scholarly journals Atmospheric sulphuric acid and neutral cluster measurements using CI-APi-TOF

2011 ◽  
Vol 11 (12) ◽  
pp. 31983-32002 ◽  
Author(s):  
T. Jokinen ◽  
M. Sipilä ◽  
H. Junninen ◽  
M. Ehn ◽  
G. Lönn ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
High Resolution Mass Spectrometry ◽  
Limit Of Detection ◽  
Neutral Cluster ◽  
Mass Spectrometers ◽  
Sensitive Tool ◽  
Charged Clusters ◽  
Ambient Measurements

Abstract. The first ambient measurements using nitrate ion based Chemical Ionization with the Atmospheric Pressure interface Time-Of-Flight mass spectrometer (CI-APi-TOF) for sulphuric acid and neutral cluster detection are presented. We have found CI-APi-TOF a highly stable and sensitive tool for molecular sulphuric acid detection. The lowest limit of detection for sulphuric acid was determined to be 3 × 104 molecules cm−3 for two hour averaging. Signals from sulphuric acid clusters up to tetramer accompanied by ammonia were also obtained but these were found to result from naturally charged clusters formed by ion induced clustering in the atmosphere during nucleation. Opposite to earlier studies with cluster mass spectrometers, we had no indication of neutral clusters. The reason is either less efficient charging of clusters in comparison to molecular sulphuric acid, or in low concentration of neutral clusters at our measurement site during these particular nucleation events. We show that utilizing high resolution mass spectrometry is crucial in separating the weak sulfuric acid cluster signal from the other compounds.

scholarly journals Atmospheric sulphuric acid and neutral cluster measurements using CI-APi-TOF

2012 ◽  
Vol 12 (9) ◽  
pp. 4117-4125 ◽  
Author(s):  
T. Jokinen ◽  
M. Sipilä ◽  
H. Junninen ◽  
M. Ehn ◽  
G. Lönn ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
High Resolution Mass Spectrometry ◽  
Limit Of Detection ◽  
Neutral Cluster ◽  
Mass Spectrometers ◽  
Sensitive Tool ◽  
Charged Clusters ◽  
Ambient Measurements

Abstract. The first ambient measurements using nitrate ion based Chemical Ionization with the Atmospheric Pressure interface Time-Of-Flight mass spectrometer (CI-APi-TOF) for sulphuric acid and neutral cluster detection are presented. We have found CI-APi-TOF a highly stable and sensitive tool for molecular sulphuric acid detection. The lowest limit of detection for sulphuric acid was determined to be 3.6 × 104 molecules cm−3 for 15 min averaging. Signals from sulphuric acid clusters up to tetramer containing ammonia were also obtained but these were found to result from naturally charged clusters formed by ion induced clustering in the atmosphere during nucleation. Opposite to earlier studies with cluster mass spectrometers, we had no indication of neutral clusters. The reason is either less efficient charging of clusters in comparison to molecular sulphuric acid, or the low concentration of neutral clusters at our measurement site during these particular nucleation events. We show that utilizing high resolution mass spectrometry is crucial in separating the weak sulfuric acid cluster signal from other compounds.

Newly developed instrumentation for measuring highly oxidized molecules at atmospheric pressure

2021 ◽  
Author(s):  
Paap Koemets ◽  
Sander Mirme ◽  
Kuno Kooser ◽  
Heikki Junninen
Keyword(s):  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Measurement Technology ◽  
Differential Mobility Analyzer ◽  
Neutral Cluster ◽  
Differential Mobility ◽  
Alpha Pinene ◽  
Ambient Measurements

<p>The Highly Oxidized Molecule Ion Spectrometer (HOMIS) is a novel instrument for measuring the total concentration of highly oxidized molecules (HOM-s) (Bianchi et al., 2019) at atmospheric pressure. The device combines a chemical ionization charger with a multi-channel differential mobility analyzer. The chemical ionization charger is based on the principles outlined by Eisele and Tanner (1993). The charger is attached to a parallel differential mobility analyzer identical to the ones used in the Neutral cluster and Air Ion Spectrometer (NAIS, Mirme 2011), but with modified sample and sheath air flow rates to improve the mobility resolution of the device. The complete mobility distribution in the range from 3.2 to 0.056 cm<sup>2</sup>/V/s is measured simultaneously by 25 electrometers. The range captures the charger ions, monomers, dimers, trimers but also extends far towards larger particles to possibly detect larger HOM-s that have not been measured with existing instrumentation. The maximum time resolution of the device is 1 second allowing it to detect rapid changes in the sample. The device has been designed to be easy to use, require little maintenance and work reliably in various environments during long term measurements.</p><p>First results of the prototype were acquired from laboratory experiments and ambient measurements. Experiments were conducted at the Laboratory of Environmental Physics, University of Tartu. The sample was drawn from a reaction chamber where alpha-pinene and ozone were introduced. Initial results show a good response when concentrations of alpha-pinene and ozone were changed. </p><p>Ambient measurements were conducted at the SMEAR Estonia measurement station in a hemiboreal forest for 10 days in the spring and two months in the winter of 2020. The HOMIS measurements were performed together with a CI-APi-TOF (Jokinen et al., 2012).</p><p> </p><p>References:</p><p>Bianchi, F., Kurtén, T., Riva, M., Mohr, C., Rissanen, M. P., Roldin, P., Berndt, T., Crounse, J. D., Wennberg, P. O., Mentel, T. F., Wildt, J., Junninen, H., Jokinen, T., Kulmala, M., Worsnop, D. R., Thornton, J. A., Donahue, N., Kjaergaard, H. G. and Ehn, M. (2019), “Highly Oxygenated Organic Molecules (HOM) from Gas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor to Atmospheric Aerosol”, Chemical Reviews, 119, 6, 3472–3509</p><p>Eisele, F. L., Tanner D. J. (1993), “Measurement of the gas phase concentration of H2SO4 and methane sulfonic acid and estimates of H2SO4 production and loss in the atmosphere”, JGR: Atmospheres, 98, 9001-9010</p><p>Jokinen T., Sipilä M., Junninen H., Ehn M., Lönn G., Hakala J., Petäjä T., Mauldin III R. L., Kulmala M., and Worsnop D. R. (2012), “Atmospheric sulphuric acid and neutral cluster measurements using CI-APi-TOF”, Atmospheric Chemistry and Physics, 12, 4117–4125</p><p>Mirme, S. (2011), “Development of nanometer aerosol measurement technology”, Doctoral thesis, University of Tartu</p>

scholarly journals Development and validation of sensitive method for determination of serum cotinine in smokers and nonsmokers by liquid chromatography/atmospheric pressure ionization tandem mass spectrometry

1997 ◽  
Vol 43 (12) ◽  
pp. 2281-2291 ◽  
Author(s):  
John T Bernert ◽  
Wayman E Turner ◽  
James L Pirkle ◽  
Connie S Sosnoff ◽  
James R Akins ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Atmospheric Pressure ◽  
High Resolution Mass Spectrometry ◽  
Limit Of Detection ◽  
Atmospheric Pressure Chemical Ionization ◽  
Current Method ◽  
Specific Method ◽  
Tandem Mass ◽  
Serum Samples ◽  
Serum Cotinine

Abstract We describe a sensitive and specific method for measuring cotinine in serum by HPLC coupled to an atmospheric pressure chemical ionization tandem mass spectrometer. This method can analyze 100 samples/day on a routine basis, and its limit of detection of 50 ng/L makes it applicable to the analysis of samples from nonsmokers potentially exposed to environmental tobacco smoke. Analytical accuracy has been demonstrated from the analysis of NIST cotinine standards and from comparative analyses by both the current method and gas chromatography/high-resolution mass spectrometry. Precision has been examined through the repetitive analysis of a series of bench and blind QC materials. This method has been applied to the analysis of cotinine in serum samples collected as part of the Third National Health and Nutrition Examination Survey (NHANES III).

scholarly journals Determination of homocysteine by lc-ms-ms with atmospheric pressure chemical ionization

2014 ◽  
Vol 60 (2) ◽  
pp. 235-245
Author(s):  
I.I. Miroshnichenko ◽  
A.I. Platova ◽  
T.P. Safarova ◽  
O.B. Yakovleva
Keyword(s):  
Human Blood ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Limit Of Detection ◽  
Atmospheric Pressure Chemical Ionization ◽  
Coefficient Of Determination ◽  
Ionization Mass ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical

Homocysteine (Hcy) is an intermediate of methionine metabolism. High plasma Hcy concentrations are an independent risk factor for stroke, peripheral vascular disease, deep venous thrombosis, coronary disease, and cognitive deficiency. Apparently, it is a great importance to measure Hcy levels in human blood. A new method for the quantification of Hcy by means of reversed-phase LC/atmospheric pressure chemical ionization mass spectrometry has been developed. The MRM ion transition, m/z 136.0 ® 90.0 was used for Hcy quantification. The limit of detection was 0.4 mM, quantification was performed from 1 mM to 40 mM with coefficient of determination of R2=0,997. The method was applied successfully to Hcy determination in human blood.

scholarly journals Metabolite Profiling of Manilkara zapota L. Leaves by High-Resolution Mass Spectrometry Coupled with ESI and APCI and In Vitro Antioxidant Activity, α-Glucosidase, and Elastase Inhibition Assays

2020 ◽  
Vol 22 (1) ◽  
pp. 132
Author(s):  
Syful Islam ◽  
Md Badrul Alam ◽  
Hyeon-Jin Ann ◽  
Ji-Hyun Park ◽  
Sang-Han Lee ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
High Resolution Mass Spectrometry ◽  
Atmospheric Pressure Chemical Ionization ◽  
Ionization Mass ◽  
Manilkara Zapota ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical

High-resolution mass spectrometry equipped with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) sources was used to enhance the characterization of phytochemicals of ethanol extracts of Manilkara zapota L. leaves (ZLE). Sugar compounds, dicarboxylic acids, compounds of phenolic acids and flavonoids groups, and other phytochemicals were detected from the leaves. Antioxidant activity and inhibition potentiality of ZLE against α-glucosidase enzyme, and elastase enzyme activities were evaluated in in vitro analysis. ZLE significantly inhibited activities of α-glucosidase enzyme at a lower concentration (IC50 2.51 ± 0.15 µg/mL). Glucose uptake in C2C12 cells was significantly enhanced by 42.13 ± 0.15% following the treatment with ZLE at 30 µg/mL. It also exhibited potential antioxidant activities and elastase enzyme inhibition activity (IC50 27.51 ± 1.70 µg/mL). Atmospheric pressure chemical ionization mass spectrometry (APCI–MS) detected more m/z peaks than electrospray ionization mass spectrometry (ESI–MS), and both ionization techniques illustrated the biological activities of the detected compounds more thoroughly compared to single-mode analysis. Our findings suggest that APCI along with ESI is a potential ionization technique for metabolite profiling, and ZLE has the potential in managing diabetes by inhibiting α-glucosidase activity and enhancing glucose uptake.

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