Miniature Mass Spectrometer Research Articles

A review of the development and application of space miniature mass spectrometers

This article reviews the recent development and application of four types of space miniature mass spectrometers including magnetic sector mass spectrometer, quadrupole mass spectrometer, ion trap mass spectrometer and time-of-flight mass spectrometer. The advantages and the disadvantages of such mass spectrometers are briefly discussed. Finally, the expectations for improved properties and development trends of these mass spectrometers are presented.

Looking for a wider audience

Mass spectrometry is a go-to method for determining which molecules are in a sample. If security officers are faced with an unknown, possibly dangerous, substance, they don’t want to waste time sending samples to a lab and waiting for mass spec results, however. They’d rather be able to take a portable mass spec into the field to get answers quickly. Efforts to miniaturize mass spectrometers are by no means new. Researchers have been working to fit these powerful instruments into small packages for decades. They’ve succeeded in making small systems for particular applications, but they haven’t succeeded as much in reaching a broader audience. Miniature mass specs face the challenge of “false expectations” from users, says R. Graham Cooks, a chemistry professor at Purdue University and leader in the field. If people expect a miniature mass spectrometer to give them the same quality data as a high-end lab instrument, they’re

Detecting traces of fentanyl in the field

It’s not uncommon for David DiGregorio and his team to get called in when first responders find a substance they can’t identify at a scene. A suspicious white powder in the restroom of a fast-food restaurant, for instance, has triggered a request for DiGregorio, the director of hazardous materials emergency response for the Massachusetts Department of Fire Services. Officials on the scene wanted to know: Is it safe to allow other patrons into that bathroom? If the powder contained trace levels of fentanyl, an opioid that’s normally cut into other drugs or filler powders, the team wouldn’t have been able to detect it before November of last year. That’s when the hazmat responders got miniature mass spectrometers from 908 Devices, a miniature mass spec company based in Boston. They’ve provided feedback to the company to improve the libraries and sampling techniques used in its instruments for detecting fentanyl and its

Direct Biological Sample Analyses by Laserspray Ionization Miniature Mass Spectrometry.

With improved performances, miniature mass spectrometers are becoming suitable for more practical applications. At the same time, the coupling of an approximate ionization source is essential in terms of minimizing sample preparation and broadening the range of samples that could be analyzed. In this study, an atmospheric pressure laserspray ionization (AP-LSI) source was coupled with our home developed miniature ion trap mass spectrometer. The whole system is compact in size, and biological samples could be directly analyzed with minimum sample preparation. Direct detections of peptides, proteins, drugs in whole blood, and urine could be achieved with high sensitivity. The analyses of tissue sections were demonstrated, and different regions in a tissue section could be differentiated based on their lipid profiles. Results suggest that the coupling of AP-LSI with miniature mass spectrometer is a powerful technique, which could potentially benefit target molecule analysis in biological and medical applications.

Implementation of Precursor and Neutral Loss Scans on a Miniature Ion Trap Mass Spectrometer and Performance Comparison to a Benchtop Linear Ion Trap.

Implementation of orthogonal double resonance precursor and neutral loss scans on the Mini 12 miniature rectilinear ion trap mass spectrometer is described, and performance is compared to that of a commercial Thermo linear trap quadropole (LTQ) linear ion trap. The ac frequency scan version of the technique at constant rf voltage is used here because it is operationally much simpler to implement. Remarkably, the Mini 12 shows up to two orders of magnitude higher sensitivity compared to that of the LTQ. Resolution on the LTQ is better than unit at scan speeds of ~ 400Th/s, whereas peak widths on the Mini 12, on average, range from 0.5 to 2.0Th full width at half maximum and depend heavily on the precursor ion Mathieu q parameter as well as the pump down time that precedes the mass scan. Both sensitivity and resolution are maximized under higher pressure conditions (short pump down time) on the Mini 12. The effective mass range of the product ion ejection waveform was found to be 5.8Th on the Mini 12 in the precursor ion scan mode vs. that of 3.9Th on the LTQ. In the neutral loss scan mode, the product ion selectivity was between 8 and 11Th on the Mini 12 and between 7 and 8Th on the LTQ. The effects of nonlinear resonance lines on the Mini 12 were also explored. Graphical Abstract ᅟ.

Magnetron-like miniature ion source

This paper describes a new type of a miniature ion source (about 0.05 cm3), partially based on the construction of a magnetron but made with the use of the MEMS (Micro-Electro-Mechanical System) technology. Two configurations of the device have been tested: two-electrode, working in low vacuum (from 70 to 0.02 hPa) and three-electrode, operating in a wide range of pressure (from 70 to 10−5 hPa). The gas ionization process takes place only for certain electrode spacings and proper electrodes polarization. For optimal geometry and supply conditions electrons are “trapped” and circulate inside the microdevice, which increases the probability of their collisions with gas particles even in high vacuum. The three-electrode ion source can by further use as a part of a miniature mass spectrometer as well as an ion-sorption micropump or pressure microgauge.

Mini 2000: A Robust Miniature Mass Spectrometer with Continuous Atmospheric Pressure Interface

A miniature mass spectrometer with continuous atmospheric pressure interface (CAPI) developed previously in our lab has proved to have high stability and rapid analysis speed. With the aim of achieving smaller size, better performance and easier maintenance, in this study, an upgraded miniature mass spectrometer with CAPI was developed, in which all components were optimized and redesigned into a packaged unit. Using a more powerful pumping system, better analytical performances were obtained for this system. The miniature mass spectrometer has the capability to perform tandem mass spectrometry, and could be coupled with ambient ionization sources for analysis of different samples. Good stability (signal relative standard deviation, RSD < 5%), high sensitivity (limit of detection, LOD 10 ng/mL), better than unit mass resolution, and a broad mass range (from 150 Da to 2000 Da) were obtained. Integrated with a tablet computer for system control, the miniature mass spectrometer has dimensions of 38 cm × 23 cm × 34 cm (length × width × height), and is 13 kg in total weight. The whole system is powered by an adapter with a power consumption of 200 watts in total.

Proof-of-concept: Interfacing the liquid sampling-atmospheric pressure glow discharge ion source with a miniature quadrupole mass spectrometer towards trace metal analysis in cell culture media

The facile interfacing of the LS-APGD to a commercial, small-format quadrupole MS holds promise for at-bioreactor elemental analysis.

Field optimization of toroidal ion trap mass analyzers using toroidal multipoles

Toroidal ion traps show promise for miniaturized mass spectrometers. However, because of the geometry of the trap, there remains a lack of understanding about the electric field and its effect on the motion of trapped ions. As an approach to this problem, solutions to the Laplace equation in a toroidal coordinate system can be used to characterize the electric potential distribution. The symmetric 2nd order solution of the second kind, or toroidal quadrupole, was previously explored for an ion trap. Non-ideal features in the stability diagram were similar to that for conventional ion traps with higher-order field contributions. To eliminate or reduce these non-ideal features, other solutions to the Laplace equation, including higher-order solutions, can be added to the toroidal quadrupole. The toroidal hexapole (T3) improves the stability diagram by reducing the jagged features at the stability apex and reducing the βr + 2βz = 2 resonance line when the A3 coefficient of the toroidal hexapole is in the range of 2.75. The βr = 1/2 resonance line is eliminated by the A3 coefficient of 1 or greater for the toroidal hexapole. The βr = 2/3 resonance line is not present in the viewed voltage range when the A3 coefficient is between 3.5 and 4.75, and the βr + βz = 1 resonance line becomes evident in this same range with the toroidal hexapole contribution is greater than 4.25. The toroidal octopole (T4) and decapole (T5) give no clear trend in variation of the non-ideal features in the stability diagram. The electrode geometry and stability diagram were very sensitive to small additions of the toroidal dipole (T1). The addition of a toroidal hexapole component to the toroidal quadrupole provides improvement in ion trapping, and is expected to play an important role in optimizing the performance of all types of toroidal ion trap mass spectrometers.

Rapid identification of regulated organic chemical compounds in toys using ambient ionization and a miniature mass spectrometry system

Rapid, on-site analysis was achieved through significantly simplified operation procedures for a wide variety of toy samples (crayon, temporary tattoo sticker, finger paint, modeling clay, and bubble solution) using a miniature mass spectrometry system with ambient ionization capability. The labor-intensive analytical protocols involving sample workup and chemical separation, traditionally required for MS-based analysis, were replaced by direct sampling analysis using ambient ionization methods. A Mini β ion trap miniature mass spectrometer was coupled with versatile ambient ionization methods, e.g. paper spray, extraction spray and slug-flow microextraction nanoESI for direct identification of prohibited colorants, carcinogenic primary aromatic amines, allergenic fragrances, preservatives and plasticizers from raw toy samples. The use of paper substrates coated with Co3O4 nanoparticles allowed a great increase in sensitivity for paper spray. Limits of detection as low as 5μgkg-1 were obtained for target analytes. The methods being developed based on the integration of ambient ionization with miniature mass spectrometer represent alternatives to current in-lab MS analysis operation, and would enable fast, outside-the-lab screening of toy products to ensure children's safety and health.

Recent developments of miniature ion trap mass spectrometers

With outstanding analytical performance and portability, miniature mass spectrometer is one of the most powerful tools for in-situ analysis. The miniaturization of mass spectrometers has lasted for more than ten years, during which a number of miniature mass spectrometers employing different techniques have been developed. Small-in-size, working at relatively high pressure region and capable of performing tandem mass spectrometry, ion trap is the most widely used mass analyzer in miniature mass spectrometer systems. The recent development of miniature ion trap mass spectrometer systems in the last ten years was reviewed in this paper. These instruments adopt different atmospheric pressure interfaces (APIs), which are membrane inlets (MIs), discontinuous atmospheric pressure interface (DAPI) and continuous atmospheric pressure interface (CAPI). This review emphasizes on the mini mass spectrometry (MS) system that can be handheld by one person, but not the field-able ones that are too large to be hand-portable.

Development of a low power miniature linear ion trap mass spectrometer with extended mass range

A miniaturized ion trap mass spectrometer with continuous atmospheric pressure interface was built, which could be used in conjunction with internal ionization (in-vacuum plasma ionization) and external ionization (electrospray ionization). To improve its mass range, a supplemental AC signal frequency scan mode was performed for this miniature mass spectrometer, in which the fundamental RF signal was remained constant with an amplitude as low as several hundreds volts. Experiments showed that the upper limit of the mass range can be extended to 2500 Da for the miniature mass spectrometer developed in this work, and the power consumption can be reduced by 2/5, while maintaining good balance with performance parameters such as stability, sensitivity, and resolution. Due to the improvement in mass range and significant reduction in energy consumption compared with the instrument using the traditional resonant ejection mode, the scan method developed in this work is helpful to promote the miniature design of mass spectrometers for field analysis and space exploration.

Developing a Vacuum Electrospray Source To Implement Efficient Atmospheric Sampling for Miniature Ion Trap Mass Spectrometer.

The performance of a miniature mass spectrometer in atmospheric analysis is closely related to the design of its sampling system. In this study, a simplified vacuum electrospray ionization (VESI) source was developed based on a combination of several techniques, including the discontinuous atmospheric pressure interface, direct capillary sampling, and pneumatic-assisted electrospray. Pulsed air was used as a vital factor to facilitate the operation of electrospray ionization in the vacuum chamber. This VESI device can be used as an efficient atmospheric sampling interface when coupled with a miniature rectilinear ion trap (RIT) mass spectrometer. The developed VESI-RIT instrument enables regular ESI analysis of liquid, and its qualitative and quantitative capabilities have been characterized by using various solution samples. A limit of detection of 8 ppb could be attained for arginine in a methanol solution. In addition, extractive electrospray ionization of organic compounds can be implemented by using the same VESI device, as long as the gas analytes are injected with the pulsed auxiliary air. This methodology can extend the use of the proposed VESI technique to rapid and online analysis of gaseous and volatile samples.

Using miniature MS system with automatic blood sampler for preclinical pharmacokinetics study.

Preclinical pharmacokinetic studies are an essential part of modern drug development. In this work, we explored a new solution with onsite analysis using a miniature MS system, which can significantly improve the efficiency of the preclinical study.Materials & methods: A miniature mass spectrometer was used with an automatic blood sampler for onsite quantitation of drug compounds in whole blood samples. Slug-flow microextraction was used to replace the in-lab sample preparation. Animal studies were carried out using two drug compounds, using the auto sampler to take blood samples at preprogrammed time points. The miniature MS system was used to obtain drug concentrations, which were subsequently used to calculate the pharmacokinetic parameters.

Proof of Concept Coded Aperture Miniature Mass Spectrometer Using a Cycloidal Sector Mass Analyzer, a Carbon Nanotube (CNT) Field Emission Electron Ionization Source, and an Array Detector.

Despite many potential applications, miniature mass spectrometers have had limited adoption in the field due to the tradeoff between throughput and resolution that limits their performance relative to laboratory instruments. Recently, a solution to this tradeoff has been demonstrated by using spatially coded apertures in magnetic sector mass spectrometers, enabling throughput and signal-to-background improvements of greater than an order of magnitude with no loss of resolution. This paper describes a proof of concept demonstration of a cycloidal coded aperture miniature mass spectrometer (C-CAMMS) demonstrating use of spatially coded apertures in a cycloidal sector mass analyzer for the first time. C-CAMMS also incorporates a miniature carbon nanotube (CNT) field emission electron ionization source and a capacitive transimpedance amplifier (CTIA) ion array detector. Results confirm the cycloidal mass analyzer's compatibility with aperture coding. A >10× increase in throughput was achieved without loss of resolution compared with a single slit instrument. Several areas where additional improvement can be realized are identified. Graphical Abstract ᅟ.

A dual-source miniature mass spectrometer with improved sensitivity

Previously, we have reported the development of a miniature mass spectrometer with a continuous atmospheric pressure interface, whose sensitivity was sacrificed due to the limited gas flow rate. In this study, a circular lens was designed and integrated on the ion transfer pathway between the two pumping stages, and a ten-fold sensitivity improvement could be achieved when coupling with external ionization sources. Besides the capability of working with ionization sources in the atmosphere, there is also an in-vacuum plasma ionization source, so that both volatile and non-volatile samples could be analyzed. A 10 ppbv detection sensitivity was achieved for dimethyl methyl phosphonate (DMMP) in air using the plasma ionization source. Furthermore, the miniature mass spectrometer was also demonstrated for the direct analyses of progesterone in drinking water and atrazine in soil samples using paper spray and syringe spray, respectively.

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.

Simulation of the influence of constant uniform magnetic field on a miniature LIT mass spectrometer.

In this paper, the effects of constant uniform magnetic fields on a miniature linear ion trap mass spectrometer with hyperbolic electrodes are simulated using SIMION 8.0 3D software. Magnetic fields in different directions have different effects on the trajectories of the trapped ions and the shape of the ion cloud. When the magnetic field is applied in the z-direction, namely the ion injection direction, the magnetic field will cause the ions focusing to the z-axis, and exert a compression effect on the ion cloud. When the magnetic field is applied in the x-y plane, the original ion cloud will be expanded due to the action of the applied magnetic field, and the ion cloud plane after expansion is always perpendicular to the direction of the magnetic field. The discovery of influence field of magnetic will bring some useful inspiration for the improvement of ion trapping efficiency, mass resolution, sensitivity and trapping capacity, which is conductive to the performance enhancement utilization of magnetic field, even in the industrial application development and other aspects.

Development of Electrospray/Photoionization Miniature Ion Trap Mass Spectrometer

Abstract An electrospray/ultraviolet lamp dual-source ion trap mass spectrometer was developed for the rapid detection of gas and liquid samples. A discontinuous atmospheric pressure sampling system was used in the instrument, in which both the electrospray ions and gaseous analytes were sampled and transferred by a pinch valve device. The two ionization sources used here were generally suitable for different kinds of analytes and provide complementary applications. Electrospray was used for the ionization of polar compounds in solution, while the UV ionization source was mainly applied to the analysis of gaseous organic compounds. A variety of samples such as anisole, toluene, 2,4-dimethylaniline, arginine, reserpine and aspartame were employed to test the performance in different working mode of the instrument. The result showed that the two sources was suitable for ionization of different samples, and different types of molecular ions were generated when analyzing 2,4-dimethylaniline. Two ionization sources could be used alternately or simultaneously without interference with the other and the working mode could also be switched to fit the application requirements. Dual-source configuration was an effective way to extend the applications for miniature mass spectrometers. It did not significantly increase the size of the instrument, but provided more versatile analysis to meet the need for the measurement of different types of samples.

Simultaneous Online Monitoring of Multiple Reactions Using a Miniature Mass Spectrometer.

Advances in chemical sampling using miniature mass spectrometer technology are used to monitor slow reactions at a frequency of ca. 180 h-1 (on the Mini 12) with no sample carryover and with inline derivatization in the case of poorly ionizing compounds. Moreover, we demonstrate high reproducibility with a relative error of less than 10% for major components. Monitoring is enabled using a continuous-flow nanoelectrospray (CF-nESI) probe contained in a custom-built 3D-printed rotary holder. The holder position is automatically set using a stepper motor controlled by a microcontroller. Reaction progress of up to six reactions, including hydrazone formation and Katritzky transamination, can be monitored simultaneously without carryover for several hours.