Leonard A. Dillon, Victoria N. Stone, Laura A. Croasdell, Peter R. Fielden, Nicholas J. Goddard and C. L. Paul Thomas

An electrospray ionisation triple quadrupole mass spectrometer (Varian 1200 L) was modified to accept nitrogen samples containing low concentrations of volatile organic compounds. Six candidate probe compounds, methyl decanoate, octan-3-one, 2-ethylhexanoic acid, 1,4-diaminobutane, dimethyl methylphosphonate, and 2,3-butanediol, at concentrations below 50 ppb(v) were generated with permeation tubes in a test atmosphere generator.

Zhongchen Wu, Konstantin Chingin, Huanwen Chen, Liang Zhu, Bin Jia, R. Zenobi

The development of analytical techniques suitable for sensitive, high-throughput, and nondestructive food analysis has been of increasing interest in recent years. In this study, mass-spectral fingerprints of various cheese products were rapidly recorded in the mass range of m/z 50-300 Da without any sample pretreatment, using ND-EESI-MS in negative ion mode.

J. C. Reynolds,* G. J. Blackburn, C. Guallar-Hoyas, V. H. Moll, V. Bocos-Bintintan, G. Kaur-Atwal, M. D. Howdle, E. L. Harry, L. J. Brown, C. S. Creaser, and C. L. P. Thomas

A thermal desorption unit has been interfaced to an electrospray ionization-ion mobility-time-of-flight mass spectrometer. The interface was evaluated using a mixture of six model volatile organic compounds which showed detection limits of <1 ng sample loaded onto a thermal desorption tube packed with Tenax, equivalent to sampled concentrations of 4 μg L−1. Thermal desorption profiles were observed for all of the compounds, and ion mobility-mass spectrometry separations were used to resolve the probe compound responses from each other…

P. M-L Sinues

We investigated the volatile organic compounds emanated from the hand of two individuals, on-line by secondary electrospray ionization-mass spectrometry in positive ionization mode. The background ambient air is continuously sampled, ionized and readily mass analyzed. When the probe samples above the headspace of the hand of two subjects, several peaks …

P. M-L Sinues, J. F. de la Mora

Vapors released by the skin in the hand of one human subject are detected in real time by sampling them directly from the ambient gas surrounding the hand, ionizing them by secondary electrospray ionization (SESI, via contact with the charged cloud from an electrospray source), and analyzing them in a mass spectrometer with an atmospheric pressure source (API-MS).

P. M-L Sinues, J. Rus, G. F. de la Mora, M. Hernández, and J. F. de la Mora

We determine the sensitivity of several commercial atmospheric pressure ionization mass spectrometers towards ambient vapors, ionized by contact with an electrospray of acidified or ammoniated solvent, a technique often referred to as secondary electrospray ionization (SESI).

H. Chen, R. Zenobi

Extractive electrospray ionization mass spectrometry (EESI-MS) allows the real-time, direct analysis of complex gaseous and liquid samples without any sample pretreatment under ambient conditions. By using a neutral desorption (ND) sampling gas beam to gently impact a surface, the analyte present on a surface can be efficiently sampled and then transported …

P. M-L Sinues, J. F. de la Mora

Real time analysis of human breath is achieved in an atmospheric pressure ionization mass spectrometer (API-MS) by negatively charging exhaled vapors via contact with an electrospray cloud. The spectrum observed is dominated by a wide range of deprotonated fatty acids, including saturated chains up to C14. Above C14, the background from cutaneous sources becomes dominant.

L. Zhu, G. Gamez, H. W. Chen, H. X. Huang, K. Chingin and Renato Zenobi

Extractive electrospray ionization mass spectrometry (EESI-MS) for real-time monitoring of organic chemical reactions was demonstrated for a well-established pharmaceutical process reaction and a widely used acetylation reaction in the presence of a nucleophilic catalyst, 4-dimethylaminopyridine (4-DMAP) …

L. Zhu, G. Gamez, H. W. Chen, H. X. Huang, K. Chingin and Renato Zenobi

Extractive electrospray ionization mass spectrometry (EESI-MS) for real-time monitoring of organic chemical reactions was demonstrated for a well-established pharmaceutical process reaction and a widely used acetylation reaction in the presence of a nucleophilic catalyst, 4-dimethylaminopyridine (4-DMAP) …

H. Chen and R. Zenobi

Spinach contaminated with E. coli leaves 200 people sick in the USA – rapid screening needed for suspected food! Epidemic − thousands of patients need to be rapidly screened in emergencies… What do these and similar headlines have in common? They all challenge modern analytical science in terms of sensitivity, specificity, speed, and especially throughput. It appears that …

H. Chen, S. Yang, A. Wortmann, and R. Zenobi

Mass spectrometry is increasingly used for research purposes and routine measurements in biology, life science, the pharmaceutical industry, and in clinic diagnosis to characterize complex samples. Usually, biological samples are mixtures supported by a biological structure such as skin, tissue, muscle, or vessels and are commonly accompanied by microorganisms …

H. Chen, A. Wortmann, Renato Zenobi

It is of increasing interest and practical importance to develop convenient methods based on mass spectrometry for high-throughput analyses of biological samples. This is usually difficult because of the complex matrix and ion suppression effects. Generation of ions at ambient conditions is a promising solution to these problems …

H. Chen, Y. Sun, A. Wortmann, H. Gu, R. Zenobi

Maturity is an essential factor that determines storage life and final quality of most fruits and vegetables. Maturity monitoring is thus of paramount importance for postharvest handling and fruit quality regulation. Ideal analytical procedures for maturity investigation require high sensitivity, specificity, and high throughput and should be noninvasive.

P. M-L Sinues, J. F. de la Mora

Recent work by Zenobi and colleagues reports that human breath charged by contact with an electrospray (ES) cloud yields many mass peaks of species such as urea, glucose, and other ions, some with molecular weights above 1000Da.

H. Chen, D. Touboul,M. C. Jecklin, J. Zheng, M. Luoa, Renato Zenobid

A home-made extractive electrospray ionization source is coupled to a linear quadrupole ion trap mass spectrometer to investigate ion/molecule reactions of biopolymers at ambient pressure. Multiply charged biopolymers such as peptides and proteins generated in an electrospray are easily reduced to a low charge state by …

H. Chen, A. Wortmann, W. Zhang, and R. Zenobi

Quantitative analysis of trace constituents in exhaled gas can provide useful insights into biochemical processes in the body, thus revealing information about metabolic dynamics and providing, theoretically, a scientific base for biomarker research or clinical diagnoses. Breath, however, is rarely used practically for diagnostic purposes in clinical medicine …

M. Tam and H. H. Hill, Jr.

The unique capability of secondary electrospray ionization (SESI) as a nonradioactive ionization source to detect analytes in both liquid and gaseous samples was evaluated using aqueous solutions of three common military explosives: cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), nitroglycerin (NG) and pentaerythritol tetranitrate (PETN).

W. E. Steiner, B. H. Clowers, P. E. Haigh, and H. H. Hill

For the first time, the use of a traditional ionization source for ion mobility spectrometry (radioactive nickel (63Ni) beta emission ionization) and three alternative ionization sources (electrospray ionization (ESI), secondary electrospray ionization (SESI), and electrical discharge (corona) ionization (CI)) were employed with …

C. Wu, W. F. Siems, and H. H. Hill, Jr.

A secondary electrospray ionization (SESI) method was developed as a nonradioactive ionization source for ion mobility spectrometry (IMS). This SESI method relied on the gas-phase interaction between charged particles created by electrospray ionization (ESI) and neutral gaseous sample molecules. Mass spectrometry (MS) was used as …