sample compound. (3) Charge transfer affected on the components substance of adhesive like matrix and then a proton or sodium ion forms an adduct with the sample molecule. (4) Emitted proton or electron excites components of atmospheric air, such as water vapor; then, these excited chemical species ionized the sample compound, like in CI. (5) Light produced by triboluminescence ionized sample compounds, like in DAPPI  (Figure 5). Mechanical energy or heat generation might affect the ionization of the sample compound [37,38,39] because the peeling off of adhesive tape generates heat. There is also the possibility of topically high-temperature assisted evaporation; however, it is unlikely that ionization was caused by heating only. Reaction 1 may occur. However, this reaction was assumed not to be prominent because molecular ions ([M]+•) were not observed as major components, as is the case in conventional EI. Reaction 2 refers to one of the pathways, in which the proton sources were considered to adsorb water on the cohered substance surface. Reaction 3 might be a major pathway because [M + Na]+ was observed in many cases. Reaction 4 is considered to be a major ionization mechanism of DART and is undeniable in this ionization method. Reaction 5 was considered not to be a major pathway because it was difficult to supply enough energy for ionization. In addition, adduct ions were observed in most cases. The electron or charge transfer events occur when peeling off cohesive substances are not yet understood completely [40, 41]. Consequently, we were unable to confirm the mechanism of this ionization by peeling off cohesive substances. However, we considered that multiple factors were involved in this ionization method. Furthermore, adhesives were not requisite in this ionization; ionization was also observed when using plastic wrap, which lacks adhesive. The essence of this ionization was the effects of peeling off a substance adhered by van der Waals and/or Coulomb forces. We collectively term this ionization technique involving peeling off a cohesive substance as triboionization. Further elucidation of the triboionization process is planned for the future, especially regarding the ionization mechanism.
The similarities of Trimpin’s SAII and MAI, and our triboionization, were considered. In particular, these three ionization methods are similar because they induce ionization without any heat source for evaporation, electrode for discharge, electric power supply, light source for excitation, or gas. Basically, SAII and MAI depend on the chemical processes of a matrix or solution [20,21,22,23]. SAII is different from triboionization because it involves ionization from the solution state [20, 21]. Meanwhile, MAI requires a matrix. Additionally, MAI processes including sublimation and ionization occur while small particles move from atmospheric pressure to vacuum . In addition, Trimpin considers triboluminescence to be involved in the mechanism of MAI . In contrast, triboionization does not require an ionization-supporting liquid or matrix; it occurs readily simply by peeling off a pure plastic film. It is considered that the mechanical motion of the peel-off process induces discharge or charge transfer at the surface-attached substance [41, 42], as previously discussed. At least, ions of atmospheric molecules were generated during the peeling off process of cohesive substance [41, 42]; that is, compounds in the vicinity of the cohesive substance during peeling were ionized by discharge or charge transfer events. As an example, a background mass spectrum was collected by conducting triboionization using only sticky tape without an analyte compound added (S_Figure 5). In triboionization, ions were generated in the atmospheric conditions, which is a definite difference from the behavior in MAI and SAII. In addition, triboionization was able to generate negative ions easily, form alkali metal adducts up to potassium adducts (Figure 4), and ionize non-polar molecules such as HMB (S_Figure 4). Moreover, triboionization involves a mechanical process, unlike other conventional ionization methods. Therefore, we believe that triboionization is distinct from conventional ionization methods.
Triboionization is a novel practical ionization method that is able to ionize various compounds without any electrodes, electric power, heating, light, radiation, or gas. These features make triboionization suitable to provide a novel compact ion source for on-site mass spectrometry . The ability to perform sampling using the same sticky tape for ionization is one feature of triboionization. Such sticky tape based sampling involves information about sampling place that spatial resolution depends on tape width or sampling interval. Triboionization also allows effective sample preservation (Figure 6). These features make triboionization suitable for forensic analysis of compounds such as explosives and drugs in powder form. Likewise, if the sensitivity of the method can be improved sufficiently, residual pesticide analysis of edible leaves and fruit is potentially an application of triboionization because it would allow easy sampling at remote locations without sample preparation. The analysis of secretions or/and accretions of exposed biological samples, i.e., skin, nails, and hair, could be possible using triboionization. The sticky tape works as an ionization device and also as a sampling device to enable efficient and practical mass spectrometry.
To achieve stable ionization, the peeling mechanism of the adhesive tape needs to be improved. Ideally, a device that maintains the peeling point a certain distance from the mass spectrometer inlet and provides a controllable peeling velocity is desirable. Additionally, the cohesive substance used in triboionization is not restricted to a film or sheet. For example, continuous and stable ionization is expected from a rotating roller located in front of a mass spectrometer inlet when a roller with attached sample compound is pressed to the rotating roller. Such a setup could allow continuous attachment and detachment of the surfaces of the two rollers.
There are still possibilities to improve the adhesives used for triboionization. The rubber-based adhesives yielded greater signals for the analytes than acryl-based adhesives in this work. Moreover, backgrounds were observed from some adhesive tapes. All the types of food wrap and most types of sticky tape tested had no obvious backgrounds peaks without analyte compounds present. However, background ions were observed from No. 600 adhesive tape (Sekisui Chemical Co., Ltd., Osaka, Japan) (S_Figure 5). It is considered that adhesives other than rubber and acryl base adhesives are possible, for example, adhesives that allow repeatable use would be convenient. Additionally, dopants could be added to the adhesive to ensure stable ionization or induce adduct formation. Regarding the tape base, gaffer, OPP, cellophane, and polyimide tapes were all able to ionize caffeine; however, it may be possible to control the ionization efficiency by regulating the conductivity of the base tape.
A novel ionization method termed triboionization was developed that involves a simple mechanical peeling process of cohesive substances without voltage, heat, light, radiation, or gas required. We obtained mass spectra of sample compounds adhered to cohesive substances (food wrap and adhesive tape) after peeling; typically, [M + H]+ and [M + Na]+ were observed in the positive mode, and [M − H]− was observed in the negative mode. The mechanism of triboionization still needs further investigation, and the development of various applications is anticipated.
Brunnee, C.: 50 years of MAT in Bremen. Rapid Commum. Mass Spectrom. 11, 694–707 (1997)
Doerr, A., Finkelstein, J., Jarchum, I., Goodman, C., Dekker, B.: Nature Milestones Mass Spectrometry. Springer Nature, New York (2015) https://www.nature.com/milestones/mass-spec Accessed December 20, 2018
Tate, J.T., Smith, P.T.: Ionization potentials and probabilities for the formation of multiply charged ions in the alkali vapors and in krypton and xenon. Phys. Rev. 46(9), 0773–0776 (1934)
Munson, M.S.B., Field, F.H.: Chemical ionization mass spectrometry. I. general introduction. J. Am. Chem. Soc. 88(12), 2621–2630 (1966)
Barber, M., Bordoli, R.S., Sedgwick, R.D., Tyler, A.N.: Fast atom bombardment of solids as an ion-source in mass-spectrometry. Nature. 293(5830), 270–275 (1981)
Barber, M., Bordoli, R.S., Elliott, G.J., Sedgwick, R.D., Tyler, A.N.: Fast atom bombardment mass-spectrometry. Anal. Chem. 54(4), A645–A657 (1982)
Fenn, J.B., Mann, M., Meng, C.K., Wong, S.F., Whitehouse, C.M.: Electrospray ionization for mass-spectrometry of large biomolecules. Science. 246(4926), 64–71 (1989)
Yamashita, M., Fenn, J.B.: Electrospray ion-source - another variation on the free-jet theme. J. Phys. Chem. 88(20), 4451–4459 (1984)
Monge, M.E., Harris, G.A., Dwivedi, P., Fernández, F.M.: Mass spectrometry: recent advances in direct open air surface sampling/ionization. Chem. Rev. 113, 2269–2308 (2013)
Takáts, Z., Wiseman, J.M., Gologan, B., Cooks, R.G.: Mass spectrometry sampling under ambient conditions with desorption electrospray ionization. Science. 306(5695), 471–473 (2004)
McEwen, C.N., McKay, R.G., Larsen, B.S.: Analysis of solids, liquids, and biological tissues using solids probe introduction at atmospheric pressure on commercial LC/MS instruments. Anal. Chem. 77(23), 7826–7831 (2005)
Haapala, M., Pól, J., Saarela, V., Arvola, V., Kotiaho, T., Ketola, A.R., Franssila, S., Kauppila, J.T., Kostiainen, R.: Desorption atmospheric pressure photoionization. Anal. Chem. 79(20), 7867–7872 (2007)
Cody, R.B., Laramée, J.A., Durst, H.D.: Versatile new ion source for the analysis of materials in open air under ambient conditions. Anal. Chem. 77(8), 2297–2302 (2005)
Gross, J.H.: Direct analysis in real time—a critical review on DART-MS. Anal. Bioanal. Chem. 406(1), 63–80 (2014)
Pavlovich, M.J., Dunn, E.E., Hall, A.B.: Chemometric brand differentiation of commercial spices using direct analysis in real time mass spectrometry. Rapid Commun. Mass Spectrom. 30(9), 1123–1130 (2016)
Rajchl, A., Prchalová, J., Kružík, V., Ševčík, R., Čížková, H.: Evaluation of ice-tea quality by DART-TOF/MS. J. Mass Spectrom. 50(11), 1214–1221 (2015)
Ackerman, L.K., Noonan, G.O., Begley, T.H.: Assessing direct analysis in real-time-mass spectrometry (DART-MS) for the rapid identification of additives in food packaging. Food Addit. Contam. Part A Chem. Anal. Control Expo. Risk Assess. 26(12), 1611–1618 (2009)
Bridoux, M.C., Schwarzenberg, A., Schramm, S., Cole, R.B.: Combined use of direct analysis in real-time/Orbitrap mass spectrometry and micro-Raman spectroscopy for the comprehensive characterization of real explosive samples. Anal. Bioanal. Chem. 408(21), 5677–5687 (2016)
Lesiak, A.D., Musah, R.A.: Application of ambient ionization high resolution mass spectrometry to determination of the botanical provenance of the constituents of psychoactive drug mixtures. Forensic Sci. Int. 266, 271–280 (2016)
Pagnotti, V.S., Chubatyi, N.D., McEwen, C.N.: Solvent assisted inlet ionization: an ultrasensitive new liquid introduction ionization method for mass spectrometry. Anal. Chem. 83, 3891–3895 (2011)
Pagnotti, V.S., Inutan, E.D., Marshall, D.D., McEwen, C.N.: Inlet ionization: a new highly sensitive approach for liquid chromatography/mass spectrometry of small and large molecules. Anal. Chem. 83, 7591–7594 (2011)
Trimpin, S., Lu, I.-C., Rauschenbach, S., Hoang, K., Wang, B., Chubaty, N.D., Zhang, W.-J., Inutan, E.D., Pophristic, M., Sidorenko, A., McEwen, C.N.: Spontaneous charge separation and sublimation process are ubiquitous in nature and in ionization process in mass spectrometry. J. Am. Soc. Mass Spectrom. 29, 304–315 (2018)
Trimpin, S.: “Magic” ionization mass spectrometry. J. Am. Soc. Mass Spectrom. 27, 4–21 (2016)
Izutani, C., Fukagawa, D., Miyashita, M., Ito, M., Sugimura, N., Aoyama, R., Gotoh, T., Shibue, T., Igarashi, Y., Oshio, H.: The materials characterization central laboratory: an open-ended laboratory program for fourth-year undergraduate and graduate students. J. Chem. Educ. 93(9), 1667–1670 (2016)
Sugimura, N., Furuya, A., Yatsu, T., Shibue, T.: Comparison of the applicability of mass spectrometer ion sources using a polarity–molecular weight scattergram with a 600 sample in-house chemical library. Eur. J. Mass Spectrom. 21, 91–96 (2015)
Jha, P., Chandra, B.P.: Survey of the literature on mechanoluminescence from 1605 to 2013. Luminescence. 29, 977–993 (2014)
Aiken, A.C., DeCarlo, P.F., Jimenez, J.L.: Elemental analysis of organic species with electron ionization high-resolution mass spectrometry. Anal. Chem. 79(21), 8350–8358 (2007)
Sugimura, N., Furuya, A., Yatsu, T., Shibue, T.: Prediction of adducts on positive mode electrospray ionization mass spectrometry: proton/sodium selectivity in methanol solutions. Eur. J. Mass Spectrom. 21, 725–731 (2015)
Baytekin, T.H., Patashinski, Z.A., Branicki, M., Baytekin, B., Soh, S., Grzybowski, A.B.: The mosaic of surface charge in contact electricfixation. Science. 333, 308–312 (2011)
Deryagin, B.V.: Adhesion of solids. Consultants Bureau, New York (1978)
Harper, W.R.: Contact and frictional electrification. Laplacian Press, Morgan Hill (1998)
Walton, A.J.: Triboluminescence. Adv. Phys. 26(6), 887–948 (1977)
Harvey, N.E.: The luminescence of adhesive tape. Science. 89(2316), 460–461 (1939)
Zhenyi, M., Fan, J., Dickinson, J.T.: Properties of the photon emission accompanying the peeling of a pressure-sensitive adhesive. J. Adhesion. 25(1), 63–77 (1988)
Camara, G.C., Escobar, V.J., Hird, R.J., Putterman, J.S.: Correlation between nanosecond X-ray flashes and stick–slip friction in peeling tape. Nature. 455(23), 1089–1093 (2008)
Alcock, G.W., Hayward, J.E., Mile, B., Ward, B.: Chemical reactions of methane in a triboelectric discharge. Can. J. Chem. 50, 3813–3820 (1972)
Kendall, K.: Thin-film peeling—the elastic term. J. Phys. D. 8, 1449–1452 (1975)
Chikina, I., Gay, C.: Cavitation in adhesives. Phys. Rev. Lett. 85(21), 4546–4549 (2000)
Urahama, Y.: Effect of peel load on stringiness phenomena and peel speed of pressure-sensitive adhesive tape. J. Adhesion. 31(1), 47–58 (1989)
Black, R.A., Hallett, J.: The mystery of cloud electrification. Am. Sci. 86, 526–534 (1998)
McCarty, L., Whitesides, G.M.: Electrostatic charging due to separation of ions at interfaces: contact electrification of ionic electrets. Angew. Chem. Int. Ed. 47, 2188–2207 (2008)
Alexander, A.J.: Interfacial ion-transfer mechanism for the intense luminescence observed when opening self-seal envelops. Langmuir. 28, 13294–13299 (2012)
Mächler, L., Brennwald, S.M., Tyroller, L., Livingstone, M.D., Kipfer, R.: Conquering the outdoors with on-site mass spectrometry. Chimia. 68, 155–159 (2014)
The authors deeply grateful to Professor Joseph A. Loo of University of California Los Angeles for useful comments and editorial suggestions.
Electronic Supplementary Material
About this article
Cite this article
Sugimura, N., Watabe, Y. & Shibue, T. Triboionization: a Novel Ionization Method by Peeling of Cohesive Substances for Mass Spectrometry. J. Am. Soc. Mass Spectrom. 30, 1503–1511 (2019). https://doi.org/10.1007/s13361-019-02220-8
- Sticky tape
- Food wrap
- Adhesive tape
- Van der Waals force
- Coulomb force
- Surface analysis