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Recent findings suggest that long-term exposure to diethyl phthalate (DEP), one of the widely used phthalate esters, can lead to serious health problems. Most perfumes contain non-negligible amounts of DEP. Rapid and sensitive detection of DEP in perfumes is thus of increasing importance. A novel procedure based on extractive electrospray ionization mass spectrometry (EESI-MS) has been developed for fast detection and identification of DEP in perfumes without the need for any sample pretreatment. The limit of determination for DEP in perfume was less than 100 ppb using tandem mass spectrometry on a commercial quadrupole time-of-flight mass spectrometer. The dynamic range of this method was about 4 orders of magnitude. A single sample analysis was completed within a few seconds, providing a rapid way to obtain semiquantitative information on the DEP content in perfumes. This study shows that both volatile and nonvolatile analytes (e.g., amino acids) in liquids can be directly sampled by neutral desorption, providing a convenient way for high-throughput screening of target compounds using EESI-MS.

Electron impact ionization has several known advantages; however, heated filament electron sources have pressure limitations and their power consumption can be significant for certain applications, such as in field-portable instruments. Herein, we evaluate a VUV krypton lamp as an alternative source for ionization inside the ion trap of a mass spectrometer. The observed fragmentation patterns are more characteristic of electron impact ionization than photoionization. In addition, mass spectra of analytes with ionization potentials higher than the lamp's photon energy (10.6 eV) can be easily obtained. A photoelectron impact ionization mechanism is suggested by the observed data allowed by the work function of the ion trap electrodes (4.5 eV), which is well within the lamp's photon energy. In this case, the photoelectrons emitted at the surface of the ion trap end-cap electrode are accelerated by the applied rf field to the ring electrode. This allows the photoelectrons to gain sufficient energy to ionize compounds with high ionization potentials to yield mass spectra characteristic of electron impact. In this manner, electron impact ionization can be used in ion trap mass spectrometers at low powers and without the limitations imposed by elevated pressures on heated filaments.

An instrument that combines near-field laser ablation at atmospheric pressure with an ion trap/time-of-flight mass spectrometer was developed. By coupling a UV laser into a fiber tip of a scanning near-field optical microscope, ablation craters much smaller than achievable with conventional laser optics can in principle be obtained. Laser ablation was performed on samples such as DHB, anthracene, and pyrene. Desorbed neutral analytes are transferred from atmospheric pressure to an ion trap, ionized, and stored. After 10 ms, the ions are extracted into a sensitive time-of-flight spectrometer. We demonstrate the feasibility of this unique SNOM-MS instrument for chemical analysis with unprecedented lateral resolution at atmospheric pressure. Spatially resolved molecular analysis with a lateral resolution of 5 [micro]m (fwhm) and a sensitivity of ~60 fmol of solid anthracene is demonstrated, along with topographical analysis with the same instrument. No other technique available today offers this lateral resolution in combination with soft mass spectrometry and the capability of sampling fragile specimens at atmospheric pressure.

In traditional luminol electrochemiluminescence (ECL) systems, hydrogen peroxide (H 2 O 2 ) and dissolved oxygen (DO) are the commonly used coreactants to generate reactive oxygen species (ROS) for ECL emission. However, the self-decomposition of hydrogen peroxide and the limited solubility and content of oxygen in solution undoubtedly restrict the luminescence efficiency and stability of the luminol ECL system. Inspired by the ROS-mediated ECL mechanism, we pioneered hydroxide ion as an advanced luminol ECL coreactant using nickel-doped and carbon nanotube-modified tungsten oxide (Ni-WO x -CNT) as the coreactant accelerator. Owing to the excellent catalytic activity of Ni-WO x -CNT, amounts of ROS were generated from OH - at a low excitation voltage, which subsequently reacted with luminol anion radicals and triggered intense ECL signals. Experiments confirmed an impressive ECL behavior in terms of high luminescent intensity (85,563 a.u.) and super stability over 1300 consecutive tests; both are superior to those recently reported luminol-H 2 O 2 and luminol-DO systems with smaller ECL intensities and consecutive tests less than 25 times. To validate the feasibility and versatility of the developed system in sensor, traditional three-electrodes system and closed bipolar electrodes system with various sensing strategies of direct oxidation, "gate-effect" of molecularly imprinted polymer, immune reaction, and enzyme-catalyzed reaction were proposed to monitor uric acid (UA), C-reactive protein (CRP), immunoglobulin G (IgG), and glucose (Glu). The superior sensing performances confirmed the great application potential of the developed ROS-mediated ECL system.