Hydrogen sensors and hydrogen-activated switches were fabricated from arrays of mesoscopic palladium wires. These "mesowire" prepared by electrodeposition onto graphite surfaces transferred a cyanoacrylate film. Exposure to hydrogen gas caused rapid (less than 75 milliseconds) reversible decrease in the resistance array that correlated with concentration over range 2 10%. The sensor response appears involve closing nanoscopic gaps or "break junctions" wires dilation grains undergoing...

Formation of nitrous acid (HONO) in the gas phase has been observed for first time a flow tube photoreactor upon irradiation (λ = 300–500 nm) 2-nitrophenol and methyl substituted derivatives using selective sensitive instrument (LOPAP) detection HONO. HONO by heterogeneous NO2 photochemistry excluded, since production under experimental conditions is negligible. Variation surface to volume ratio nitrophenol concentration showed that photolysis occurred indicating formation initiated...

A novel measurement setup is designed, constructed, and validated by theoretical simulations experiments enabling sensitive loss-free brake particle emission investigations. With the goal to simulate realistic driving, a 3 h subsection of Los Angeles City Traffic (LACT) cycle selected as test cycle. The tests are performed with front midsize passenger vehicle under both static laboratory more dynamic conditions that include parasitic drag temperatures (advanced simulations). PM10 factor...

Particle size distributions were measured under real world dilution conditions in the exhaust plume of a diesel passenger car closely followed by mobile laboratory on high speed test track. Under carefully controlled was continuously sampled and analyzed inside laboratory. Exhaust particle distribution data recorded together with gas concentrations, i.e., CO, CO2, NO(x), compared to obtained from same vehicle tested chassis dynamometer. Good agreement found for soot mode particles which...

The analysis of crude oil samples remains a tough challenge due to the complexity matrix and broad range physical chemical properties various individual compounds present. In this work, atmospheric pressure laser ionization (APLI) is utilized as complementary tool other techniques for analysis. Mass spectra obtained with electrospray (ESI) photoionization (APPI) are compared. APLI primarily sensitive towards non-polar aromatic hydrocarbons, which generally present in high amounts especially...

Methyl-2-nitrophenols can be emitted directly to the atmosphere or formed in situ via oxidation of aromatic hydrocarbons. Nitrophenols possess phytotoxic properties and recent studies indicate their photooxidation is effective producing secondary organic aerosols. Therefore, investigations on major pathways these compounds with respect assessing environmental impacts effects human health are highly relevant. Presented here determinations rate coefficients for reactions OH radicals four...

We report on the successful application of recently introduced atmospheric pressure laser ionization (APLI) method as a novel tool for analysis crude oil and its components. Using Fourier transform ion cyclotron resonance mass spectrometry, unambiguous determination key compounds in this complex matrix with unprecedented sensitivity is presented.

A novel, gas-tight API interface for gas chromatography-mass spectrometry was used to study the ionization mechanism in direct and dopant-assisted atmospheric pressure photoionization (APPI) laser (APLI). Eight analytes (ethylbenzene, bromobenzene, naphthalene, anthracene, benzaldehyde, pyridine, quinolone, acridine) with varying energies (IEs) proton affinities (PAs), four common APPI dopants (toluene, acetone, anisole, chlorobenzene) were chosen. All studied compounds ionized by APPI,...

Electrospray ionization (ESI) is one of the most prominent atmospheric pressure techniques in modern mass spectrometry. It generates charged droplets from an analyte-containing solution as initial step process. Textbooks and majority articles assume entire droplet evaporation release bare analyte ions within chamber. However, non-mass-spectrometry-related literature recent reports demonstrate observation regions vacuum systems a variety spectrometers. In this work, we report on large...

Electrospray ionization (ESI) is the most widely used technique for of liquid samples, example, from chromatography (LC) coupled to mass spectrometry. Recent experiments demonstrate penetration charged droplets or at least large clusters into high-vacuum region different ESI spectrometers. Using a Bruker micrOTOF equipped with standard Apollo source, we demonstrated that time-of-flight (TOF) MS can detect signatures these by analyzing statistics individual TOF spectra, resulting single...

Electrospray ionization is one of the most utilized techniques in atmospheric pressure mass spectrometry. Recent experimentally reported results are disagreement with fundamentals revolving around ESI droplet sizes and their lifetimes. Specifically, much larger longer lifetimes have been observed to exist typical ion sources. Experiments involving a custom scan mode on triple quadrupole system shown that high-mass fragments large droplets can be spectra. Initial hypotheses rationalizing...

The use of differential mobility spectrometry (DMS) as a separation tool prior to mass analysis has increased in popularity over the years. However, fundamental principles behind difference between high- and low-field is still matter debate—especially regarding strong impact solvent molecules added gas phase chemically modified DMS environments. In this contribution, we aim present thorough model for determination ion wide range field strengths subsequent calculation dispersion plots. Our...