Name: real-time breath analysis by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry
Uploaded: 2018-03-09T12:30:00
Description: Watch this Scientific Journal Video about Real-time Breath Analysis by Using Secondary Nanoelectrospray Ionization Coupled to High Resolution Mass Spectrometry at JoVE.com

This work has been financially supported by National Natural Science Foundation of China (No. 91543117).

Caution: Please consult all relevant material safety data sheets (MSDS) before use. Please use appropriate personal protective equipment, e.g., lab coat, gloves, goggles, full length pants and closed-toe shoes).
1. Set up the Sec-nanoESI source
<ol>
	<li>Set up a Sec-nanoESI source according to the SESI process, i.e., the breath gas is introduced to intersect an electrospray plume and ionized by the charged droplets (Figure 1). The sources buil...

<ol>
	<li>De Lacy Costello, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+the+volatiles+from+the+healthy+human+body.">A review of the volatiles from the healthy human body.</a> J. Breath Res. 8 (1), 014001-014030 (2014).</li><li>Phillips, M., Greenberg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ion-trap+detection+of+volatile+organic+compounds+in+alveolar+breath.">Ion-trap detection of volatile organic compounds in alveolar breath.</a> Clin. Chem. 38 (1), 60-65 (1992).</li><li>Mart&#237;nez-Lozano Sinues, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circadian+variation+of+the+human+metabolome+captured+by+real-time+breath+analysis.">Circadian variation of the human metabolome captured by real-time breath analysis.</a> PLoS One. 9 (12), 0114422-0114438 (2014).</li><li>Garcia-Gomez, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Secondary+electrospray+ionization+coupled+to+high-resolution+mass+spectrometry+reveals+tryptophan+pathway+metabolites+in+exhaled+human+breath.">Secondary electrospray ionization coupled to high-resolution mass spectrometry reveals tryptophan pathway metabolites in exhaled human breath.</a> Chem. Common. 52 (55), 8526-8528 (2016).</li><li>Garcia-Gomez, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+quantification+of+amino+acids+in+the+exhalome+by+secondary+electrospray+ionization-mass+spectrometry:+A+proof-of-principle+Study.">Real-time quantification of amino acids in the exhalome by secondary electrospray ionization-mass spectrometry: A proof-of-principle Study.</a> Clin. Chem. 62 (9), 1230-1237 (2016).</li><li>Mart&#237;nez-Lozano Sinues, P., Kohler, M., Brown, S. A., Zenobia, R., Dallmann, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gauging+circadian+variation+in+ketamine+metabolism+by+real-time+breath+analysis.">Gauging circadian variation in ketamine metabolism by real-time breath analysis.</a> Chem. Common. 53 (14), 2264-2267 (2017).</li><li>Gamez, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time,+in+vivo+monitoring+and+pharmacokinetics+of+valproic+acid+via+a+novel+biomarker+in+exhaled+breath.">Real-time, in vivo monitoring and pharmacokinetics of valproic acid via a novel biomarker in exhaled breath.</a> Chem. Common. 47 (17), 4884-4886 (2011).</li><li>Li, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+pharmacokinetics+determined+by+real-time+analysis+of+mouse+breath.">Drug pharmacokinetics determined by real-time analysis of mouse breath.</a> Angew. Chem. Int. Ed. 54 (27), 7815-7818 (2015).</li><li>Amorim, L. L. A., Cardeal, Z. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breath+air+analysis+and+its+use+as+a+biomarker+in+biological+monitoring+of+occupational+and+environmental+exposure+to+chemical+agents.">Breath air analysis and its use as a biomarker in biological monitoring of occupational and environmental exposure to chemical agents.</a> J. Chromatogr. B. 853 (1-2), 1-9 (2007).</li><li>Bajtarevic, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+detection+of+lung+cancer+by+analysis+of+exhaled+breath.">Noninvasive detection of lung cancer by analysis of exhaled breath.</a> BMC Cancer. 9, 348 (2009).</li><li>Smith, D., Wang, T. S., Pysanenko, A., &#352;pan&#283;l, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+selected+ion+flow+tube+mass+spectrometry+study+of+ammonia+in+mouth-+and+nose-exhaled+breath+and+in+the+oral+cavity.">A selected ion flow tube mass spectrometry study of ammonia in mouth- and nose-exhaled breath and in the oral cavity.</a> Rapid Commun. Mass Spectrom. 22 (6), 783-789 (2008).</li><li>Li, X., Huang, L., Zhu, H., Zhou, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+human+breath+analysis+by+secondary+nano-electrospray+ionization+ultrahigh+resolution+mass+spectrometry:+Importance+of+high+mass+resolution+and+mass+accuracy.">Direct human breath analysis by secondary nano-electrospray ionization ultrahigh resolution mass spectrometry: Importance of high mass resolution and mass accuracy.</a> Rapid Commun. Mass Spectrom. 31 (3), 301-308 (2017).</li><li>Mart&#237;nez-Lozano, P., Fernandez de la Mora, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrospray+ionization+of+volatiles+in+breath.">Electrospray ionization of volatiles in breath.</a> Int. J. Mass Spectrom. 265 (1), 68-72 (2007).</li><li>Zeng, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+creatinine+in+exhaled+breath+of+humans+with+chronic+kidney+disease+by+extractive+electrospray+ionization+mass+spectrometry.">Detection of creatinine in exhaled breath of humans with chronic kidney disease by extractive electrospray ionization mass spectrometry.</a> J. Breath Res. 10 (1), 016008-016015 (2016).</li><li>Chen, H. W., Wortmann, A., Zhang, W. H., Zenobi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+in+vivo+fingerprinting+of+nonvolatile+compounds+in+breath+by+extractive+electrospray+ionization+quadrupole+time-of-flight+mass+spectrometry.">Rapid in vivo fingerprinting of nonvolatile compounds in breath by extractive electrospray ionization quadrupole time-of-flight mass spectrometry.</a> Angew. Chem. Int. Ed. 46 (4), 580-583 (2007).</li><li>Benoi, F. M., Davldson, W. R., Lovett, A. M., Nacson, S., Ngo, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breath+analysis+by+atmospheric+pressure+ionization+mass+spectrometry.">Breath analysis by atmospheric pressure ionization mass spectrometry.</a> Anal. Chem. 55 (4), 805-807 (1983).</li><li>Bregy, L., Mart&#237;nez-Lozano Sinues, P., Nudnova, M. M., Zenobi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+breath+analysis+with+active+capillary+plasma+ionization-ambient+mass+spectrometry.">Real-time breath analysis with active capillary plasma ionization-ambient mass spectrometry.</a> J. Breath Res. 8 (2), 027102-027110 (2014).</li><li>Gaugg, M. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expanding+metabolite+coverage+of+real-time+breath+analysis+by+coupling+a+universal+secondary+electrospray+ionization+source+and+high+resolution+mass+spectrometry-a+pilot+study+on+tobacco+smokers.">Expanding metabolite coverage of real-time breath analysis by coupling a universal secondary electrospray ionization source and high resolution mass spectrometry-a pilot study on tobacco smokers.</a> J. Breath Res. 10 (1), 016010-016020 (2016).</li><li>Mart&#237;nez-Lozano, P., Zingaro, L., Finiguerra, A., Cristoni, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Secondary+electrospray+ionization-mass+spectrometry:+breath+study+on+a+control+group.">Secondary electrospray ionization-mass spectrometry: breath study on a control group.</a> J. Breath Res. 5 (1), 016002-016012 (2011).</li><li>Mart&#237;nez-Lozano Sinues, P., Zenobi, R., Kohler, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+exhalome+a+diagnostic+tool+of+the+future.">Analysis of the exhalome a diagnostic tool of the future.</a> Chest. 144 (3), 746-749 (2013).</li><li>Mart&#237;nez-Lozano Sinues, P., Fernandez de la Mora, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+analysis+of+fatty+acid+vapors+in+breath+by+electrospray+ionization+and+atmospheric+pressure+Ionization-Mass+Spectrometry.">Direct analysis of fatty acid vapors in breath by electrospray ionization and atmospheric pressure Ionization-Mass Spectrometry.</a> Anal. Chem. 80 (21), 8210-8215 (2008).</li><li>Mart&#237;nez-Lozano Sinues, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breath+analysis+in+real+time+by+mass+spectrometry+in+chronic+obstructive+pulmonary+disease.">Breath analysis in real time by mass spectrometry in chronic obstructive pulmonary disease.</a> Respiration. 87 (4), 301-310 (2014).</li><li>Mart&#237;nez-Lozano Sinues, P., Kohler, M., Zenobi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+diurnal+changes+in+exhaled+human+breath.">Monitoring diurnal changes in exhaled human breath.</a> Anal. Chem. 85 (1), 369-373 (2013).</li><li>Chen, H. W., Zenobi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neutral+desorption+sampling+of+biological+surfaces+for+rapid+chemical+characterization+by+extractive+electropray+ionization+mass+spectrometry.">Neutral desorption sampling of biological surfaces for rapid chemical characterization by extractive electropray ionization mass spectrometry.</a> Nat. Protoc. 3 (9), 1467-1475 (2008).</li><li>Li, X., Hu, B., Ding, J., Chen, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+characterization+of+complex+viscous+samples+at+molecular+levels+by+neutral+desorption+extractive+electrospray+ionization+mass+spectrometry.">Rapid characterization of complex viscous samples at molecular levels by neutral desorption extractive electrospray ionization mass spectrometry.</a> Nat. Protoc. 7 (6), 1010-1025 (2011).</li><li>Gordon, S. M., Szidon, J. P., Krotoszynski, B. K., Gibbons, R. D., O'Neill, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Volatile+organic+compounds+in+exhaled+air+from+patients+with+lung+cancer.">Volatile organic compounds in exhaled air from patients with lung cancer.</a> Clin. Chem. 31 (8), 1278-1282 (1985).</li><li>Ding, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+extractive+electrospray+ionization+ion+trap+mass+spectrometry+in+vivo+breath+analysis.">Development of extractive electrospray ionization ion trap mass spectrometry in vivo breath analysis.</a> Analyst. 134 (10), 2040-2050 (2009).</li><li>Basum, G., Dahnke, H., Halmer, D., Hering, P., M&#252;rtz, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Online+recording+of+ethane+trances+in+human+breath+via+infrared+laser+spectroscopy.">Online recording of ethane trances in human breath via infrared laser spectroscopy.</a> J. Appl. Physiol. 95 (6), 2583-2590 (2003).</li><li>T&#248;ien, &. #. 2. 1. 6. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+open+flow+respirometry+in+continuous+and+long-term+measurements:+design+and+principles.">Automated open flow respirometry in continuous and long-term measurements: design and principles.</a> J. Appl. Physiol. 114 (8), 1094-1107 (2013).</li><li>Huang, L., Li, X., Xu, M., Huang, Z. X., Zhou, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+relatively+high+molecular+weight+compounds+in+human+breath+using+secondary+nano+electrospray+ionization+ultrahigh+resolution+mass+spectrometry.">Identification of relatively high molecular weight compounds in human breath using secondary nano electrospray ionization ultrahigh resolution mass spectrometry.</a> Chem. J. Chinese U. 38 (5), 752-757 (2017).</li></ol>

Constructing the Sec-nanoESI source based on a commercial nanoESI source, the ionization efficiency is higher than that of using an ESI source30. In addition, the ionization efficiency is further improved in a closed chamber, as it isolates the process from the ambient background air, and at the same time facilitates the mixing between the gas sample and the spray plume. By using a Sec-nanoESI, less parameters need to be optimized compared to an ESI source, making it easier for installation, appli...

With fast development of modern analytical techniques, hundreds of volatile organic compounds (VOCs) have been identified in human exhaled breath1. These VOCs mostly result from alveolar air (~350 mL for a healthy adult) and anatomical dead space air (~150 mL)2, which are affected by body metabolism3,4,5,6,7,8 and environmental pollution9, respectively. As a result, if identified, these VOCs are promising to be used as biomarkers for disease diagnosis and environmental exposure in a non-invasive manner.
Though gas chromatography mass spectrometry (GC-MS) is the most widely used technique for qualitative and quantitative analysis of exhaled VOCs2, direct MS techniques, which have been developed for real-time breath analysis, have the advantages of high time resolution and simple sample pre-preparation. Direct MS techniques, such as proton transfer reaction MS (PTR-MS)10, selected ion flow tube MS (SIFT-MS)11, secondary electrospray ionization MS (SESI-MS)12,13 (also named as extractive electrospray ionization MS, EESI-MS14,15), trace atmospheric gas analyzer (TAGA)16 and plasma ionization MS (PI-MS)17 have been investigated in recent years.
Among all the direct MS techniques, SESI is well-known as a universal soft ionization technique19,20,21; and the source is easy to be customized and coupled to different types of mass spectrometers, e.g., time of flight mass spectrometer8,15, ion trap mass spectrometer14 and orbitrap mass spectrometer12,18. Up to now, SESI-MS has been successfully used in diagnosing respiratory diseases22, gauging circadian rhythm3,6,23, pharmacokinetics7,8, and revealing metabolic pathways4, etc. Most recently, a commercial SESI source has become available.
In this study, a facile and compact secondary nanoelectrospray ionization source (Sec-nanoESI) was set up and coupled to a high-resolution mass spectrometer. Real-time measurements of exhaled VOCs in breath were presented.

<table>
	<tbody>
		<tr>
			<td>Ultrapure water</td>
			<td>Merck Millipore, USA</td>
			<td>MPGP04001</td>
			<td>Resistance &#62;18.2 M&#937;&#183;cm</td>
		</tr>
		<tr>
			<td>Formic acid</td>
			<td>Sigma-Aldrich, USA</td>
			<td>F0507</td>
			<td>Corrosive to the respiratory tract.</td>
		</tr>
		<tr>
			<td>Nitrogen gas</td>
			<td>Guangzhou Shiyuan Gas Co. Ltd., China</td>
			<td>N.A.a</td>
			<td>Purity &#62;99.99%</td>
		</tr>
		<tr>
			<td>Q Exactive hybrid quadrupole-orbitrap mass spectrometer</td>
			<td>Thermo Scientific, USA</td>
			<td>02634L(S/N)</td>
			<td>Beware of high voltage and high temperature</td>
		</tr>
		<tr>
			<td>NanoESI source</td>
			<td>Thermo Scientific, USA</td>
			<td>ES002373(S/N); ES071(P/N)</td>
			<td>Beware of high voltage and high temperature</td>
		</tr>
		<tr>
			<td>Nano LC pump</td>
			<td>Thermo Scientific, USA</td>
			<td>5041.0010A(P/N)</td>
			<td>/</td>
		</tr>
		<tr>
			<td>Xcalibur software (Version 3.0)</td>
			<td>Thermo Scientific, USA</td>
			<td>BRE0008596</td>
			<td>/</td>
		</tr>
		<tr>
			<td>Dino-Lite Digital Microscope</td>
			<td>Tech Video System (SuZhou) Co.Ltd., China</td>
			<td>CQ401833R(S/N)</td>
			<td>/</td>
		</tr>
		<tr>
			<td>Nafion tubing</td>
			<td>Perma Pure LLC, USA</td>
			<td>ME60</td>
			<td>/</td>
		</tr>
		<tr>
			<td>PTFE tubing (I.D. 4 mm)</td>
			<td>Dongguan Hongfu Insulating Material Co. Ltd., China</td>
			<td>N.A.</td>
			<td>Beware of the possible loss of polar compounds</td>
		</tr>
		<tr>
			<td>Mass flow controller</td>
			<td>Line-Tech, Korea</td>
			<td>M15122007 (S/N)</td>
			<td>/</td>
		</tr>
		<tr>
			<td>Flow meter</td>
			<td>Yuyao Industrial Automation Meter Factory, China</td>
			<td>40784</td>
			<td>/</td>
		</tr>
		<tr>
			<td>aN.A.: not available.</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

real-time breath analysis by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental exposure in a non-invasive manner. In this work, we present a protocol to characterize the exhaled VOCs in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry (Sec-nanoESI-HRMS). The homemade Sec-nanoESI source was readily set up based on a commercial nanoESI source. Hundreds of peaks were observed in the background-subtracted mass spectra of exhaled breath, and the mass accuracy values are -4.0-13.5 ppm and -20.3-1.3 ppm in the positive and negative ion detection modes, respectively. The peaks were assigned with accurate elemental composition according to the accurate mass and isotopic pattern. Less than 30 s is used for one exhalation measurement, and it takes approximately 7 min for six replicated measurements.

Figure 3 shows the breath fingerprints in the mass range of m/z 50-750 recorded under both positive and negative ion detection modes. 291 peaks (peak intensity &#62; 5.0x104) and 173 peaks (peak intensity &#62; 3.0x104) have been observed in background-subtracted breath fingerprints in the positive and negative ion detection modes, respectively. To identify peaks in the mass spectra, please refer to prior publications for detail...

Watch this Scientific Journal Video about Real-time Breath Analysis by Using Secondary Nanoelectrospray Ionization Coupled to High Resolution Mass Spectrometry at JoVE.com

Real-time Breath Analysis by Using Secondary Nanoelectrospray Ionization Coupled to High Resolution Mass Spectrometry

A protocol for characterizing chemical composition of exhaled breath in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry is demonstrated.

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental ...

The overall goal of this experiment is to characterize chemical composition of exhaled breath using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry. This method can help to answer key questions in the medical field such as early diagnosis of diseases, therapeutic check monitoring, and environmental exposure. The main advantage of the technique is the measurement can be performed in real time.The technique is also highest output, sensitive, specific, and user friendly. The implications of this technique have been extend to the diagnosis of lung cancer. Because chance of bio marker candidates have been find in exhaled breath of lung caner patients at different stages.Generally, individuals new to this method will struggle because the ionization source is commonly co-made. Visual demonstration is critical, as there is no standard protocol for this method yet. To begin, set up a secondary nano ESI source according to the secondary electrospary ionization process in which breath gas is introduced to intersect an electrospray plume and ionized by the charged droplets.The sources for the individual labs depend on the mass spectrometer used. Here, the secondary nano ESI source is based on the commercial nano ESI source. And attached it to a bench drop quarter pull orbit trap mass spectrometer.The main body of the source is a cubic stainless steel chamber with an inlet to introduce the nano ESI capillary into the chamber. Two stainless steel tubes are installed on each side of the chamber for gas delivery. Two quartz windows are equipped on the top and bottom of the chamber to check the position of the tip of the nano ESI capillary and nano ESI spray either by eyes or a digital microscope.Finally, the chamber is welded to the sweep cone of the mass spectrometer. Note that the design may change depending on the particular geometry of the atmospheric pressure interface of the mass spectrometer used in individual labs. Calibrate the mass spectrometer in both positive and negative ion detection modes according to manufacturers instructions.By applying calibration, mass spectrometer parameters, such as lens potentials and detection conditions are optimized to give good sensitivity and peak shape at a specified resolution value. Perform complete calibrations by using the commercial ESI source. The mass resolution of 70, 000 is used here.Mass calibration can be performed with any compatible sources, including customized ones. Set the temperature of the ion transfer tube of the mass spectrometer to greater than 100 degrees Celsius. Though the highest temperature can be set at 350 degrees Celsius, it may result in the decomposition of some compounds.For the ESI solvent and flow rate, select the appropriate ESI solvent on the basis of properties of solvent and targeted compounds. In this experiment use water containing 0.1%Formic Acid, for high ionization efficiency. Set the flow rate of the ESI solvent in the range of 0 1.5 microliters per minute, to 200 nanoliters per minute.Optimize the secondary nano ESI source parameters, mainly nano ESI voltage and nano ESI capillary tip position. The voltage commonly ranges from 2.0 4.5 kilovolts. Use 2.5 kilovolts here.Apply pure gas to the source to reduce the influence of volatile organic compounds or VOCs from indoor air. High purity nitrogen is used here and delivered at 0.8 liters per minute. With the presence of pure gas, the normalized intensity level observed in a mass spectrum should be greater than 1 x 10 to the 5th, and the variation of the TIC should be less than 10%in both positive and negative ion detection modes.When performing measurement, inhale the indoor air and perform a normal exhalation to breathe out all the air in the lungs at a constant flow rate. Monitor the exhalation flow rate either by a manometer or a flow meter visible to the subject. Connect the inlet of the flow meter to nafion tubing to remove the water vapor in the exhaled breath.Then, connect the outlet of the flow meter to PTFE tubing to deliver the breath gas. In this experiment, the subject exhaled at 0.4 liters per minute, as controlled by a flow meter. It takes less than 30 seconds for one exhalation measurement.Perform four to six replicated measurements. To minimize confounding effects, have participants abstain from eating, drinking, and brushing their teeth at least 30 minutes prior to the measurements. During the measurement, keep checking if the iron intensity exceeds the linear detection limit of the instrument or not.The saturation of signal can lead to an artifact peak that does not result from a compound in the sample. By inhaling through the nose, part of ambient VOCs and particles would be removed. However, it is noteworthy that compounds in the nasal passages may also be detected.Use software to record chromatagrams and mass spectra. Because this is direct MS analysis, and no chromatagraphic separation is performed, the TIC actually indicates the time trace of all the signals detected in the mass spectra. And the EIC shows a time trace of a specified compound.Shown here are representative results of exhaled breath measurements in real time. The time trace of endol, a typical endogenous compound, shows six replicated measurements in less than seven minutes. For all the measurements, reproducible background subtracted breath fingerprints were obtained in positive ion detection mode.291 compounds have been observed. The compounds are most likely aldehydes, ketones, and alkynes. In the case of breath fingerprints in negative ion detection mode, 173 compounds are presented, and mainly result from fatty acids.After watching this video, you should have a good understanding of how to set up a homemade CESI source and perform real time process analysis. Once mastered, the measurement can be performed in minutes. If it is performed properly.While attending this procedure, it is important to remember to avoid interference of the compounds from the sampling tubing and endo air. Know this measure can provide insights into human exhaled breath, and can also be applied to other systems such as model alkylize, ion models, and in retro-cell systems. Following this procedure, other measures like GCMS, HPRCMS, can be performed to answer additional questions, like for photo confirmation, quantity of analysis.After it's development, the technique paved the ways for researchers in the field of medicine to explore with this diagnosis, treatment effects in the patients.

Research

JoVE Journal

Chemistry

Untargeted Metabolomics from Biological Sources Using Ultraperformance Liquid Chromatography-High Resolution Mass Spectrometry (UPLC-HRMS)

Untargeted Metabolomics from Biological Sources Using Ultraperformance Liquid Chromatography-High Resolution Mass Spectrometry UPLC-HRMS

Here we present a workflow to analyze the metabolic profiles for biological samples of interest including; cells, serum, or tissue. The sample is first ...

A Study of the Complexation of Mercury(II) with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

A Study of the Complexation of MercuryII with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, ...

Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, ...

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry

Chemical analysis of volatile and semivolatile compounds dissolved in liquid samples can be challenging. The dissolved components need to be brought to ...

Synthesis and Mass Spectrometry Analysis of Oligo-peptoids

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have ...

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) Mass Spectrometry

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry

There are many techniques that can be employed in the characterization of synthetic homopolymers, but few provide as useful of information for end group ...

An Efficient Sample Preparation Method to Enhance Carbohydrate Ion Signals in Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

Sample preparation is a critical process in mass spectrometry (MS) analysis of carbohydrates. Although matrix-assisted laser desorption/ionization (MALDI) ...

High-throughput and Comprehensive Drug Surveillance Using Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug ...