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 ...

jinan university

Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution

Although traditional analytical techniques like gas chromatography (GC) and GC/mass spectrometry (MS) offer satisfactory sensitivity and good reproducibility for the detection of phthalic acid esters (PAEs) in a variety of matrices, they involve laborious sample pretreatment, are time-consuming, and some are expensive and environmentally unfriendly. Furthermore, there are thousands of spirits on the market; therefore, rapid and high-throughout methods suitable for the consistent detection and quantification of PAEs in spirits are urgently required.

Development of an air-flow-assisted extractive electrospray ionization source for rapid analysis of phthalic acid esters in spirits.

Using a single particle aerosol mass spectrometer (SPAMS), the chemical composition and size distributions of lead (Pb)-containing particles with diameter from 0.1 μm to 2.0 μm in Beijing were analyzed in the spring of 2011 during clear, hazy, and dusty days. Based on mass spectral features of particles, cluster analysis was applied to Pb-containing particles, and six major classes were acquired consisting of K-rich, carboneous, Fe-rich, dust, Pb-rich, and Cl-rich particles. Pb-containing particles accounted for 4.2-5.3%, 21.8-22.7%, and 3.2% of total particle number during clear, hazy and dusty days, respectively. K-rich particles are a major contribution to Pb-containing particles, varying from 30.8% to 82.1% of total number of Pb-containing particles, lowest during dusty days and highest during hazy days. The results reflect that the chemical composition and amount of Pb-containing particles has been affected by meteorological conditions as well as the emissions of natural and anthropogenic sources. K-rich particles and carbonaceous particles could be mainly assigned to the emissions of coal combustion. Other classes of Pb-containing particles may be associated with metallurgical processes, coal combustion, dust, and waste incineration etc. In addition, Pb-containing particles during dusty days were first time studied by SPAMS. This method could provide a powerful tool for monitoring and controlling of Pb pollution in real time.

Real time analysis of lead-containing atmospheric particles in Beijing during springtime by single particle aerosol mass spectrometry.

The eutrophication of surface water sources and climate changes have resulted in an annual explosion of cyanobacterial blooms in many irrigating and drinking water resources. To decrease health risks to the public, a rapid real time method for the synchronous determination of two usually harmful microcystins (MC-RR and MC-LR) in environmental water samples was built by employing a paper spray ionization method coupled with a time-of-flight mass spectrometer system. With this approach, direct analysis of microcystin mixtures without sample preparation has been achieved. Rapid detection was performed, simulating the release process of microcystins in reservoir water samples, and the routine detection frequency was every three minutes. The identification time of microcystins was reduced from several hours to a few minutes. The limit of detection is 1 μg/L, and the limit of quantitation is 3 μg/L. This method displays the ability for carrying out rapid, direct, and high-throughput experiments for determination of microcystins, and it would be of significant interest for environmental and food safety applications.

Rapid Microcystin Determination Using a Paper Spray Ionization Method with a Time-of-Flight Mass Spectrometry System.

Resonance ejection mass scan using dipole excitation with a non-integer frequency ratio in a digital linear ion trap mass spectrometer.

Direct mass spectrometry (MS)-based methods make it possible to monitor the molecular compositions of hundreds of volatile organic compounds (VOCs) in exhaled human breath in real time. Mass resolution and mass accuracy play important roles for direct MS analysis, especially for the low-concentration isobaric compounds in non-target research.

Direct human breath analysis by secondary nano-electrospray ionization ultrahigh-resolution mass spectrometry: Importance of high mass resolution and mass accuracy.

Cooking is an important source of volatile organic compounds (VOCs) and a potential source of secondary organic aerosol (SOA) both indoors and outdoors. In this study, VOC emissions from heating corn oil and stir-frying spices (i.e. garlic, ginger, myrcia and zanthoxylum piperitum (Sichuan pepper)) were characterized using an on-line membrane inlet vacuum ultraviolet single-photon ionization time-of-flight mass spectrometer (VUV-SPI-TOFMS). VOC emissions from heating corn oil were dominated by aldehydes, which were enhanced by factors of one order of magnitude when stir-frying spices. Stir-frying any of the spices studied generated large amounts of methylpyrrole (m/z 81). In addition, stir-frying garlic produced abundant dihydrohydroxymaltol (m/z 144) and diallyldisulfide (DADS) (m/z 146), while stir-frying ginger, myrcia and zanthoxylum piperitum produced abundant monoterpenes (m/z 136) and terpenoids (m/z 152, 154). SOA formed from emissions of stir-frying spices through reactions with excess ozone in a flow reactor as well as primary organic aerosol (POA) emissions were characterized using a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS). Stir-frying garlic and ginger generated similar POA concentrations to those from heating corn oil while stir-frying myrcia and zanthoxylum piperitum generated double the amount of emissions. No SOA was observed from stir-frying garlic and ginger. The rates of SOA production from stir-frying myrcia and zanthoxylum piperitum were 1.8μgmingand 8.7μgming, equivalent to 13.4% and 53.1% of their own POA emission rates, respectively. Therefore, the contribution of stir-frying spices to ambient organic aerosol levels is likely dominated by POA. The rates of total terpene emission from stir-frying myrcia and zanthoxylum piperitum were estimated to be 5.1μgmingand 24.9μgming, respectively. Our results suggest that stir-frying spices could be an important source of terpenes in indoor environments in Hong Kong, at least during cooking.

Emission of volatile organic compounds and production of secondary organic aerosol from stir-frying spices.

Benzene, well known as a ubiquitous environmental pollutant, can lead to increasing risk of cancer, bone marrow failure as well as other serious diseases. Benzene has been classified as carcinogenic to humans with no recommended safe level of exposure. In this study, the influence of time-of-day on benzene metabolism has been tentatively explored in a mouse model based on direct real-time breath analysis by using membrane inlet single photon ionization time of flight mass spectrometry (MI-SPI-TOFMS). The exhaled breath of eight mice was monitored at a time resolution of less than 20 s after intraperitoneal (I.P.) injection of benzene in the morning, afternoon and evening on different days, and two rounds of experiments were carried out in total. The pharmacokinetic parameters such as total exposure AUC(h ng/mL), peak level C(ng/mL), time of peak level t(h), and terminal half-life t(h) were calculated and discussed. The values of individual parameter varied greatly among the eight mice, e.g., AUCin the morning of the first round of experiment ranged from 10.66 to 162.17 h ng/mL and the mean ± SD was 103.72 ± 99.72 h ng/mL (n = 8). Significant difference has also been observed between two rounds of experiments, implying the damage in the liver caused by the benzene exposure. However, there is no significant difference among the results from the morning, afternoon and evening for each round of the experiment. In our follow-up study, the influence of time-of-day will be further investigated, in which the metabolites of benzene as well as endogenous metabolites will be considered.

Investigation on the influence of time-of-day on benzene metabolic pharmacokinetics by direct breath analysis in mice.

Non-thermal plasma (NTP) has proven to be an effective approach for the removal of volatile organic compounds (VOCs). However, harmful organic by-products, produced during NTP-mediated removal of VOCs, hinder practical applications of this technology. It is necessary to characterize the organic by-products to assess their health risks.

Quantification and risk assessment of organic products resulting from non-thermal plasma removal of toluene in nitrogen.

The study of ion chemistry involving the NOis currently the focus of considerable fundamental interest and is relevant in diverse fields ranging from mechanistic organic chemistry to atmospheric chemistry. A very intense source of NOwas generated by injecting the products from the dielectric barrier discharge of a nitrogen and oxygen mixture upstream into the drift tube of a proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) apparatus with HOas the reagent ion. The NOintensity is controllable and related to the dielectric barrier discharge operation conditions and ratio of oxygen to nitrogen. The purity of NOcan reach more than 99% after optimization. Using NOas the chemical reagent ion, the gas-phase reactions of NOwith 11 aromatic compounds were studied by PTR-TOF-MS. The reaction rate coefficients for these reactions were measured, and the product ions and their formation mechanisms were analyzed. All the samples reacted with NOrapidly with reaction rate coefficients being close to the corresponding capture ones. In addition to electron transfer producing [M], oxygen ion transfer forming [MO], and 3-body association forming [M·NO], a new product ion [M-C]was also formed owing to the loss of C═O from [MO].This work not only developed a new chemical reagent ion NObased on PTR-MS but also provided significant interesting fundamental data on reactions involving aromatic compounds, which will probably broaden the applications of PTR-MS to measure these compounds in the atmosphere in real time.

Zhen Zhou

Institute of Mass Spectrometer and Atmospheric Environment

jinan university

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

Zhen Zhou

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Institute of Mass Spectrometer and Atmospheric Environment

jinan university

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

Institute of Mass Spectrometer and Atmospheric Environment