Financial support was provided by the Competence Center for Materials Science and Technology (CCMX, Project NanoAir), the Swiss National Science Foundation (Project 139136), the Swiss Nanoscience Institute (Argovia, Project NanoFil), and the Swiss Competence Center for Bioenergy Research (SCCER BIOSWEET). The authors thank Albert Schuler for his support in operating the TGA, and Adelaide Calbry-Muzyka for reviewing this manuscript.

1. RDD-SMPS-ICPMS Setup
<ol>
	<li>Coupling strategy of the RDD-SMPS-ICPMS setup 
	NOTE: In order to couple the different instruments, i.e. RDD, SMPS and ICPMS, and to control the different gas flows, some modifications in the instrumental arrangements are needed. The main steps of the coupling concept are summarized here:
	<ol>
		<li>Use conductive tubing with inner/outer diameters 6.0/12.0 mm (carbon impregnated silicone tubing) to connect the different instrumental parts.</li>
		<li>Install the Rotating Disk Diluter between the aerosol source and the Differential Mobility Analyzer, or DMA, where the particle size classification takes place. Split the classified aerosol at the DMA outlet in two fractions. One will be aspirated by the Condensation Particle Counter, or CPC. The other is guided towards the Inductively Coupled Plasma Mass Spectrometer, or ICPMS (Figure 1).</li>
		<li>Use a mass flow controller (MFC) and a filter, such as a High-Efficiency Particulate Air filter (HEPA), to provide the RDD with particle-free dilution argon.</li>
		<li>Add another filter at the RDD outlet for the excess raw gas (QRDD out). Check the performance of all the filters in use from time to time while using the CPC.</li>
		<li>Use another MFC and filter to adjust the sheath gas flow (Qsheath) introduced to the DMA.</li>
		<li>To adjust the DMA excess gas flow (QDMA exc), mount a filter, MFC, and vacuum pump in series at the DMA outlet.</li>
		<li>Connect an additional MFC and filter to add particle free air (QCPC air) to the CPC, as makeup flow to reduce the amount of classified aerosol (QCPC class), consumed by the CPC. 
		NOTE: This is because the CPC actively aspirates a flow defined by a critical orifice and an external pump, which is about 1 L/min. The classified flow rate at the ICP inlet (QICP in) is the difference between the flow rate at the DMA outlet (Qclass) and QCPC class.</li>
	</ol>
	</li>
</ol>
2. Measurement Protocol for RDD-SMPS-ICPMS
NOTE: Before tuning the SMPS-ICPMS parameters, the flows used for the aerosol generator must be set. Here, the procedure of using liquid and solid samples is described.
<ol>
	<li>Example of aerosol sources
	<ol>
		<li>Using aerosol generator for liquids and suspensions
		<ol>
			<li>For an example of using an aerosol generator for a suspension, prepare a zinc oxide (ZnO) suspension from a commercial ZnO nanopowder (e.g. with a nominal diameter of 50 nm) and poly-acrylic acid as stabilizer for the nanoparticles. Dilute the prepared suspension to obtain a ZnO concentration of approx. 30 &#181;g/mL. This concentration is chosen because it will lead to a good ICPMS signal later, with all the gas flows applied.</li>
			<li>For the second measurement prepare an aqueous sodium chloride (NaCl) solution with a concentration of 200 &#181;g/mL.
			<ol>
				<li>First, fill the suspension or solution into the bottle and mount it on the aerosol generator.</li>
			</ol>
			</li>
			<li>Use the aerosol generator to generate an aerosol from the salt solution or the particle suspension, and to remove the water from the particles in the silica gel drier.
			<ol>
				<li>Set the compressed air valve of the aerosol generator slightly above 1 bar. Adjust the This results in an aerosol flow behind the diffusion drier to aboutof approximately 1 L/min. Finally, connect the outlet of the drier to the RDD inlet.</li>
			</ol>
			</li>
		</ol>
		</li>
		<li>Using thermogravimeter or a tubular furnace 
		NOTE: As an example for applying the RDD-SMPS-ICPMS in measuring emissions from thermal processes, a copper chloride (CuCl2) sample is analyzed. Two aerosol sources are used, namely a TGA and a tubular furnace. In both cases, the reactive gas (e.g. O2), which is used for the thermal process, is mixed with argon to the appropriate ratio in order to prevent nucleation and condensation. In this work only the measurement procedure and representative data from a TGA experiment are presented.
		<ol>
			<li>First, tare the empty TGA crucible. Weigh 50 mg of CuCl2 powder and place it in a crucible.</li>
			<li>Adjust one MFC for the reactive gas (O2) to about 20 mL/min.</li>
			<li>Set the flow of the protective gas (argon) to about 80 mL/min. At the TGA outlet, add an argon flow of about 900 mL/min to get a total flow of about 1 L/min (i.e. the sum of the flows of O2, protective argon and added argon). If the RDD pump is used, adjust the MFC to reach the required flow.</li>
			<li>Set the desired temperature program (25 &#176;C for 18 min and 450 &#176;C for 15 min).</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Setting the flows 
	NOTE: To achieve a stable operation of the RDD-SMPS-ICPMS setup, all the gas and aerosol flows should be adjusted carefully as described below. In this section, an example of a set of parameter values for adjusting the RDD, SMPS and ICPMS are given. Another set of parameters is possible; the procedure will however remain the same. The flow abbreviations used are listed in Figure 1. In the following steps use a flowmeter, such as a flow calibrator, to measure the different gas and aerosol flows before starting the measurement.
	<ol>
		<li>First set the argon sheath flow at the DMA inlet to 3 L/min.</li>
		<li>Set the temperature of the RDD heating block to 80 &#176;C, and that of the evaporation tube to 350 &#176;C.</li>
		<li>Adjust the mass flow controller of the dilution argon in order to obtain 0.6 L/min as flow of the diluted sample at the outlet of the rotating disk diluter (Qsample). The ratio 0.6/3 of the sheath gas to the sample gas is chosen to cover a particle size ranging from about 14 to about 340 nm.</li>
		<li>Then, carefully adjust the excess gas mass flow controller (QDMA exc) to achieve a classified aerosol flow of 0.6 L/min (Qclass), the same flow rate as that of the diluted polydispersed aerosol at the DMA inlet (Qpoly).</li>
		<li>Next, Place the flow calibrator between DMA and CPC, and adjust the CPC makeup air flow, to reduce the flow rate of classified aerosol aspirated by the CPC to 0.18 L/min. This corresponds to 30% of Qclass.</li>
		<li>Check the remaining flow of classified aerosol to ensure that 0.42 Liter per min are directed to the ICPMS, i.e. 70% of the classified aerosol (Qclass). Slight change of this flow can be corrected by fine-tuning the MFC of the DMA excess gas again.</li>
	</ol>
	</li>
	<li>Setting the SMPS software
	<ol>
		<li>Next, calculate the dynamic viscosity and the mean free path of argon at ambient temperature and pressure23. Enter both values in the SMPS software.</li>
		<li>In the SMPS software, set the up and down scan durations of the DMA scanning cycle to 150 s and 30 s (i.e. 1 DMA cycle = 1 scan = 180 s).</li>
		<li>In the SMPS software, set the DMA maximum voltage to 4.5 kV to cover the PSD interval ranging from about 14 to about 340 nm. 
		NOTE: A voltage maximum of 10 kV is normally used in air-operated SMPS. Due to the lower dielectric strength of argon relative to that of air, the limit should be set lower in this application, since otherwise electric arcing would occur, leading to instrument damage and signal errors.</li>
	</ol>
	</li>
	<li>Setting the ICPMS
	<ol>
		<li>Remove the conventional introduction system of liquid samples to introduce dry aerosol directly into ICPMS. Add a conductive tube between the respective port of DMA outlet and the ICPMS. Use this tube for xenon (Xe), with a concentration of about 100 ppmv in argon matrix, to optimize the ICPMS plasma prior to each measurement and to control the plasma stability during the measurement.</li>
		<li>Maintain the Xe flow constant for all measurements (e.g. at 4 mL/min) and tune the other parameters in the ICPMS software, including ICP dilution gas and sampling depth, to achieve a fixed Xe intensity. 
		NOTE: The main ICPMS tuning parameters are listed in Table 1. The parameters to be tuned prior to each measurement are indicated in the last column.</li>
		<li>Set the SMPS and ICPMS acquisition time to cover the desired total duration of the aerosol measurement (e.g., for 10 SPMS scan, set the ICPMS acquisition time to at least 30 min).</li>
		<li>After setting the gas flows and the SMPS and the ICPMS parameters run the two instruments manually at the same time. In the case of the TGA, acquire SMPS and ICPMS blank signals at 25 &#176;C for 18 min (6 scans). In the case of the suspension or liquid sample, acquire blank signals during 2 scans of 6 min with the disk rotation speed set to zero. Then set the dilution factor of the RDD to the desired value by adjusting the disk rotation speed manually. With the current configuration, 100% rotating speed corresponds to a dilution factor of 14.9.</li>
	</ol>
	</li>
	<li>Data analysis 
	NOTE: ICPMS measures the ion intensity per unit time (unit: count per second, or cps) for each m/z. This intensity is proportional to the analyte mass. SMPS data represent the number-weighted PSD of classified aerosol (PSDn) entering the DMA (unit: 1/cm3), based on the number concentrations determined by the CPC behind the DMA. To compare both ICP and SMPS signals, the volume-weighted PSD (PSDv) must be calculated. The following calculations and corrections should be made:
	<ol>
		<li>Export the raw signal intensities versus time for each m/z from the ICPMS data, and the PSDn- determined by the SMPS software &#8211; as a function of the particle diameter (dp). From the SMPS raw data, export the particle diameter and the corresponding scanning time. Use the latter in order to correlate the ICPMS measurement time with the particle diameter (see below). 
		NOTE: The SMPS software must consider that the aerosol flow at the DMA outlet is split, and only 30% of the classified particles reach the CPC. This can be achieved by multiplying the counting efficiency values &#8211; stored in a separate table as type-specific CPC characteristics &#8211; by a factor of 0.3.</li>
		<li>Since the desired information is not primarily the particle concentration between RDD and DMA, but that at the RDD inlet, multiply the measured concentrations by the RDD dilution factor, i.e. 14.9 in the current configuration.</li>
		<li>To calculate volume-weighted data from the original number-weighted SMPS data, multiply the recorded concentrations of PSDn by the volume V(dP) of the measured particles6 (V(dP)= (&#960;/6)&#8729;dP3).</li>
		<li>Calculate the ICPMS net signal by subtracting the background signal from the raw ion signal for each isotope. Then, multiply the net signal by the inverse single charge probability 1/p+1(dp) to get the corrected ICP intensity, which is approximately proportional to the concentration at the DMA inlet and hence at the RDD inlet (assuming no particle losses between RDD inlet and ICPMS or CPC inlets).
		<ol>
			<li>Calculate the probability of particles to carry one elemental positive charge by using the Wiedensohler approximation24. For the SMPS data processed by the SMPS software, the correction for this charge probability is normally implemented in the software.</li>
		</ol>
		</li>
		<li>For a given SMPS scan, plot the SMPS particle concentration or the ICPMS intensity as a function of particle diameter in an x-y diagram. In the case of a steady-state aerosol, use the same type of diagram to present the concentration or intensity averaged over several scans.</li>
		<li>For a series of scans, use 2D surface or 3D diagrams to plot the SMPS concentration or ICPMS intensity as functions of diameter and time. In the case of thermal processes, if a temperature program is used, substitute the time by the corresponding temperature values. 
		NOTE: Moreover, the calculations needed for ICPMS and SMPS data to make such plots can be automated using calculation software like MATLAB or Igor Pro, which allows for obtaining robust final results in a short time.</li>
	</ol>
	</li>
</ol>

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The authors declare no competing financial interests.

Compared with the state-of-the-art existing analytical methods for aerosols, such as particle sizers, the RDD-SMPS-ICPMS combination is not only able to simultaneously acquire chemical and size information, but the time-resolved ICPMS signal also allows the determination of each element&#39;s contribution in the overall PSD. However, only particles with a diameter below 500 nm can be measured by the current argon-operated SMPS-ICPMS. Furthermore, for a complete characterization of aerosol particles, other offline techniques are needed to determine other properties, including the morphology and the molecular structure.
The NaCl measurement is a simple example showing that a steady-state process can be controlled/monitored well with the coupled SMPS-ICPMS system. This setup can also be used in such experiments as an online analytical tool to reveal the effects of different experimental parameters on the properties of the generated particles. Any change in the particle size, and in the particle or elemental concentration, such as in the case of the thermal treatment of CuCl2 sample, can be tracked online by SMPS-ICPMS.
On the other hand, the SMPS-ICPMS combination allows not only to measure, but also to distinguish between gas and particle species. Indeed, the part of the signal related to the particulate matter can be easily distinguished from that of gaseous compounds, because the ICPMS signal of the latter covers the entire size range and does not follow a distribution shape such as that of the signal related to particles. This is due to the fact that the SMPS scanning has no effect on gaseous species, and the ICPMS measures the total intensity of a given isotope. This behavior is demonstrated by measuring Cl, which evaporates not only as particles, but also as gaseous species (Figure 4D-4E). Indeed, thermodynamic calculations show that under oxidizing conditions CuCl2 is evaporated at about 450 &#176;C as Cl2 gas and as condensable species CuCl2, Cu3Cl3 and Cu4Cl4 (data not shown).
Furthermore, using the ICPMS without SMPS offers the possibility to measure the overall ICPMS signal originating either from gaseous or particulate species. Using this arrangement for the measurement of CuCl2 evaporation (Figure 4F), for example, shows that the stoichiometry between the evaporated Cu and Cl does not change during the heating period, because of the similar signal shape. In addition, the gaseous species can be exclusively measured by the same setup by mounting a particle filter at the RDD outlet.
In the measurement protocol there are two critical points. On the one hand, the lower ICPMS intensity curve, compared to PSDv at large particle diameter range (e.g. in Figure 2B), can be explained by the fact that the consideration of multiple particle charges is not yet implemented in the data evaluation procedure (ongoing work). While the single-charge correction gives a good correlation between SMPS and ICPMS data when measuring small particles (up to 200 nm), correction for multiple charges on large particles should be established and implemented to improve the quality of the resulting information for particles above 200 nm. Another explanation of this effect could be that the larger particles are not completely decomposed and ionized in the plasma.
The second critical point is the choice of the appropriate RDD dilution factor. Indeed, like the analysis of liquid samples, the ICPMS intensity level of the different isotopes depends on the corresponding sensitivity. The Cu signal for example is about three orders of magnitude higher than that of Cl. Therefore, an appropriate value of the aerosol dilution must be set considering the ICPMS sensitivity of the measured elements. This presents a limitation of multi-element analysis for aerosols. However, the aerosol dilution value can be changed during the same experiment if the process of aerosol generation is known. For example, the dilution factor can be lowered during the period when a low particle amount is generated. Nevertheless, feeding highly particle-loaded aerosols into the DMA should be avoided to protect the CPC and the ICPMS instrumentation. In summary, depending on the sampled aerosol, a compromise between RDD dilution, matrix loading, and ICPMS sensitivity to the isotopes of interest should be found. Moreover, the time resolution of the SMPS-ICPMS setup is limited by the SMPS scan duration, which is in the range of a few minutes. However, for a fixed or narrow range of particles size, the time resolution can be enhanced.
Developing quantification methods for the overall setup is still needed (ongoing work). For thermal processes, a TGA can be used as a tool for quantification25. The quantification of liquids or suspensions can be made using appropriate standard solutions. Furthermore, designing a recirculation concept for argon, operating the DMA with air and exchanging this to argon &#8211; e.g. by means of a gas exchange device26 &#8211; would allow the use of higher DMA voltage and hence an increase in the measured particle range. Finally automating the setting of the different parameters and merging the needs of SMPS and ICPMS into a single concept regarding the operating condition will reduce substantially the steps of the measurement protocol. These steps help to make the SMPS-ICPMS a powerful online setup for quantitative or qualitative analyses of different kinds of aerosols generated from liquid, suspension, or emission sources.

In numerous fields, the characterization of particles in aerosols and suspensions &#8211; including the determination of chemical composition and size distribution &#8211; is an important issue. A variety of analytical techniques to determine particle properties is used in different environmental, industrial and research applications, such as measuring/monitoring air-borne or combustion-emitted particles, characterizing synthesized engineered nano-objects, and studying their health and environmental effects.
Size information of gas-borne particles and particles in suspensions is conventionally analyzed by different particle sizers, such as an Aerodynamic Particle Sizer (APS), Dynamic Light Scattering devices (DLS), or a Scanning Mobility Particle Sizer (SMPS)1,2,3,4,5. The latter &#8211; well-established aerosol measurement tool &#8211; consists of two parts, a Differential Mobility Analyzer (DMA) and a Condensation Particle Counter (CPC). Both instruments are mounted in series. The first one allows the classification of the aerosol particles according to their mobility diameters in an air stream by varying the voltage between two electrodes6. In the CPC, entering nanoparticles act as condensation nuclei, &#34;large&#34; droplets are formed, and then they are optically counted6. The SMPS output data represent size-resolved number information about the measured particles and are given as Particle Size Distributions (PSD).
On the other hand, the chemical characterization of gas-borne particles and particles in suspensions is usually performed offline7. An appropriate collection and sample preparation procedure is required prior to the analysis. Such offline investigations usually include the application of a spectroscopic technique, such as Inductively Coupled Plasma Mass Spectrometry (ICPMS). This is an established method in element and trace-element analysis of liquid samples with very high sensitivity and low detection limits8. In ICPMS, an argon plasma serves to dry and decompose introduced samples into atomic ions. These are then classified according their mass to charge ratio (m/z) and finally counted in analog or pulsed mode. Besides liquid samples, this technique is also used for gas and particle analysis. For example, gas can be directly introduced into the ICPMS and analyzed9,10,11. In speciation analysis, a Gas Chromatograph (GC) coupled to ICPMS is used to separate and detect volatile compounds12. ICPMS was further developed to so-called single particle ICPMS (sp-ICPMS) in order to characterize monodisperse particles in suspensions13,14. Other surface and/or bulk analytical techniques are used either to achieve a complete characterization, and/or to gain more information about the particle characteristics. Imaging techniques, such as Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), are widely used for this purpose15,16,17.
To simultaneously gain time-resolved chemical and size information, two different analytical techniques, such as SMPS and a plasma spectrometric technique, can be combined in one setup18. This online measurement concept can avoid problems related to sample collection, preparation and offline analysis procedure. A short overview of previous attempts to develop such a combined setup was reported by Hess et al.19.
In this work, a detailed description of a combined SMPS-ICPMS measuring arrangement and procedure is given. A Rotating Disk Diluter (RDD) is used as the introduction interface. The development of this hyphenated technique and three application studies can be found in the literature19,20,21. Figures of merit given by Hess et al.20 show that the performance of the developed SMPS-ICPMS instrumentation is comparable to that of the separate state-of-the-art systems. This study is complementary to the previous publications19,20,21 and gives a laboratory practice describing how this setup can be used. Example applications on aerosols from two different sources are shortly described, to show the versatility of the coupled system.
Before describing the measurement protocol, it is worth summarizing the individual components and the coupling strategy of the hyphenated setup. A more detailed description can be found elsewhere19. The main components of the coupled setup are: an aerosol source, RDD, DMA, CPC, and ICPMS.
To generate dried aerosol particles from a suspension or liquid solution, an aerosol generator equipped with a nozzle and a silica gel drier is used. A detailed description can be found elsewhere19. To investigate thermal processes, a Thermogravimetric Analyzer TGA (or a tubular furnace) is utilized.
The RDD is used for the aerosol sample introduction22. It consists of a heatable steel block equipped with two channels, and a rotating disk featuring several cavities. The channels are flushed with dilution gas and raw aerosol from the aerosol source. Depending on the gas flows and the disk rotation speed, a certain amount of raw aerosol is added to the dilution gas, resulting in a defined dilution ratio. Argon is used as dilution gas, because of the low air tolerance of the ICPMS. However, the DMA voltage limit should be set lower than that of air-operated DMA, in order to avoid electric arcing. Since the flow of diluted sample aerosol at the RDD outlet can be precisely controlled independently of the raw aerosol flow, the RDD sampling concept can be used for different aerosol sources. A heated tube (up to 400 &#176;C) is installed between RDD and SMPS, to evaporate volatile particles, and/or to further dilute the aerosol. This step is needed to achieve good reproducibility when processing samples containing organic matter. However, this may also trigger chemical reactions. Pyrolysis, for instance, starts at much lower temperatures and may decompose not only particles but also induce some chemical reactions. The SMPS used in this work consists of a DMA tube (similar to long DMA; see Materials table), and a commercial CPC. Before entering the DMA, the diluted aerosol must pass a radioactive source, called an aerosol neutralizer, in order to establish a known charge equilibrium (assuming a Boltzmann charge distribution)6. The particles are then classified according to their mobility diameter by varying the voltage at given DMA sheath and aerosol gas flows. The flow split at the DMA outlet is done such that 30% of the aerosol are directed to the CPC, the other 70% to the ICPMS. The number concentration of the classified particles is determined by the CPC. The other aerosol portion is analyzed by a commercial ICPMS instrument, allowing the elemental analysis of the aerosol-loaded particles. Since no liquids are investigated, the conventional sample introduction system is removed and the DMA outlet is directly connected to the ICPMS. A second RDD and another air-operated commercial SMPS are used as reference instruments to validate the PSD measured by the SMPS-ICPMS coupled setup. The RDD-SMPS reference system is connected to the raw aerosol outlet of the RDD of the coupled system.

<table><tbody><tr><td>ICPMS</td><td>Agilent Technologies, USA</td><td>7700x</td><td>Inductively Coupled&lt;br/&gt; Plasma Mass Spectrometer</td></tr><tr><td>DMA tube</td><td></td><td></td><td>similar to 3081 long DMA&lt;br/&gt; from TSI</td></tr><tr><td>Aerosol Neutralizer</td><td>TSI Inc., USA</td><td></td><td>85Kr radiation source</td></tr><tr><td>CPC</td><td>TSI Inc., USA</td><td>3010</td><td>Condensation Particle&lt;br/&gt; Counter</td></tr><tr><td>RDD</td><td>Matter Aerosol AG, Switzerland</td><td>MD193E</td><td>Rotating Disk Diluter;</td></tr><tr><td>Evaporation Tube</td><td>Matter Aerosol AG, Switzerland</td><td>ASET 15-1</td><td>Heated Tube</td></tr><tr><td>Aerosol Generator</td><td>Topas GmbH, Germany</td><td>ATM 220</td><td>aerosol generator</td></tr><tr><td>Silica Gel Drier</td><td>Topas GmbH, Germany</td><td>DDU570/H</td><td>silica gel diffusion drier</td></tr><tr><td>TGA</td><td>Mettler-Toledo Internat. Inc., CH</td><td>TGA/DCS1</td><td>Thermogravimetric analyzer</td></tr><tr><td>Gilibrator 2</td><td>Sensidyne, USA</td><td></td><td>primary flow calibrator</td></tr><tr><td>MFC</td><td>Sierra Instruments Inc., USA</td><td>Smart-Trak 50</td><td>mass flow controller</td></tr><tr><td>MFC</td><td>Brooks Instrument, Netherlands</td><td>4850</td><td>mass flow controller</td></tr><tr><td>MFC</td><td>Bronkhorst AG, Netherlands</td><td>F-201C-FAC-33-V</td><td>mass flow controller</td></tr><tr><td>In-Line Filter</td><td>Headline Filters, UK</td><td>DIF-LN30</td><td>disposable in-line filter</td></tr><tr><td>HEPA Filter</td><td>MSA (Mine Safety Appliances), USA</td><td>H cartridge #95302</td><td>High-Efficiency Particulate&lt;br/&gt; Air&lt;br/&gt; &amp;nbsp;</td></tr><tr><td>Conductive tubing</td><td>Advanced Polymers Ltd&lt;br/&gt; Worthing, UK.</td><td></td><td>carbon impregnated silicone&lt;br/&gt; tubing, inner/outer&lt;br/&gt; diameters 6.0/12.0 mm</td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>ZnO</td><td>Auer-Remy</td><td>5810MR, 1314-13-2</td><td>Nanopowder, 50 nm</td></tr><tr><td>NaCl</td><td>Merck</td><td>106406</td><td>Powder (&gt;99.99%)</td></tr><tr><td>CuCl&lt;sub&gt;2&lt;/sub&gt;</td><td>Merck</td><td>102733</td><td>Powder (&gt;99.0%)</td></tr><tr><td>Poly-Acrylic Acid</td><td>SigmaAldrich</td><td>535931</td><td>solution (50 wt. % in H&lt;sub&gt;2&lt;/sub&gt;O)</td></tr></tbody></table>

a practical guide on coupling a scanning mobility sizer and inductively coupled plasma mass spectrometer (smps-icpms)

A large variety of analytical methods are available to characterize particles in aerosols and suspensions. The choice of the appropriate technique depends on the properties to be determined. In many fields information about particle size and chemical composition are of great importance. While in aerosol techniques particle size distributions of gas-borne particles are determined online, their elemental composition is commonly analyzed offline after an appropriate sampling and preparation procedure. To obtain both types of information online and simultaneously, a hyphenated setup was recently developed, including a Scanning Mobility Particle Sizer (SMPS) and an Inductively Coupled Plasma Mass Spectrometer (ICPMS). This allows first to classify the particles with respect to their mobility diameter, and then to determine their number concentration and elemental composition in parallel. A Rotating Disk Diluter (RDD) is used as the introduction system, giving more flexibility regarding the use of different aerosol sources. In this work, a practical guide is provided describing the different steps for establishing this instrumentation, and how to use this analysis tool. The versatility of this hyphenated technique is demonstrated in example measurements on three different aerosols generated out of a) a salt solution, b) a suspension, and c) emitted by a thermal process.

In the first example, the setup is used as tool to measure online particles generated from a ZnO suspension (Figure 2). As can be seen in Figure 2A-2B, the PSDv appears shifted towards larger particles when compared to PSDn. Moreover, at large particle diameters, the ICPMS intensity curve lies slightly below the curve detected by SMPS. In the second example, the particles were generated from an aqueous NaCl solution (200 &#181;g/mL) using the same aerosol generator (Figures 3A-3C). The ICPMS and SMPS signals do not show a substantial change with time, and the time-resolved signal of sodium correlates well to the PSDv during the entire measuring period. Unlike Zn in the previous example, Na has a relatively high ICPMS background signal, resulting in a noisier signal than that of the concentrations recorded by the SMPS. As in the ZnO suspension sample, the mode of the PSDn lies at a lower particle diameter than that of the PSDv. Since the generated particles are NaCl particles, the behavior of the Cl signal is like that of Na and correlates well with the volume-related SMPS data (data not shown).
In the last example, the results of the thermal treatment of a CuCl2 sample by using the TGA are presented. Figure 4A shows the PSDn recorded for particles down to 20 nm at the beginning of the TGA heating (at about 21 min on time axis, i.e. at the beginning of the 7th SMPS scan). Afterwards the particle concentration in PSDn reaches a steady state when the temperature is maintained constant and the particles cover a size range between 60 and 250 nm. A slight increase is observed in the particle size after the 11th SMPS scan (at about 30 min on time axis). Considering PSDv (Figure 4B), the contribution of the different particle sizes is quite different to that of PSDn, and with the PSDv becoming high mainly between 150 and 330 nm. The ICPMS signal of Cu shown in Figure 3C correlates well with PSDv. Figure 4D-4E shows the corrected and raw 35Cl intensity during the up and down scans, respectively. After the starting point of the heating period, beside the intensity corresponding to particles of chlorine species, constant Cl intensity covers the particle size range was measured (in the time interval 18 to 33 min, i.e. from the 7th to the 11th SMPS scan). This is due to the evaporation of Cl gaseous species. The chlorine particulates are recorded in the same size range as copper, namely in particles with diameters above 150 nm. Another experiment using the same sample (CuCl2) is performed without SMPS and by using only the TG-RDD-ICPMS setup. Here the ICPMS signal of the non-classified aerosol particles is measured (Figure 4F). Similar to the case of SMPS-ICPMS, an increase of both signals (Cl and Cu) in the last scans can be observed.
The results reported in this work demonstrate the versatile use of the coupled SMPS-ICPMS system with different aerosol sources. In the examples presented the correlation between the time-resolved ICPMS signal of Cu and PSDv is obvious. For an aerosol loaded with different particles, the contribution of each element in the overall PSDv is determined by the ICPMS signals. Moreover, the example of NaCl shows that keeping the experimental conditions constant results in a steady state time-resolved signal. The SMPS-ICPMS setup allows to monitor any change in elemental and/or size concentration of the generated aerosol. For instance, the higher signal of PSDn in the CuCl2 experiment (Figure 4C) may be caused by the abrupt start of the heating process. Meanwhile, the increase in SMPS and ICPMS signals during the final scans can be explained by the change of the temperature gradient of the CuCl2 sample with time, which changes the total amount of the material reaching the evaporation temperature. Finally, considering the SMPS output data, the concentration in PSDv is shifted towards larger particle size than in PSDn. This is because the signal is multiplied with the 3rd power of the particle diameter to convert PSDn to PSDv, resulting in stronger weighting of large particles in the volume than in the number regime.
<img alt="Figure 1" src="/files/ftp_upload/55487/55487fig1.jpg" /> 
Figure 1: Coupling Strategy for the Different Instrumental Parts in RDD-SMPS-ICPMS Setup. Nomenclature: Qsample: flow from the aerosol generator; Qdilut: RDD dilution argon flow, QRDD out: raw aerosol flow out of the RDD; Qpoly: flow of diluted polydisperse aerosol at the DMA inlet; Qsheath: DMA sheath gas flow; Qclass: flow of classified aerosol at the DMA outlet; QDMA exc: DMA gas excess flow; QCPC class: fraction of Qclass guided into the CPC; QCPC air: additional air flow for the CPC; QCPC in: total flow entering the CPC; QICP in: fraction of Qclass guided into the ICPMS; QXe: xenon flow; MFC: mass flow controller. <a href="http://cloudflare.jove.com/files/ftp_upload/55487/55487fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/55487/55487fig2.jpg" /> 
Figure 2: SMPS-ICPMS Data of the ZnO Suspension. (A) Number-based PSD (PSDn), recorded by SMPS. (B) The corresponding volume-based PSD (PSDv) and corrected 66Zn signal, detected by ICPMS. The three signals are an average over 4 SMPS scans. <a href="http://cloudflare.jove.com/files/ftp_upload/55487/55487fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/55487/55487fig3.jpg" /> 
Figure 3: SMPS-ICPMS Data of the Measurement of the NaCl Solution. (A) ICP corrected signal of 23Na. (B) PSDv. (C) Corresponding PSDn. The SMPS concentrations and ICPMS intensities are plotted as functions of diameter and time. <a href="http://cloudflare.jove.com/files/ftp_upload/55487/55487fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" src="/files/ftp_upload/55487/55487fig4.jpg" /> 
Figure 4: SMPS-ICPMS Data from Measuring CuCl2 Evaporation by Using the TGA. (A) 2D plot of PSDn (B) 2D plot of PSDv. (C) 2D plot of 63Cu ICPMS signal. (D) 2D plot of 35Cl ICPMS signal. (E) Non-corrected raw 35Cl ICPMS signal vs. time. (F) ICPMS signal of 65Cu and 35Cl recorded during thermal treatment of CuCl2 by using TG-RDD-ICPMS setup (without SMPS). In both experiments (with and without SMPS) blank signals at 25 &#176;C are measured for about 18 min (6 SMPS scans), before starting and maintaining the heating period (for 15 min) at 450 &#176;C. The recording of SMPS-ICPMS signals was started at the same time as that of the TGA signals and was stopped 1 scan after switching it off (resulting in a total of 12 SMPS scans). <a href="http://cloudflare.jove.com/files/ftp_upload/55487/55487fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Parameter</td>
			<td>Value</td>
			<td>To be tuned</td>
		</tr>
		<tr>
			<td>Power</td>
			<td>1350 W</td>
			<td>yes</td>
		</tr>
		<tr>
			<td>ICP dilution gas (argon)</td>
			<td>0.58 L/min</td>
			<td>Yes</td>
		</tr>
		<tr>
			<td>Sampling depth</td>
			<td>8 mm</td>
			<td>Yes</td>
		</tr>
		<tr>
			<td>Collision gas</td>
			<td>2 mL/min</td>
			<td>Yes (for the same set of measurements don&#8217;t change this value after tuning it)&#160;&#160;</td>
		</tr>
		<tr>
			<td>Integration time&#160;</td>
			<td>0.2 s per isotope</td>
			<td>Yes, if the ICP time resolution should be changed&#160;</td>
		</tr>
		<tr>
			<td>Xe flow</td>
			<td>4 mL/min</td>
			<td>No (to keep the same ICP sensitivity)</td>
		</tr>
	</tbody>
</table>
Table 1: Typical Setting of the Main ICPMS Parameters used for the RDD-SMPS-ICPMS Measurement of Aerosol Particles.

Watch this Scientific Journal Video about A Practical Guide on Coupling a Scanning Mobility Sizer and Inductively Coupled Plasma Mass Spectrometer SMPS-ICPMS at JoVE.com

A Practical Guide on Coupling a Scanning Mobility Sizer and Inductively Coupled Plasma Mass Spectrometer SMPS-ICPMS

In this work a practical guide is provided, describing the different steps to establish the coupling of SMPS and ICPMS systems, and how to use them. Three descriptive examples are presented.

A Practical Guide on Coupling a Scanning Mobility Sizer and Inductively Coupled Plasma Mass Spectrometer (SMPS-ICPMS)

A large variety of analytical methods are available to characterize particles in aerosols and suspensions. The choice of the appropriate technique depends ...

a-practical-guide-on-coupling-scanning-mobility-sizer-inductively

Research

JoVE Journal

Chemistry

10.7K Views.  Paul Scherrer Institute.  In dit werk wordt een praktische handleiding verstrekt waarin de verschillende stappen beschreven worden om de koppeling van SMPS en ICPMS systemen te bepalen en hoe ze te gebruiken. Drie beschrijvende voorbeelden worden voorgesteld. 

Video: A Practical Guide on Coupling a Scanning Mobility Sizer and Inductively Coupled Plasma Mass Spectrometer SMPS-ICPMS

Standards for Quantitative Metalloproteomic Analysis Using Size Exclusion ICP-MS

Metals are essential for protein function as cofactors to catalyze chemical reactions. Disruption of metal homeostasis is implicated in a number of diseases including Alzheimer's and Parkinson's disease, but the exact role these metals play is yet to be fully elucidated. Identification of metalloproteins encounters many challenges and difficulties. Here we report an approach that allows metalloproteins in complex samples to be quantified. This is achieved using size exclusion chromatography coupled with inductively coupled plasma - mass spectrometry (SEC-ICP-MS). Using six known metalloproteins, the size exclusion column can be calibrated and the respective trace elements (iron, copper, zinc, cobalt, iodine) can be used for quantification. SEC-ICP-MS traces of human brain and plasma are presented. The use of these metalloprotein standards provides the means to quantitatively compare metalloprotein abundances between biological samples. This technique is poised to help shed light on the role of metalloproteins in neurodegenerative disease as well as other diseases where imbalances in trace elements are implicated.

Size exclusion chromatography hyphenated with inductively coupled plasma - mass spectrometry (ICP-MS) is a powerful tool to measure changes in the abundance of metalloproteins directly from biological samples. Here we describe a set of metalloprotein standards used to estimate molecular mass and the amount of metal associated with unknown proteins.

Metals are essential for protein function as cofactors to catalyze chemical reactions. Disruption of metal homeostasis is implicated in a number of ...

Quantitative and Qualitative Method for Sphingomyelin by LC-MS Using Two Stable Isotopically Labeled Sphingomyelin Species

We present a method of analyzing sphingomyelin (SM) qualitatively and quantitatively by liquid chromatography-electrospray Ionization-tandem mass spectrometry (LC-ESI-MS/MS). SM is a common sphingolipid composed of a phosphorylcholine and a ceramide as the hydrophilic and hydrophobic component, respectively. A number of SM species are present in mammalian cells due to a variety in the sphingoid long chain base (LCB) and an N-acyl moiety in the ceramide. In this report, we show a method of estimating the number of carbon and double bonds in a LCB and an N-acyl moiety based on their corresponding product ions in MS/MS/MS (MS3) experiments. In addition, we present a quantitative analysis method for SM using two stable isotopically labeled SM species, which facilitates determining the range used in SM quantitation. The present method will be useful in characterizing a variety of SM species in biological samples and industrial products such as cosmetics.

Here, we present a protocol to quantify and qualify each sphingomyelin species using multiple reaction monitoring and MS/MS/MS mode, respectively.

We present a method of analyzing sphingomyelin (SM) qualitatively and quantitatively by liquid chromatography-electrospray Ionization-tandem mass ...

Biochemistry

Sample Preparation for Probe Electrospray Ionization Mass Spectrometry

Mass spectrometry (MS) is a powerful tool in analytical chemistry because it provides very accurate information about molecules, such as mass-to-charge ratios (m/z), which are useful to deduce molecular weights and structures. While it is essentially a destructive analytical method, recent advancements in the ambient ionization technique have enabled us to acquire data while leaving tissue in a relatively intact state in terms of integrity. Probe electrospray ionization (PESI) is a so-called direct method because it does not require complex and time-consuming pretreatment of samples. A fine needle serves as a sample picker, as well as an ionization emitter. Based on the very sharp and fine property of the probe tip, destruction of the samples is minimal, allowing us to acquire the real-time molecular information from living things in situ. Herein, we introduce three applications of PESI-MS technique that will be useful for biomedical research and development. One involves the application to solid tissue, which is the basic application of this technique for the medical diagnosis. As this technique requires only 10 mg of the sample, it may be very useful in the routine clinical settings. The second application is for in vitro medical diagnostics where human blood serum is measured. The ability to measure fluid samples is also valuable in various biological experiments where a sufficient volume of sample for conventional analytical techniques cannot be provided. The third application leans toward the direct application of probe needles in living animals, where we can obtain real-time dynamics of metabolites or drugs in specific organs. In each application, we can infer the molecules that have been detected by MS or use artificial intelligence to obtain a medical diagnosis.

This article introduces sample preparation methods for a unique real-time analytical method based on the ambient mass spectrometry. This method lets us perform real-time analysis of the biological molecules in vivo without any special pretreatments.

Mass spectrometry (MS) is a powerful tool in analytical chemistry because it provides very accurate information about molecules, such as mass-to-charge ...

Versatile Dual-Inlet Sample Introduction System for Multi-Mode Single Particle Inductively Coupled Plasma Mass Spectrometry Analysis and Validation

Metal-containing nanoparticles (NP) can be characterized with inductively coupled plasma mass spectrometers (ICP-MS) in terms of their size and number concentration by using the single-particle mode of the instrument (spICP-MS). The accuracy of measurement depends on the setup, operational conditions of the instrument and specific parameters that are set by the user. The transport efficiency of the ICP-MS is crucial for the quantification of the NP and usually requires a reference material with homogenous size distribution and a known particle number concentration.
Currently, NP reference materials are available for only a few metals and in limited sizes. If particles are characterized without a reference standard, the results of both size and particle number may be biased. Therefore, a dual-inlet setup for characterizing nanoparticles with spICP-MS was developed to overcome this problem. This setup is based on a conventional introduction system consisting of a pneumatic nebulizer (PN) for nanoparticle solutions and a microdroplet generator (&#181;DG) for ionic calibration solutions. A new and flexible interface was developed to facilitate the coupling of &#181;DG, PN and the ICP-MS system. The interface consists of available laboratory components and allows for the calibration, nanoparticle (NP) characterization and cleaning of the arrangement, while the ICP-MS instrument is still running.
Three independent analysis modes are available for determining particle size and number concentration. Each mode is based on a different calibration principle. While mode I (counting) and mode III (&#181;DG) are known from the literature, mode II (sensitivity), is used to determine the transport efficiency by inorganic ionic standard solutions only. It is independent of NP reference materials. The &#181;DG based inlet system described here guarantees superior analyte sensitivities and, therefore, lower detection limits (LOD). The size dependent LODs achieved are less than 15 nm for all NP (Au, Ag, CeO2) investigated.

Here we provide a protocol for the use of a dual-inlet system for single particle inductively coupled mass spectrometry which allows for a standard independent nanoparticle characterization.

Metal-containing nanoparticles (NP) can be characterized with inductively coupled plasma mass spectrometers (ICP-MS) in terms of their size and number ...

Using a Cyclic Ion Mobility Spectrometer for Tandem Ion Mobility Experiments

Accurate characterization of chemical structures is important to understand their underlying biological mechanisms and functional properties. Mass spectrometry (MS) is a popular tool but is not always sufficient to completely unveil all structural features. For example, although carbohydrates are biologically relevant, their characterization is complicated by numerous levels of isomerism. Ion mobility spectrometry (IMS) is an interesting complement because it is sensitive to ion conformations and, thus, to isomerism. 
Furthermore, recent advances have significantly improved the technique: the last generation of Cyclic IMS instruments offers additional capabilities compared to linear IMS instruments, such as an increased resolving power or the possibility to perform tandem ion mobility (IMS/IMS) experiments. During IMS/IMS, an ion is selected based on its ion mobility, fragmented, and reanalyzed to obtain ion mobility information about its fragments. Recent work showed that the mobility profiles of the fragments contained in such IMS/IMS data can act as a fingerprint of a particular glycan and can be used in a molecular networking strategy to organize glycomics datasets in a structurally relevant way. 
The goal of this protocol is thus to describe how to generate IMS/IMS data, from sample preparation to the final Collision Cross Section (CCS) calibration of the ion mobility dimension that yields reproducible spectra. Taking the example of one representative glycan, this protocol will show how to build an IMS/IMS control sequence on a Cyclic IMS instrument, how to account for this control sequence to translate IMS arrival time into drift time (i.e., the effective separation time applied to the ions), and how to extract the relevant mobility information from the raw data. This protocol is designed to clearly explain the critical points of an IMS/IMS experiment and thus help new Cyclic IMS users perform straightforward and reproducible acquisitions.

Ion mobility spectrometry (IMS) is an interesting complement to mass spectrometry for the characterization of biomolecules, notably because it is sensitive to isomerism. This protocol describes a tandem IMS (IMS/IMS) experiment, which allows the isolation of a molecule and the generation of the mobility profiles of its fragments.

Accurate characterization of chemical structures is important to understand their underlying biological mechanisms and functional properties. Mass ...

Dose Uptake of Platinum- and Ruthenium-based Compound Exposure in Zebrafish by Inductively Coupled Plasma Mass Spectrometry with Broader Applications

Metals and metal-based compounds comprise multifarious pharmaco-active and toxicological xenobiotics. From heavy metal toxicity to chemotherapeutics, the toxicokinetics of these compounds have both historical and modern-day relevance. Zebrafish have become an attractive model organism in elucidating pharmaco- and toxicokinetics in environmental exposure and clinical translation studies. Although zebrafish studies have the benefit of being higher-throughput than rodent models, there are several significant constraints to the model.
One such limitation is inherent in the waterborne dosing regimen. Water concentrations from these studies cannot be extrapolated to provide reliable internal dosages. Direct measurements of the metal-based compounds allow for a better correlation with compound-related molecular and biological responses. To overcome this limitation for metals and metal-based compounds, a technique was developed to digest zebrafish larval tissue after exposure and quantify metal concentrations within tissue samples by inductively coupled plasma mass spectrometry (ICPMS).
ICPMS methods were used to determine the metal concentrations of platinum (Pt) from cisplatin and ruthenium (Ru) from several novel Ru-based chemotherapeutics in zebrafish tissue. Additionally, this protocol distinguished concentrations of Pt that were sequestered in the chorion of the larval compared with the zebrafish tissue. These results indicate that this method can be applied to quantitate the metal dose present in larval tissues. Further, this method may be adjusted to identify specific metals or metal-based compounds in a broad range of exposure and dosing studies.

The increased rate of pharmaco- and toxicokinetic analyses of metals and metal-based compounds in zebrafish can be advantageous for environmental and clinical translation studies. The limitation of unknown waterborne exposure uptake was overcome by conducting trace metal analysis on digested zebrafish tissue using inductively coupled plasma mass spectrometry.

Metals and metal-based compounds comprise multifarious pharmaco-active and toxicological xenobiotics. From heavy metal toxicity to chemotherapeutics, the ...

A Detailed Guide for Preparing Hard Palm Seeds for MALDI-IMS Analysis

Preparation of Hard Palm Seeds for Matrix-Assisted Laser Desorption/Ionization-Imaging Mass Spectrometry Analysis

Matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) is applied to identify compounds in their native environments. Currently, MALDI-IMS is frequently used in clinical analysis. Still, an excellent perspective exists for better applying this technique to understand chemical compounds&#39; physiological information in plant tissues. However, preparation may be challenging for specific samples from botanical materials, as MALDI-IMS requires thin slices (12-20 &#181;m) for appropriate data acquisition and successful analysis. In this sense, previously, we developed a sample preparation protocol to obtain thin sections of Euterpe oleracea (a&#231;a&#237; palm) hard seeds, enabling their molecular mapping by MALDI-IMS.
Here, we show that the developed protocol is suitable for preparing other seeds from the same genus. Briefly, the protocol was based on submerging the seeds in deionized water for 24 h, embedding samples with gelatin, and sectioning them in an acclimatized cryostat. Then, for matrix deposition, an xy motion platform was coupled to an electrospray ionization&#160;(ESI) needle spray using a 1:1 (v/v) 2,5-dihydroxybenzoic acid (DHB) and methanol solution with 0.1% trifluoroacetic acid at 30 mg/mL. E. precatoria and E. edulis seed data were processed using software to map their metabolite patterns.
Hexose oligomers were mapped within sample slices to prove the adequacy of the protocol for those samples, as it is known that those seeds contain large amounts of mannan, a polymer of the hexose mannose. As a result, peaks of hexose oligomers, represented by [M + K]+ adducts of (&#916; = 162 Da), were identified. Thus, the sample preparation protocol, previously developed tailor-made for E. oleracea seeds, also enabled MALDI-IMS analysis of two other hard palm seeds. In short, the method could constitute a valuable tool for research in the morpho-anatomy and physiology of botanical materials, especially from cut-resistant samples.

Author Spotlight: A Tailor-Made Sample Preparation Approach for Enhanced MALDI-IMS Analysis of Hard Palm Seeds

This protocol aimed to describe detailed guidance on the preparation of hard seed sample sections with low water content for MALDI-IMS analysis, maintaining analytes' original distribution and abundance and providing high-quality signal and spatial resolution.

Matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) is applied to identify compounds in their native environments. ...

Enhanced Isomeric Separation of Ergot Alkaloids Using LC-IMS-MS

Detection of Regulated Ergot Alkaloids in Food Matrices by Liquid Chromatography-Trapped Ion Mobility Spectrometry-Time-of-Flight Mass Spectrometry

Ion mobility mass spectrometry (IMS) acts as an additional separation dimension when integrated into liquid chromatography-mass spectrometry (LC-MS) workflows. LC-IMS-MS methods provide higher peak resolution, enhanced separation of isobaric and isomeric compounds, and improved signal-to-noise ratio (S/N) compared to traditional LC-MS methods. IMS provides another molecular characteristic for the identification of analytes, namely the collision cross section (CCS) parameter, reducing false positive results. Therefore, LC-IMS-MS methods address important analytical challenges in the field of food safety (i.e., detection of compounds at trace levels in complex food matrices and unambiguous identification of isobaric and isomeric molecules).
Ergot alkaloids (EAs) are a family of mycotoxins produced by fungi that attack a wide variety of grass species, including small grains such as rye, triticale, wheat, barley, millet, and oats. Maximum levels (MLs) of these mycotoxins have been established in several foodstuffs, as detailed in the Commission Regulation EC/2023/915. This new legislation includes six main EAs and their corresponding epimers, so an efficient methodology is required to properly distinguish these isomeric molecules considering their co-occurrence.
Therefore, the goal of this protocol is to show how the integration of IMS in LC-MS workflows contributes to the separation of isomeric EAs, enhancing the selectivity of the analytical method. Additionally, it illustrates how the generation of CCS libraries through the characterization of analytical standards provides higher confidence for the identification of mycotoxins. This protocol is designed to clearly explain the benefits of implementing IMS in food safety, taking as an example the determination of EAs in cereals. A QuEChERS-based extraction followed by an LC-trapped ion mobility spectrometry (TIMS)-MS analysis provided limits of quantification ranging from 0.65 to 2.6 ng/g with acceptable accuracy (although low recovery for ergotaminine) at 1.5x, 1x, and 0.5x the ML and exhibited a negligible matrix effect.

This protocol presents a validated liquid chromatography-ion mobility-high resolution mass spectrometry method to determine the presence of ergot alkaloids in food in compliance with the recently released Commission Regulation (EU) 2023/915.

Ion mobility mass spectrometry (IMS) acts as an additional separation dimension when integrated into liquid chromatography-mass spectrometry (LC-MS) ...

Applications of the Single-probe: Mass Spectrometry Imaging and Single Cell Analysis under Ambient Conditions

Mass spectrometry imaging (MSI) and in-situ single cell mass spectrometry (SCMS) analysis under ambient conditions are two emerging fields with great potential for the detailed mass spectrometry (MS) analysis of biomolecules from biological samples. The single-probe, a miniaturized device with integrated sampling and ionization capabilities, is capable of performing both ambient MSI and in-situ SCMS analysis. For ambient MSI, the single-probe uses surface micro-extraction to continually conduct MS analysis of the sample, and this technique allows the creation of MS images with high spatial resolution (8.5 &#181;m) from biological samples such as mouse brain and kidney sections. Ambient MSI has the advantage that little to no sample preparation is needed before the analysis, which reduces the amount of potential artifacts present in data acquisition and allows a more representative analysis of the sample to be acquired. For in-situ SCMS, the single-probe tip can be directly inserted into live eukaryotic cells such as HeLa cells, due to the small sampling tip size (&lt; 10 &#181;m), and this technique is capable of detecting a wide range of metabolites inside individual cells at near real-time. SCMS enables a greater sensitivity and accuracy of chemical information to be acquired at the single cell level, which could improve our understanding of biological processes at a more fundamental level than previously possible. The single-probe device can be potentially coupled with a variety of mass spectrometers for broad ranges of MSI and SCMS studies.

Here, we present protocols to perform both ambient mass spectrometry imaging (MSI) of tissues and in-situ live single cell MS (SCMS) analysis using the single-probe, which is a miniaturized multifunctional device for MS analysis.

Mass spectrometry imaging (MSI) and in-situ single cell mass spectrometry (SCMS) analysis under ambient conditions are two emerging fields with great ...

Biology

Introduction to Mass Spectrometry

Source: Laboratory of Dr. Khuloud Al-Jamal - King&#39;s College London

Mass spectrometry is an analytical chemistry technique that enables the identification of unknown compounds within a sample, the quantification of known materials, the determination of the structure, and chemical properties of different molecules.
A mass spectrometer is composed of an ionization source, an analyzer,&#160;and a detector. The process involves the ionization of chemical compounds to generate ions. When using inductively coupled plasma (ICP), samples containing elements of interest are introduced into argon plasma as aerosol droplets. The plasma dries the aerosol, dissociates the molecules, and then removes an electron from the components to be detected by the mass spectrometer. Other ionization methods such as electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) are used to analyze biological samples. Following the ionization procedure, ions are separated in the mass spectrometer according to their mass-to-charge ratio (m/z), and the relative abundance of each ion type is measured. Finally, the detector commonly consists in an electron multiplier where the collision of ions with a charged anode leads to a cascade of increasing number of electrons, which can be detected by an electrical circuit connected to a computer.
In this video, the procedure of ICP-MS analysis will be described by the detection of 56Fe as an example.

A Practical Guide on Coupling a Scanning Mobility Sizer and Inductively Coupled Plasma Mass Spectrometer (SMPS-ICPMS)

Samenvatting

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