Low Temperature Plasma Ionization Research Articles

Rapid detection of furanyl fentanyl in complex matrices using Leidenfrost desorption-assisted low-temperature arc plasma ionization mass spectrometry.

The abuse of illicit drugs poses serious threats to the physical and mental health of users, as well as to the overall safety and welfare of society. In this work, we present a newly developed technique for drug detection based on mass spectrometry. This technique combines Leidenfrost desorption with low-temperature arc plasma ionization mass spectrometry. This method is applicable for detecting furanyl fentanyl in complex matrices. Key advantages of this technique include minimal sample fragmentation and high sensitivity for detection. The Leidenfrost desorption plays a pivotal role in this methodology, as it spontaneously concentrates analyte molecules during the gradual evaporation of the solvent. Eventually, these concentrated molecules are redistributed at their highest concentrations, resulting in exceptionally high sensitivity. In the course of our investigation, we achieved a remarkable detection limit of 10 pg mL-1 for furanyl fentanyl in pure water. Moreover, the characteristic ion peaks of furanyl fentanyl can be distinctly identified within complex matrices such as wine, beverages, urine, and lake water. This innovative drug detection technology offers several advantages, including a simple setup, cost-effectiveness, rapid detection, high sensitivity, and minimal sample pretreatment.

Measurement of Atmospheric Volatile and Intermediate Volatility Organic Compounds: Development of a New Time-of-Flight Mass Spectrometer

A new gas inlet port combined with a novel ionization scheme have been developed and coupled to a high-resolution time-of-flight mass spectrometer (TOF MS) for the detection and measurement of atmospheric volatile (VOCs) and intermediate volatility organic compounds (IVOCs). Ions are produced predominantly by charge transfer reactions in a low-temperature plasma ionization source with minimal fragmentation. Enhanced sensitivity is accomplished by incorporating an increased-size inlet capillary in a transverse arrangement to maximize throughput in the ionization source. Additional design aspects of the new mass spectrometer enabling superior transmission include a large acceptance ion funnel and a segmented radio frequency (RF) ion guide with increased space charge storage capacity. An orthogonal TOF analyzer equipped with a two-stage reflectron and tuned to second order is employed for the determination of the mass-to-charge ratio of the ions, with a mass resolving power of >20 k at mass 500 Th. The performance of the instrument was evaluated in tests using VOC standards and in atmospheric chamber experiments to demonstrate the ability to measure a wide range of organic compounds with different functional groups. Linear signal response is demonstrated over a wide range of VOCs used in the calibration processes in the ppb range, while the instrument exhibits linear response in the ppt range as well. Detection limits as low as 1 ppt are accomplished. The potential applications of this new TOF MS instrument were demonstrated in a pilot atmospheric simulation chamber experiment.

In Vivo Low-Temperature Plasma Ionization Mass Spectrometry (LTP-MS) Reveals Regulation of 6-Pentyl-2H-Pyran-2-One (6-PP) as a Physiological Variable during Plant-Fungal Interaction.

Volatile organic compounds (VOCs) comprises a broad class of small molecules (up to ~300 g/mol) produced by biological and non-biological sources. VOCs play a vital role in an organism's metabolism during its growth, defense, and reproduction. The well-known 6-pentyl-α-pyrone (6-PP) molecule is an example of a major volatile biosynthesized by Trichoderma atroviride that modulates the expression of PIN auxin-transport proteins in primary roots of Arabidopsis thaliana during their relationship. Their beneficial relation includes lateral root formation, defense induction, and increased plant biomass production. The role of 6-PP has been widely studied due to its relevance in this cross-kingdom relationship. Conventional VOCs measurements are often destructive; samples require further preparation, and the time resolution is low (around hours). Some techniques enable at-line or real-time analyses but are highly selective to defined compounds. Due to these technical constraints, it is difficult to acquire relevant information about the dynamics of VOCs in biological systems. Low-temperature plasma (LTP) ionization allows the analysis of a wide range of VOCs by mass spectrometry (MS). In addition, LTP-MS requires no sample preparation, is solvent-free, and enables the detection of 6-PP faster than conventional analytical methods. Applying static statistical methods such as Principal Component Analysis (PCA) and Discriminant Factorial Analysis (DFA) leads to a loss of information since the biological systems are dynamic. Thus, we applied a time series analysis to find patterns in the signal changes. Our results indicate that the 6-PP signal is constitutively emitted by T. atroviride only; the signal shows high skewness and kurtosis. In A. thaliana grown alone, no signal corresponding to 6-PP is detected above the white noise level. However, during T. atroviride-A. thaliana interaction, the signal performance showed reduced skewness and kurtosis with high autocorrelation. These results suggest that 6-PP is a physiological variable that promotes homeostasis during the plant-fungal relationship. Although the molecular mechanism of this cross-kingdom control is still unknown, our study indicates that 6-PP has to be regulated by A. thaliana during their interaction.

Analysis of liquid samples by Low-Temperature Plasma Ionization Source-ion mobility spectrometry

In this study, liquid pharmaceutical samples are analyzed using an ion mobility spectrometer (IMS) with the Low-Temperature Plasma Ionization Source (LTPI) for the first time, overcoming limitations for this system due to intense interaction with IMS cell without sample pre-preparation. The direct sample introduction or newer methods that were presented in recent years in the LTP-MS are useful in mass spectroscopy, but these methods are incompetent in IMS. In new LTP-IMS, first, the sample is vaporized, then transferred to the ionization source by the carrier gas, and finally ionized. The new method has several salient characteristics as follows in comparison to the other similar devices. A new efficient way for sample entering which needs less amount of sample, does not waste it and ionizes liquid samples without any preparation or pre-extraction because the ionization source can vaporize, desorb, and ionize the samples simultaneously. In this work, the IMS cell, LTP, and sample introduction system must sync together, so they were redesigned to eliminate incompatibilities. Afterward, to achieve the best response, before evaluating the device, all parameters consist of gas flow, voltage, frequency, exhaust diameter of source, and IMS cell parameters were optimized. Then several pharmaceutical samples, including Papaverine, Codeine, Caffeine, and Diethylamine were analyzed to evaluate the qualitative and quantitative characteristics of the device. The samples were dissolved in methanol and detected in a few seconds, with a low detection limit of 41.75 ng for Codeine, 7.50 ng, and 8.25 ng for Caffeine and Papaverine, respectively.

Analyzing the Distribution of Specialized Metabolites from Plant Native Tissues with Laser Desorption Low-Temperature Plasma Mass Spectrometry Imaging.

The localization of metabolites in plant tissues is often related to their biological function and biosynthesis. Mass spectrometry imaging (MSI) provides comprehensive information about the distribution of known and unknown compounds in tissues. In this protocol, we describe the use of laser desorption low-temperature plasma (LD-LTP) ionization MSI. This technology enables the direct analysis of native tissues under ambient conditions.

Development of an inverse low-temperature plasma ionization source for liquid chromatography/mass spectrometry.

An argon inverse low-temperature plasma (iLTP) ionization source for liquid chromatography/tandem mass spectrometry was developed. The iLTP is constructed from simple chromatographic supply materials and is implemented into an atmospheric pressure chemical ionization (APCI) source replacing the APCI discharge needle electrode. The newly developed ion source was coupled to an ultra-high-performance liquid chromatography (UHPLC) system. The argon iLTP was characterized by optical emission spectroscopy. The soft ionization of selected standards was also demonstrated by direct infusion experiments. In addition to the use of argon as the discharge gas, helium, synthetic air, and oxygen were used, which were tested for their performance using testosterone and vitamin D3 . Spectroscopic measurements of the argon plasma were conducted, demonstrating the main emission band of argon metastables with corresponding energies of 11.53 eV and 11.72 eV. Infusion experiments indicate a gentle ionization by iLTP, e.g. caffeine, testosterone, reserpine, vitamin D3 , and 25-hydroxyvitamin D3 , which resulted in the corresponding protonated molecules. The splitless coupling with UHPLC (possible flow rates >1000 μL min-1 ) shows promising results in interday repeatability (n = 10) for the substances with a relative standard deviation of less than 5% and limits of detection for caffeine, testosterone, reserpine, vitamin D3 , and 25-hydroxyvitamin D3 of 10 ng L-1 , 50 ng L-1 , 500 ng L-1 , 5 μg L-1 , and 5 μg L-1 , respectively. The argon iLTP ion source presented in this work shows promising approaches in the field of ionization of small organic molecules. The mechanism related to the discharge gas argon has not been elucidated so far and further investigations are needed. The iLTP ion source shows a very good performance with UHPLC coupling, even at increased flow rates. It could be shown that an argon iLTP can compete with the helium dielectric barrier discharge (DBD) preferred in the literature, making it a more economical choice.

Surface acoustic wave nebulization improves compound selectivity of low-temperature plasma ionization for mass spectrometry

Mass spectrometry coupled to low-temperature plasma ionization (LTPI) allows for immediate and easy analysis of compounds from the surface of a sample at ambient conditions. The efficiency of this process, however, strongly depends on the successful desorption of the analyte from the surface to the gas phase. Whilst conventional sample heating can improve analyte desorption, heating is not desirable with respect to the stability of thermally labile analytes. In this study using aromatic amines as model compounds, we demonstrate that (1) surface acoustic wave nebulization (SAWN) can significantly improve compound desorption for LTPI without heating the sample. Furthermore, (2) SAWN-assisted LTPI shows a response enhancement up to a factor of 8 for polar compounds such as aminophenols and phenylenediamines suggesting a paradigm shift in the ionization mechanism. Additional assets of the new technique demonstrated here are (3) a reduced analyte selectivity (the interquartile range of the response decreased by a factor of 7)—a significant benefit in non-targeted analysis of complex samples—and (4) the possibility for automated online monitoring using an autosampler. Finally, (5) the small size of the microfluidic SAWN-chip enables the implementation of the method into miniaturized, mobile LTPI probes.

A 3-in-1 Hand-Held Ambient Mass Spectrometry Interface for Identification and 2D Localization of Chemicals on Surfaces.

Desorption electrospray ionization (DESI), easy ambient sonic-spray ionization (EASI) and low-temperature plasma (LTP) ionization are powerful ambient ionization techniques for mass spectrometry. However, every single method has its limitation in terms of polarity and molecular weight of analyte molecules. After the miniaturization of every possible component of the different ion sources, we finally were able to embed two emitters and an ion transfer tubing into a small, hand-held device. The pen-like interface is connected to the mass spectrometer and a separate control unit via a bundle of flexible tubing and cables. The novel device allows the user to ionize an extended range of chemicals by simple switching between DESI, voltage-free EASI, or LTP ionization as well as to freely move the interface over a surface of interest. A mini camera, which is mounted on the tip of the pen, magnifies the desorption area and enables a simple positioning of the pen. The interface was successfully tested using different types of chemicals, pharmaceuticals, and real life samples. Moreover, the combination of optical data from the camera module and chemical data obtained by mass analysis facilitates a novel type of imaging mass spectrometry, which we name “interactive mass spectrometry imaging (IMSI)”.

The ionization process of chemical warfare agent simulants in low temperature plasma ionization.

The application of low-temperature plasma ionization technology in the chemical warfare agent detection was mostly focused on the research of rapid detection methods. Limited studies are available on the ionization process of chemical warfare agents in low temperature plasma. Through the intensity of protonated molecules of dimethyl methylphosphonate (DMMP) in different solvents including methanol, deuterated methanol (methanol-D4), pure water, and deuterium oxide (water-D2), it was concluded that the water molecule in the air provides the hydrogen ion (H+) needed for ionization. The product ion spectra and the collision-induced dissociation processes of protonated molecules of nerve agent simulants, including DMMP, diethyl methanephosphonate (DEMP), trimethyl phosphate (TMP), triethyl phosphate (TEP), tripropyl phosphate (TPP), and tributyl phosphate (TBP) were analyzed. Results revealed that H+ mostly combined with phosphorus oxygen double bond (P = O) in the low-temperature plasma ionization. By analyzing the peak intensity distribution of product ions of protonated molecules, the presence of proton and charge migration in the low temperature plasma ionization and collision-induced dissociation were researched. This study could provide technical guidance for the rapid and accurate detection of chemical warfare agents through low temperature plasma ionization-mass spectrometry.

Open LabBot and RmsiGUI: Community development kit for sampling automation and ambient imaging

Building novel analytical systems requires various elements: Sensors, a sampling system and data evaluation software. For emerging technologies, such as ambient ionization mass spectrometry (AIMS), the assembly of a functional prototype is often more time-consuming than developing the actual probes. The modification of commercial platforms for testing hardware is usually not possible due to technical and legal restrictions. Therefore, we designed a robotic platform, which is based on RepRap 3D-printer components, and therefore easy to adopt for custom set-ups. Adjustable rails in an aluminium frame construction facilitate the mounting of additional parts such as sensors, probes, or optical components. The Open LabBot uses industry-standard G-code for its control. Its simple syntax facilitates the programming of the movement. We developed two programs for the robot control and mass spectrometry imaging: “LABI-Imaging” for synchronizing the robot movements and MS data acquisition and “RmsiGUI”, a software solution for the complete AIMS workflow. We proved the functionality of the system by the automated sampling and classification of essential oils with a PlasmaChip probe. Further, we performed an AIMSI imaging experiment of a lime slice with laser desorption low-temperature plasma (LD-LTP) ionization, demonstrating the integration of the complete workflow in RmsiGUI. The design of the Open LabBot and the software are released under open licenses to promote their use and adoption in the instrument developers’ community.

Experimental study on desulfurization at low temperature with plasma modified calcium-based adsorbent

Activated carbon and quicklime were used to prepare complex calcium based adsorbent for flue gas desulphurization. The desulfurization properties of adsorbent were analyzed on fixed bed. The results showed that the desulfurization effect of the composite adsorbent was best when the ratio of activated carbon to calcium was 1:2, the water heating time was 24 hours and heating temperature was 90 °C. At the same time, low temperature plasma technology is used to ionize the composite adsorbent, increase the number of surface chemical functional groups of the adsorbent, and then improve its desulfurization efficiency. The effect of modification time and power on desulfurization efficiency was studied. The results show that low temperature plasma ionization modification can obviously improve the desulfurization performance of composite adsorbent.

Effect of Ultrasonic Microdroplet Generation in the Low-Temperature Plasma Ionization-Mass Spectrometry

Low-temperature plasma (LTP) ionization is one of the ambient ionization methods typically used in mass spectrometry (MS) for fast screening of chemicals with minimal or no sample preparation. In spite of various advantages of LTP ionization method, including simple instrumentation and in-situ analysis, more general applications of the method are limited due to poor desorption of analytes with low volatilities and low ionization efficiencies in the negative ion mode. In order to overcome these limitations, an ultrasonic vibrator of a commercial hand-held humidifier was interfaced with an LTP ionization source, which generated microdroplets from sample solutions and assisted with LTP ionization. Ionization behaviors of various chemicals in microdroplet-assisted LTP (MA LTP) were tested and compared with typical LTP ionization from dried samples applied on a surface. MA LTP efficiently ionized small organic, amino, and fatty acids with low volatilities and high polarities, which were hardly ionized using the standard LTP method. Facile interaction of LTP with ultrafine droplets generated by ultrasonic resonator allows efficient ionization of relatively non-volatile and polar analytes both in the positive and negative ion modes.

Spray-inlet microwave plasma torch and low temperature plasma ionization for ambient mass spectrometry of agrochemicals

The unique ionization characteristics of plasma can be used in multimodal ion sources, which have expanded plasma-based ambient ionization mass spectrometry rapidly to accommodate a range of analytical applications.

Response in Ambient Low Temperature Plasma Ionization Compared to Electrospray and Atmospheric Pressure Chemical Ionization for Mass Spectrometry.

Modern technical evolution made mass spectrometry (MS) an absolute must for analytical chemistry in terms of application range, detection limits and speed. When it comes to mass spectrometric detection, one of the critical steps is to ionize the analyte and bring it into the gas phase. Several ionization techniques were developed for this purpose among which electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are two of the most frequently applied atmospheric pressure methods to ionize target compounds from liquid matrices or solutions. Moreover, recent efforts in the emerging field of “ambient” MS enable the applicability of newly developed atmospheric pressure techniques to solid matrices, greatly simplifying the analysis of samples with MS and anticipating, to ease the required or even leave out any sample preparation and enable analysis at ambient conditions, outside the instrument itself. These developments greatly extend the range of applications of modern mass spectrometry (MS). Ambient methods comprise many techniques; a particular prominent group is, however, the plasma-based methods. Although ambient MS is a rather new field of research, the interest in further developing the corresponding techniques and enhancing their performance is very strong due to their simplicity and often low cost of manufacturing. A precondition for improving the performance of such ion sources is a profound understanding how ionization works and which parameters determine signal response. Therefore, we review relevant compound characteristics for ionization with the two traditional methods ESI and APCI and compare those with one of the most frequently employed representatives of the plasma-based methods, i.e., low temperature plasma ionization. We present a detailed analysis in which compound characteristics are most beneficial for the response of aromatic nitrogen-containing compounds with these three methods and provide evidence that desorption characteristics appear to have the main common, general impact on signal response. In conclusion, our report provides a very useful resource to the optimization of instrumental conditions with respect to most important requirements of the three ionization techniques and, at the same time, for future developments in the field of ambient ionization.

Study of Photocatalytic Nano-Particle Effects on the Low Temperature Plasma Ionization Mass Spectrometry.

Although the low temperature plasma mass spectrometry (LTP-MS) is widely used as an analysis tool for many biochemical samples, its application window is somehow limited to the analytes of low molecular mass and high volatility. For this reason, there have been attempts to enhance the ionization/desorption efficiencies with extra heating, for instance. In this study, another enhancement method was suggested using the photocatalytic nano-particles (NPs). In order to assess the NP effects on the LTP-MS, two fatty acid ethyl ester samples of ethyl myristate and ethyl palmitate were used, and the NP of titanium dioxide (TiO2) was mainly employed. The results showed that the signal intensities of the LTP-MS were largely increased with the TiO2 addition for both samples. In addition, the cholesterol sample was analyzed usingthe TiO2 assisted LTP-MS, also resulting in the enhancement of the signal intensity. The overall results inferred that the photocatalytic NP confirmed its role as an effective assist tool forthe LTP-MS, especially suitable because of the facile method and the heat-free nature. Graphical Abstract ᅟ.

Analyte and matrix evaporability - key players of low-temperature plasma ionization for ambient mass spectrometry.

The introduction of ambient ionization at atmospheric pressure for mass spectrometry (AI-MS) attracted the interest of many researchers in the field and various ionization techniques have been described in recent years that allow a quick and easy-to-handle analysis of samples under ambient conditions without or with only minor sample preparation. Among those, plasma-based techniques including the low-temperature plasma probe require very little resources thereby providing great potential for implementation in mobile analytical devices. However, systematic studies on signal responsiveness with this technique, such as the influence of the analyte and matrix characteristics on relative signal intensity, are still rare. Therefore, we used a low-temperature plasma source based on dielectric barrier discharge with helium as process gas to assess influencing factors on signal intensity in mass spectrometry. Among 12 tested molecular descriptors, in particular a low vaporization enthalpy and a large molecular nonpolar surface area improve the relative signal intensity. In addition, we show that the impact of compound characteristics strongly outperforms the influence of simple sample matrices such as different organic solvents and water, with a weak trend that volatile solvents tend to decrease the signal responsiveness of the analytes. However, several specific solvent-analyte interactions occurred, which have to be considered in targeted applications of this method. Our results will help further in improving the implementation and standardization of low-temperature plasma ionization for ambient mass spectrometry and understanding the requirements and selectivity of this technique. Graphical abstract Influencing factors (analyte and matrix characteristics) on signal intensity in dielectric-barrier discharge plasma for ionization in mass spectrometry.

The requirements for low-temperature plasma ionization support miniaturization of the ion source.

Ambient ionization mass spectrometry (AI-MS), the ionization of samples under ambient conditions, enables fast and simple analysis of samples without or with little sample preparation. Due to their simple construction and low resource consumption, plasma-based ionization methods in particular are considered ideal for use in mobile analytical devices. However, systematic investigations that have attempted to identify the optimal configuration of a plasma source to achieve the sensitive detection of target molecules are still rare. We therefore used a low-temperature plasma ionization (LTPI) source based on dielectric barrier discharge with helium employed as the process gas to identify the factors that most strongly influence the signal intensity in the mass spectrometry of species formed by plasma ionization. In this study, we investigated several construction-related parameters of the plasma source and found that a low wall thickness of the dielectric, a small outlet spacing, and a short distance between the plasma source and the MS inlet are needed to achieve optimal signal intensity with a process-gas flow rate of as little as 10mL/min. In conclusion, this type of ion source is especially well suited for downscaling, which is usually required in mobile devices. Our results provide valuable insights into the LTPI mechanism; they reveal the potential to further improve its implementation and standardization for mobile mass spectrometry as well as our understanding of the requirements and selectivity of this technique. Graphical abstract Optimized parameters of a dielectric barrier discharge plasma for ionization in mass spectrometry. The electrode size, shape, and arrangement, the thickness of the dielectric, and distances between the plasma source, sample, and MS inlet are marked in red. The process gas (helium) flow is shown in black.

In vivo monitoring of nicotine biosynthesis in tobacco leaves by low-temperature plasma mass spectrometry

Low-temperature plasma (LTP) is capable of ionizing a broad range of organic molecules at ambient conditions. The coupling of LTP to a mass analyzer delivers chemical profiles from delicate objects. To investigate the suitability of LTP ionization for mass spectrometry (MS) based in vivo studies, we monitored the auxin-regulated nicotine biosynthesis in tobacco (Nicotiana tabacum) and evaluated possible biological effects. The measured nicotine concentrations in different experiments were comparable to literature data obtained with conventional methods. The observed compounds suggest the rupture of trichomes, and cell damage was observed on the spots exposed to LTP. However, the lesions only affected a negligible proportion of the leaf surface area and no systemic reaction was noted. Thus, our study provides the proof-of-concept for measuring the biosynthetic activity of plant surfaces in vivo.

Reactive low temperature plasma ionization mass spectrometry for the determination of organic UV filters in personal care products

Organic UV filters in personal care products (PCPs) have been persistently reported as a potential threat to human health. In order to guarantee consumers’ safety, the dose of these compounds in PCPs needs to be monitored. Here, a methodology based on reactive low temperature plasma ionization (LTP) mass spectrometry (MS) has been developed for the determination of common organic UV filters in PCPs including benzophenone-3, ethylhexyl dimethyl p-aminobenzoic acid, ethylhexyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, and ethylhexyl salicylate. The experiments were carried out in transmission geometry where the LTP ion source, samples loaded on a stainless steel mesh, and the MS inlet were aligned coaxially. Four chemicals, ammonia, ammonium formate, aniline, and methylamine were considered as reactive additives allowing reactions with the UV filters through different mechanisms. Methylamine-induced reactive LTP-MS showed the most prominent improvement on the detection of UV filter compounds. Compared to direct LTP-MS, the developed method improved the detection limits of UV filters more than 10 fold. Moreover, the method enabled fast semi-quantitative screening of UV filters in authentic PCPs. Concentrations of active ingredients in eight authentic PCPs as determined with reactive LTP-MS were found comparable to values offered by the cosmetic companies and corresponding HPLC data. The methodology provides high throughput analysis (70s per sample) and sensitive identification of organic UV filters. Lowest detectable concentrations ranged from 0.13µg/g for 4-methylbenzylidene camphor to 7.67µg/g for octocrylene in spiked cream. In addition, it shows the potential to be used as a screening tool for legal authentications of these chemicals in the future due to its semi-quantitative determination of UV filters in PCPs without tedious sample preparation and time-consuming chromatographic separation.

Real-Time Food Authentication Using a Miniature Mass Spectrometer.

Food adulteration is a threat to public health and the economy. In order to determine food adulteration efficiently, rapid and easy-to-use on-site analytical methods are needed. In this study, a miniaturized mass spectrometer in combination with three ambient ionization methods was used for food authentication. The chemical fingerprints of three milk types, five fish species, and two coffee types were measured using electrospray ionization, desorption electrospray ionization, and low temperature plasma ionization. Minimum sample preparation was needed for the analysis of liquid and solid food samples. Mass spectrometric data was processed using the laboratory-built software MS food classifier, which allows for the definition of specific food profiles from reference data sets using multivariate statistical methods and the subsequent classification of unknown data. Applicability of the obtained mass spectrometric fingerprints for food authentication was evaluated using different data processing methods, leave-10%-out cross-validation, and real-time classification of new data. Classification accuracy of 100% was achieved for the differentiation of milk types and fish species, and a classification accuracy of 96.4% was achieved for coffee types in cross-validation experiments. Measurement of two milk mixtures yielded correct classification of >94%. For real-time classification, the accuracies were comparable. Functionality of the software program and its performance is described. Processing time for a reference data set and a newly acquired spectrum was found to be 12 s and 2 s, respectively. These proof-of-principle experiments show that the combination of a miniaturized mass spectrometer, ambient ionization, and statistical analysis is suitable for on-site real-time food authentication.