Commercial Mass Spectrometer Research Articles

Collision cross-section measurements of small molecules via transient decay profiles observed in Orbitrap mass analyzers.

Collision cross section (CCS) of organic compounds can be measured via Fourier transform-based mass spectrometry (MS) by modeling the decay rate of transient signals in the analyzer. Deriving CCS values of low-mass molecules (mass < 2000 Da and CCS < 500 Å2) with Orbitrap MS is challenging due to their high axial frequencies and small absolute variances in cross-sectional profiles. Here, we acquired mass spectra of progressively more complex low-mass analytes using commercial Orbitrap mass spectrometers. The transient signals were processed using Fast Fourier transform (FFT) and short-time Fourier transform (StFFT) to derive decay constants of multiple select ionic species from a single MS full-scan experiment. Decay constants were translated into CCS values using at least two internal standards in the same mass spectrum. Our results suggest target ionic species should have high S/N in order to derive CCS values with ≤0.5% uncertainty. Limitations in the precision of CCS measurements reflect local space charge effects that disturb ion motion in the analyzer. The derived CCS values of polymer like fragments of Ultramark 1621 and small molecules such as individual protonated amino acids can achieve average ±1% error with selection of internal standards across a wide mass range. Future studies need to optimize the strategy to select internal standards in order to improve the precision and accuracy of CCS measurements for small molecules via Orbitrap MS.

Hardware and software solutions for implementing nanospray desorption electrospray ionization (nano-DESI) sources on commercial mass spectrometers.

Nanospray desorption electrospray ionization (nano-DESI) is an ambient ionization mass spectrometry imaging (MSI) approach that enables spatial mapping ofbiological and environmental samples with high spatial resolution and throughput. Because nano-DESI has not yet been commercialized, researchers develop their own sources and interface them with different commercial mass spectrometers. Previously, several protocols focusing on the fabrication of nano-DESI probes have been reported. In this tutorial, we discuss different hardware requirements for coupling the nano-DESI source to commercial mass spectrometers, such as the safety interlock, inlet extension, and contact closure. In addition, we describe the structure of our custom software for controlling the nano-DESI MSI platform and provide detailed instructions for its usage. With this tutorial, interested researchers should be able to implement nano-DESI experiments in their labs.

Infrared Photodissociation Spectroscopy of Water-Tagged Ions with a Widely Tunable Quantum Cascade Laser for Planetary Science Applications.

This work presents a benchtop method for collecting the room temperature gas phase infrared (IR) action spectra of protonated amino acids and their isomers. The adopted setup uses a minimally modified commercial electrospray ionization linear ion trap mass spectrometer (ESI-LIT-MS) coupled to a broadband continuous wave (cw) quantum cascade laser (QCL) source. This approach leverages messenger assisted action spectroscopic techniques using water-tagged molecular ions with complex formation, irradiation, and subsequent analysis, all taking place within a single linear ion trap stage. This configuration thus circumvents the use of multiple mass selection and analysis stages, cryogenic buffer cells, and complex high-power laser systems typically called upon to execute these techniques. The benchtop action spectrometer is used to collect the 935-1600 cm-1 (6.2-10.7 μm) IR action spectrum of a collection of amino acids and a dipeptide with results cross referenced against literature examples obtained with a free electron laser source. Recorded IR spectra are used for the analysis of binary mixture samples composed of constitutional isomers α-alanine and β-alanine with ratios determined to ∼4% measurement uncertainty without the aid of a front-end separation stage. This turn-key QCL-based approach is a major step in showing the viability of tag-based action spectroscopic techniques for use in future in situ planetary science sensors and general analytical applications.

Data Acquisition and Intraoperative Tissue Analysis on a Mobile, Battery-Operated, Orbitrap Mass Spectrometer.

Mass spectrometry has been increasingly explored in intraoperative studies as a potential technology to help guide surgical decision making. Yet, intraoperative experiments using high-performance mass spectrometry instrumentation present a unique set of operational challenges. For example, standard operating rooms are often not equipped with the electrical requirements to power a commercial mass spectrometer and are not designed to accommodate their permanent installation. These obstacles can impact progress and patient enrollment in intraoperative clinical studies because implementation of MS instrumentation becomes limited to specific operating rooms that have the required electrical connections and space. To expand our intraoperative clinical studies using the MasSpec Pen technology, we explored the feasibility of transporting and acquiring data on Orbitrap mass spectrometers operating on battery power in hospital buildings. We evaluated the effect of instrument movement including acceleration and rotational speeds on signal stability and mass accuracy by acquiring data using direct infusion electrospray ionization. Data were acquired while rolling the systems in/out of operating rooms and while descending/ascending a freight elevator. Despite these movements and operating the instrument on battery power, the relative standard deviation of the total ion current was <5% and the magnitude of the mass error relative to the internal calibrant never exceeded 5.06 ppm. We further evaluated the feasibility of performing intraoperative MasSpec Pen analysis while operating the Orbitrap mass spectrometer on battery power during an ovarian cancer surgery. We observed that the rich and tissue-specific molecular profile commonly detected from ovarian tissues was conserved when running on battery power. Together, these results demonstrate that Orbitrap mass spectrometers can be operated and acquire data on battery power while in motion and in rotation without losses in signal stability or mass accuracy. Furthermore, Orbitrap mass spectrometers can be used in conjunction to the MasSpec Pen while on battery power for intraoperative tissue analysis.

Charge Detection Mass Spectrometry for Megadalton Polymer Characterization and Measurement of Electrospray-Generated Charged Droplet Dynamics with a New "Direct Visualization of the Rayleigh Limit" Approach to Aid in m/z Calibration.

A charge detector has been constructed and mounted inside the vacuum housing of a commercial mass spectrometer (Micromass-Waters Quattro I, Waters Corp., Manchester, UK). The in-house built single-pass charge detector is composed of a designed, complete electronics system that includes a low-noise charge amplifier. Communication to the data acquisition system was enabled, and analog and digital filters were devised, followed by their tuning and programming. Data treatment scripts for data analysis and plotting were automated, and the assembled system was calibrated and tested. The instrument has an acquisition speed of ∼200 detection events/s, and it permits detection down to ∼510 charges (= three times RMS noise) for a single measured particle. The charge detector was employed to determine the oligomer distribution of a megadalton polymer, polyethylene glycol (PEG). The PEG size distribution exhibits a maximum at ∼ m/z 5910 with the oligomeric population mass distribution peaking near 4.45 MDa. In studies of methanol droplet dynamics, "charge vs time-of-flight" plots enabled clear visualization of the zone near the Rayleigh limit to droplet charging. The highest population of methanol droplets near the Rayleigh limit carried 5000-7000 charges. This corresponds to droplet weights of 10-20 GDa, with the high-end tail extending above 70 GDa. This visualization of the most highly charged droplets (that bear numbers of charges near those defined by the Rayleigh equation) was exploited as a calibration aid for our charge detector, which lacks a means of precisely defining ion energy. A maximum m/z error of -12.3% was calculated for the method, i.e., less than the potential error in assigning the true level of charging of the most highly charged droplets relative to the Rayleigh limit. With these limitations in mind, the introduced method will provide a new means for aiding the calibration of m/z values in charge detectors.

Detection of 238Pu at picogram quantities by laser resonance ionization mass spectrometry

Based on the laser resonance ionization mass spectrometry (LRIMS) developed in the laboratory, a preliminary method was established to determine Pu isotope ratios. A three-color-three-photon resonance ionization scheme was confirmed, and the laser wavelengths of each excitation/ionization step were λ1 = 586.654 nm, λ2 = 606.181 nm and λ3 = 642.722 nm. The selective ionization of 238Pu/238U was realized by testing the Pu and U mixed sample, a selectivity ratio of over 107 was obtained. More effective electrothermal atomization of Pu was implemented by loading graphene oxide solution on the Pu sample surface, and the total detection efficiency of ∼40 ng Pu sample was above 3 × 10−4, which was three orders of magnitude higher than the efficiency of the unloaded graphene oxide solution Pu sample. Results showed that the relative standard deviation of 238Pu/239Pu ratio was ∼0.20%, indicating that LRIMS could effectively avoid the isobaric interference of 238U faced by other commercial mass spectrometers such as TIMS and ICP-MS, and could achieve precise measurement of 238Pu/239Pu ratio.

Dipole and quadrupole resonance excitation in linear quadrupoles.

In the development of commercial quadrupole mass spectrometers, there is an interest in improving the performance characteristics such as transmission, resolution, and mass range. In particular, parametric and dipolar resonance excitation of trapping ions are used for linear quadrupole mass filters. Theoretical methods and numerical simulation of ion trajectories were applied for study of ion-optical properties. The review is devoted to description of different excitation methods to improve QMF performance and consists of three parts. The first part presents the results of a linear ion trap simulation for various operating conditions and excitation methods. The second part considers the effects of dipole excitation (DE) on the performance of the quadrupole mass filter. The last part analyzes the formation of stability islands by different methods of quadrupole excitation. To date conditions of mass separation in quadrupole mass filters with sin wave supply were described for stability islands of the first and third stability regions formed by quadrupole and DE. By complicating the electronics such methods allow to overcome the destructive influence of electric field distortions and obtain a resolving power and ion transmission efficiency comparable with commercial devices. At quadrupole resonance excitation by a two-frequency signal, it is possible to reduce the length of electrodes three times without losses in resolution and transmission, which reduces the cost of rod set production with micrometer accuracy. Dipole resonance excitation allows controlling the shape of the mass peak by changing amplitude and phase of the auxiliary AC signal. The main factors affecting the resolving power of a linear ion trap are described theoretically. The numerical modeling results are confirmed by experiment.

Light-Induced Orthogonal Fragmentation of Crosslinked Peptides.

Crosslinking mass spectrometry provides pivotal information on the structure and interaction of proteins. MS-cleavable crosslinkers are regarded as a cornerstone for the analysis of complex mixtures. Yet they fragment under similar conditions as peptides, leading to mixed fragmentation spectra of the crosslinker and peptide. This hampers selecting individual peptides for their independent identification. Here, we introduce orthogonal cleavage using ultraviolet photodissociation (UVPD) to increase crosslinker over peptide fragmentation. We designed and synthesized a crosslinker that can be cleaved at 213 nm in a commercial mass spectrometer configuration. In an analysis of crosslinked Escherichia coli lysate, the crosslinker-to-peptide fragment intensity ratio increases from nearly 1 for a conventionally cleavable crosslinker to 5 for the UVPD-cleavable crosslinker. This largely increased the sensitivity of selecting the individual peptides for MS3, even more so with an improved doublet detection algorithm. Data are available via ProteomeXchange with identifier PXD040267.

Novel Isotope Dilution High-Performance Liquid Chromatography Quadrupole–Linear Ion Trap Tandem Mass Spectrometry Method for the Determination of Five Steroid Hormones in Human Serum

Accurate measurement of endogenous steroid hormones in serum is a powerful tool for understanding the status of human adrenal diseases. Isotope dilution–liquid chromatography–tandem mass spectrometry is the most commonly used method for determination of steroids in serum. In this study, we used a laboratory-constructed quadrupole-linear ion trap (Q-LIT) tandem mass spectrometer to develop a new method for the quantification of five steroid hormones in serum. A simple and efficient pretreatment was improved, wherein the serum was extracted once by a mixed solvent of 1.0 mL of ethyl acetate and n-hexane. Using the optimized method, the regression coefficients of the calibration curves were all higher than 0.99, the limits of detection were from 0.31 to 1.25 ng mL−1, and the limits of quantification were between 1.00 and 2.50 ng mL−1. The intra-day (n = 3) relative standard deviations ranged from 4.24% to 13.79%, and the inter-day (n = 3) relative standard deviations from 3.99% to 11.43%. After internal standard correction, the relative recoveries of all steroids were from 86.08% to 106.60%. Twenty-two serum samples were analyzed by Q-LIT, which was compared with commercial triple quadrupole mass spectrometer. The results of the instruments had high consistency. Therefore, Q-LIT accurately quantified steroid hormones in human samples and may be used for clinical diagnosis and monitoring of hormone-dependent diseases.

Dopant ionization and efficiency of ion and electron ejection from helium nanodroplets.

Photoionization spectroscopy and mass spectrometry of doped helium (He) nanodroplets rely on the ability to efficiently detect ions and/or electrons. Using a commercial quadrupole mass spectrometer and a photoelectron-photoion coincidence spectrometer, we systematically measure yields of ions and electrons created in pure and doped He nanodroplets in a wide size range and in two ionization regimes-direct ionization and secondary ionization after resonant photoexcitation of the droplets. For two different types of dopants (oxygen molecules, O2, and lithium atoms, Li), we infer the optimal droplet size to maximize the yield of ejected ions. When dopants are ionized by charge-transfer to photoionized He nanodroplets, the highest yield of O2 and Li ions is detected for a mean size of ∼5×104 He atoms per nanodroplet. When dopants are Penning ionized via photoexcitation of the He droplets, the highest yield of O2 and Li ions is detected for ∼103 and ∼105 He atoms per droplet, respectively. At optimum droplet sizes, the detection efficiency of dopant ions in proportion to the number of primary photoabsorption events is up to 20% for charge-transfer ionization of O2 and 2% for Li, whereas for Penning ionization it is 1% for O2 and 4% for Li. Our results are instrumental in determining optimal conditions for mass spectrometric studies and photoionization spectroscopy of molecules and complexes isolated in He nanodroplets.

Analytical performance of single particle aerosol mass spectrometer for accurate sizing and isotopic analysis of individual particles

The commercial Hexin Single particle aerosol mass spectrometer (SPAMS) has been widely used for environmental aerosol monitoring and source apportionment. However, particle size measurement is easily affected by environment pressure fluctuation and sampling orifice clogging. The capability for quantitative analysis is poor, and few isotope measurement has been reported. This paper aims to evaluate the analytical performance of SPAMS and extend its application. First, the flight time of standard particles having different densities and sizes was measured under various conditions (aerodynamic lens upstream pressure and carrier gas). We proposed a universal method for particle size calibration, measurement and correction, taking into account the effects of lens geometry (acceleration nozzle diameter), particle parameters (density, diameter, and shape factor), and operating conditions (lens upstream pressure and carrier gas). Then, isotope measurement was performed when introducing a solution droplet containing a single element. Metal oxide and metal cluster ions were observed in the mass spectrum, indicating incomplete ionization of the sample droplet. The mass discrimination effect was carefully evaluated to correct the measured isotope ratio. Results show that the achievable accuracy of the corrected isotope ratio for elements investigated was 5%. The instrumental performance was relatively poor for elements having great ionization potential or bond energy. Finally, Ag/Eu2O3 suspension and yellow cake/ethanol suspension were analyzed for size, elemental and isotopic analysis. We confirmed that the mass discrimination effect during suspension introduction could be corrected using the mass discrimination correction factor obtained during solution introduction. The Ag, Eu and U in these suspension particles were all found to be at natural abundance. The uranium in the yellow cake was identified as sodium duranyate (Na2U2O7) with volumetric equivalent diameter of approximately 65 nm. The work presented here is beneficial for instrument improvement and wide application.

Mass calibrants for positive chemical ionization-high resolution mass spectrometry (CI-HRMS) for the identification of unknown compounds using accurate mass measurements.

Gas Chromatography-Electron Ionization-Mass Spectrometry (GC-EI-MS) is still the most routinely performed method for metabolite profiling as compared to other hyphenated techniques. But when it comes to identification of unknown compounds, information on the molecular weight is not readily available because the molecular ion is not always found with electron ionization (EI). Thus, the use of chemical ionization (CI) is envisaged that commonly produces the molecular ion; in combination with accurate mass measurement, this technique would further allow for calculation of sum formulas of those compounds. However, for proper accuracy of analysis, a mass calibrant is needed. We set out to find a commercially available reference material with mass peaks that would qualify the substance as mass calibrant under CI conditions. Six commercially available mass calibrants, FC 43, PFK, Ultramark 1621, Ultramark 3200F, Triton X-100, and PEG 1000, were tested under CI conditions to understand their fragmentation behavior. Our findings indicate that Ultramark 1621 and PFK best fit the expectations of a mass calibrant for HRMS analysis whereby PFK provided a fragmentation pattern similar to EI outcomes thus enabling the use of mass reference tables commonly provided within commercial mass spectrometers. On the other hand, Ultramark 1621 is a mixture of fluorinated phosphazines that shows stable fragment intensities.

Differences in the internal energies of ions in electrospray ionization mass spectrometers equipped with capillary-skimmer and capillary-RF lens interfaces.

Small metabolites are commonly analyzed using electrospray ionization mass spectrometry (ESI-MS). Although the protonated form of a compound of interest is typically the target ion in ESI-MS, the protonated forms of small metabolites occasionally undergo fragmentation during ion transmission from ambient conditions to vacuum conditions, hindering the unambiguous identification of analyte molecules. To estimate the fragmentation efficiency during ESI processes, the internal energy distribution of the ions (P(E)) must be evaluated. The common approach for the P(E) evaluation is the survival yield method, which uses thermometer ions. In this study, the P(E) of ions produced by an ESI source in a commercial triple quadrupole mass spectrometer equipped with a capillary-skimmer and capillary-RF lens interfaces was evaluated using benzyl ammonium thermometer ions. Furthermore, this study proposes the use of 3-(aminomethyl)indole and related compounds, which have the lowest Eapp values among the reported thermometer ions, to obtain P(E) values of the ions more accurately. Results showed that P(E) strongly depends on whether a capillary-skimmer interface or capillary-RF lens interface was used for ion transport to the vacuum. ESI-MS with a capillary-skimmer interface provided a considerably lower and narrower P(E) of ions than that with a capillary-RF lens interface, thereby producing intact protonated molecules without significant fragmentation of most small metabolites. However, ESI-MS equipped with capillary-RF lens interfaces provided a higher efficiency of ion transmission than ESI-MS equipped with a capillary-skimmer interface, allowing for highly sensitive analysis of metabolites.

Analysis of Lipid Contents in Human Trabecular Meshwork Cells by Multiple Reaction Monitoring (MRM) Profiling Lipidomics.

Lipids are among the major constituents of cells and play many important cellular functions. Lipid levels in the trabecular meshwork (TM) aqueous humor outflow pathwayplay an important role in the maintenance of aqueous humor drainage and intraocular pressure (IOP) homeostasis. Therefore, it is important to characterize the changes in the lipid contents in the aqueous humor outflow pathway tissues to better understand their functional significance in the maintenance of IOP. The multiple reaction monitoring (MRM)-based profiling aids in the analysis of the metabolome as a collection of functional groups and is utilized as an exploratory metabolomics and lipidomics approach. The MRM-based profiling utilizes tandem mass spectrometry experiments carried out on a commercial triple quadrupole mass spectrometer with three aligned quadrupole mass filters (Q1, Q2, and Q3). This screening methodology can be utilized for targeted lipidomics screening. This chapter focuses on the methodology for isolation and culturing of the TM cells, lipid extraction, and the MRM-based lipidomics approach with data analysis.

Sequential measurement of 13 C, 15 N, and 34 S isotopic composition on nanomolar quantities of carbon, nitrogen, and sulfur using nano-elemental analysis/isotope ratio mass spectrometry.

We report modifications to a commercial elemental analyzer-isotope ratio mass spectrometer that permit high-precision isotopic analysis of nanomoles of carbon (C), nitrogen (N), and sulfur (S) on a single sample without chemical or cryogenic trapping of gases. The sample size required for measurement by our system is about two orders of magnitude less than that for conventional analyses. Our system builds on the analytical advancements offered by the EA IsoLink IRMS System and employs simple modifications to reduce the diameter of the flow path (reactors, water trap, and transfer lines), enhance peak separation (gas chromatography capillary column), and improve sample transfer to the ion source of the mass spectrometer (reduced flow rates). Conventional precision (<0.2‰) can be achieved down to c. 500 nmol C, N, and S for samples analyzed without modification of the commercial system. Further reduction in sample size (<50 nmol C, N, and S) was achieved with minor modifications. There is a significant carbon blank and a small nitrogen blank that can be measured directly and a sulfur blank that can be calculated using regression. Only 30 nmol of N, 22 nmol of C, and 12 nmol of S are needed to achieve better than 1‰ precision (1σ) from a single measurement. Larger samples and more replicate measurements provide better precision. The nano-EA method described here reduces sample size requirements by two orders of magnitude compared to traditional approaches and improves the accuracy and precision of isotope measurements on sample sizes less than 1 μmol. These advancements simplify the analytical technique and broaden the range and type of samples amenable to EA analysis.

Analysis of unknown fentanyl analogs using high resolution mass spectrometry with mass defect filtering

Drug overdoses in the United States have increased over the past several years due to the increase in the highly potent fentanyl and fentanyl analogs on the illicit drug market. Fentanyl analogs are created by altering the functional groups on the core fentanyl molecule. These molecules are continuously being tweaked which creates a challenge for forensic laboratories trying to identify these substances with traditional methods. Current screening methods of immunoassay or mass spectrometry target known standards for analysis and may not identify new analogs. Herein, we demonstrate a screening methodology that takes advantage of the mass accuracy afforded by a commercial high resolution mass spectrometer. A three-step, post-acquisition data analysis process identifies fentanyl analogs through mass defect filtering of unfragmented data, common fragments, and mass defect filtering of the fragmented data. Using this method, analysts can identify potential fentanyl analog peaks in the spectra and can then perform further structural elucidation and identification.

Energy-Resolved Ion Mobility Spectrometry: Composite Breakdown Curves for Distinguishing Isomeric Product Ions.

Identification of lipopeptides (LpAA) synthesized from bacteria involves the study of structural characterization. Twenty LpAA have been characterized using commercial tandem high-resolution mass spectrometers in negative electrospray, employing nonresonant excitation in "RF only" collision cells and generally behave identically. However, [LpAA-H]- (AA = Asp or Glu) shows surprising fragmentation pathways, yielding a complementary fatty acid carboxylate and dehydrated amino acid fragment anions. In this study, the dissociation mechanisms of [C12Glu-H]- were determinate using energy-resolved mass spectrometry (ERMS). Product ion breakdown profiles are, generally, unimodal with full width at half-maximum (fwhm) increasing as product ion m/z ratios decrease, except for the two product ions of interest (fatty acid carboxylate and dehydrated glutamate) characterized by broad and composite profiles. Such behavior was already shown for other ions using a custom-built guided ion beam mass spectrometer. In this study, we investigate the meaning of these particular profiles from an ERMS breakdown, using fragmentation mechanisms depending on the collision energy. ERMS on line with ion mobility spectrometry (IMS), here called ER-IMS, provides a way to probe such questions. Broad or composite profiles imply that the corresponding product ions may be generated by two (or more) pathways, resulting in common or isomeric product ion structures. ER-IMS analysis indicates that the fatty acid carboxylate product ion is produced with a common structure through different pathways, while dehydrated glutamate has two isomeric forms depending on the mechanism involved. Drift time values correlate with the calculated collision cross section that confirms the product ion structures and fragmentation mechanisms.

A review on ion mobility mass spectrometry

Mass Spectrometry can be coupled with ion mobility to get results that cannot be obtained by alone mass spectrometry. This coupled instrument can be used for knowing the separation of isomers, isobars, and conformers, the reduction of chemical noise, and the measurement of ion size. It divides ions into families of ions as well as ions with the same charge and similar structural properties. The four ion mobility separation techniques currently applied to mass spectrometry are described in this article. Low-resolution mobility separation is demonstrated by AIMS. Offering continuous ion monitorings are DMS and FAIMS. TWIMS is a novel IMS technique that has good sensitivity and is well integrated into a commercial mass spectrometer while having modest resolving power. In this review it includes that Many researches has used this technique has it gives results in millisecond and its low cost operation.it has major drawback of contamination of compounds due to atmospheric pressure, complex spectra and interferences aredue to wide spread of ionization.it is not suitable for Non-volatile compound and the repoducubility is1-2%.

Focusing Plasma Desorption/Ionization Mass Spectrometry.

A plasma-based source named focusing plasma desorption/ionization (FPDI) is described, which applies a high direct current voltage between a metal wire inside a polymeric hollow truncated cone and a piece of a one-sided coated conducting paper substrate. The conducting paper acts as both the counter electrode and the sample carrier. Upon the generation of a visible plasma beam, it would directly ionize the samples spotted on the conducting paper substrate or located around the plasma beam. The signal intensity of target analytes in mass spectrometric analysis is dependent highly on whether the conducting paper substrate is grounded or not, the type of conducting paper substrate, the inside diameter of the polymeric hollow truncated cone tip, the metal wire tip-to-polymer tip distance, the polymer tip-to-paper substrate distance, the applied voltage, and the helium flow rate. Based on the experimental observation, a plausible mechanism is proposed for the generation of the plasma beam from FPDI. Compared to the available low-temperature plasma, flowing atmospheric-pressure afterglow, and helium plasma ionization sources, FPDI has demonstrated higher sensitivity and better compatibility with commercial mass spectrometers without any extra power supplies. As a proof of concept, FPDI coupled with a mass spectrometer has also been applied for the discrimination of different brands of gasoline and determination of solid tablets and pesticides with limits of detection in the range of 2.2 to 30.7 ng mL-1.

Building Australia's first mass spectrometer: Recognising the achievements of J. Roger Bird.

Following the birth of the field of mass spectrometry at the end of World War I, it was several decades before the first commercial mass spectrometers became available. In the interim, many physicists interested in the nature of matter, and their application to studies in nuclear physics, constructed their own. A young physics postgraduate student, John Roger Bird, was the first to do so in Australia. This article describes his efforts and achievements, featuring technical blueprints, photographs of the instruments and early data, in long overdue recognition of Bird's work at the University of Melbourne.