Autonomous, broad-spectrum detection of hazardous aerosols in seconds.

Actual or surrogate chemical, biological, radiological, nuclear, and explosive materials and illicit drug precursors can be rapidly detected and identified when in aerosol form by a Single-Particle Aerosol Mass Spectrometry (SPAMS) system. This entails not only the sampling of such particles but also the physical analysis and subsequent data analysis leading to a highly reliable alarm state. SPAMS hardware is briefly reviewed.

Parameters contributing to efficient ion generation in aerosol MALDI mass spectrometry.

The Bioaerosol Mass Spectrometry (BAMS) system was developed for the real-time detection and identification of biological aerosols using laser desorption ionization. Greater differentiation of particle types is desired; consequently MALDI techniques are being investigated. The small sample size ( approximately 1 microm3), lack of substrate, and ability to simultaneously monitor both positive and negative ions provide a unique opportunity to gain new insight into the MALDI process.

Single-particle aerosol mass spectrometry for the detection and identification of chemical warfare agent simulants.

Single-particle aerosol mass spectrometry (SPAMS) was used for the real-time detection of liquid nerve agent simulants. A total of 1000 dual-polarity time-of-flight mass spectra were obtained for micrometer-sized single particles each of dimethyl methyl phosphonate, diethyl ethyl phosphonate, diethyl phosphoramidate, and diethyl phthalate using laser fluences between 0.58 and 7.

Online aerosol mass spectrometry of single micrometer-sized particles containing poly(ethylene glycol).

The analysis of poly(ethylene glycol) (PEG)-containing particles by online single particle aerosol mass spectrometers equipped with laser desorption/ionization (LDI) is reported. We demonstrate that PEG-containing particles are useful in the development of aerosol mass spectrometers because of their ease of preparation, low cost, and inherently recognizable mass spectra. Solutions containing millimolar quantities of PEGs were nebulized and, after drying, the resultant micrometer-sized PEG-containing particles were sampled.

Identification of high explosives using single-particle aerosol mass spectrometry.

The application of single-particle aerosol mass spectrometry (SPAMS) to the real-time detection of micrometer-sized single particles of high explosives is described. Dual-polarity time-of-flight mass spectra from 1000 single particles each of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN), as well as those of complex explosives, Composition B, Semtex 1A, and Semtex 1H, were obtained over a range of desorption/ionization laser fluences between 0.50 and 8.

Following the biochemical and morphological changes of Bacillus atrophaeus cells during the sporulation process using Bioaerosol Mass Spectrometry.

Bioaerosol Mass Spectrometry (BAMS), a real-time single cell analytical technique, was used to follow the biochemical and morphological changes within a group of Bacillus atrophaeus cells by measuring individual cells during the process of sporulation. A mutant of B. atrophaeus that lacks the ability to produce dipicolinic acid (DPA) was also analyzed.

Desorption/ionization fluence thresholds and improved mass spectral consistency measured using a flattop laser profile in the bioaerosol mass spectrometry of single Bacillus endospores.

Bioaerosol mass spectrometry is being developed to analyze and identify biological aerosols in real time. Mass spectra of individual Bacillus endospores were measured with a bipolar aerosol time-of-flight mass spectrometer in which molecular desorption and ionization were produced using a single laser pulse from a Q-switched, frequency-quadrupled Nd:YAG laser that was modified to have an approximately flattop profile. The flattened laser profile allowed the minimum fluence required to desorb and ionize significant numbers of ions from single aerosol particles to be determined.

Bioaerosol mass spectrometry for rapid detection of individual airborne Mycobacterium tuberculosis H37Ra particles.

Single-particle laser desorption/ionization time-of-flight mass spectrometry, in the form of bioaerosol mass spectrometry (BAMS), was evaluated as a rapid detector for individual airborne, micron-sized, Mycobacterium tuberculosis H37Ra particles, comprised of a single cell or a small number of clumped cells. The BAMS mass spectral signatures for aerosolized M. tuberculosis H37Ra particles were found to be distinct from M.

Improved sensitivity and mass range in time-of-flight bioaerosol mass spectrometry using an electrostatic ion guide.

Bioearosol mass spectrometry (BAMS) analyzes single particles in real time from ambient air, placing strict demands on instrument sensitivity. Modeling of the BAMS reflectron time of flight (TOF) with SIMION revealed design limitations associated with ion transmission and instrument sensitivity at higher masses. Design and implementation of a BAMS linear TOF with electrostatic ion guide and delayed extraction capabilities has greatly increased the sensitivity and mass range relative to the reflectron design.

Achieving high detection sensitivity (14 zmol) of biomolecular ions in bioaerosol mass spectrometry.

Bioaerosol mass spectrometry (BAMS) performs single-cell analysis in real time. However, the specificity of BAMS mass signatures has been limited by low sensitivity at high masses. To increase the mass range and sensitivity of BAMS, a novel design was developed that utilizes a linear flight tube with delayed extraction and an electrostatic ion guide.

Comprehensive assignment of mass spectral signatures from individual Bacillus atrophaeus spores in matrix-free laser desorption/ionization bioaerosol mass spectrometry.

We have fully characterized the mass spectral signatures of individual Bacillus atrophaeus spores obtained using matrix-free laser desorption/ionization bioaerosol mass spectrometry (BAMS). Mass spectra of spores grown in unlabeled, 13C-labeled, and 15N-labeled growth media were used to determine the number of carbon and nitrogen atoms associated with each mass peak observed in mass spectra from positive and negative ions. To determine the parent ion structure associated with fragment ion peaks, the fragmentation patterns of several chemical standards were independently determined.

Stable isotope labeling of entire Bacillus atrophaeus spores and vegetative cells using bioaerosol mass spectrometry.

Single vegetative cells and spores of Bacillus atrophaeus, formerly Bacillus subtilis var. niger, were analyzed using bioaerosol mass spectrometry. Key biomarkers were identified from organisms grown in 13C and 15N isotopically enriched media.

Toward understanding the ionization of biomarkers from micrometer particles by bio-aerosol mass spectrometry.

The appearance of informative signals in the mass spectra of laser-ablated bio-aerosol particles depends on the effective ionization probabilities (EIP) of individual components during the laser ionization process. This study investigates how bio-aerosol chemical composition governs the EIP values of specific components and the overall features of the spectra from the bio-aerosol mass spectrometry (BAMS). EIP values were determined for a series of amino acid, dipicolinic acid, and peptide aerosol particles to determine what chemical features aid in ionization.

Reagentless detection and classification of individual bioaerosol particles in seconds.

The rapid chemical analysis of individual cells is an analytical capability that will profoundly impact many fields including bioaerosol detection for biodefense and cellular diagnostics for clinical medicine. This article describes a mass spectrometry-based analytical technique for the real-time and reagentless characterization of individual airborne cells without sample preparation. We characterize the mass spectral signature of individual Bacillus spores and demonstrate the ability to distinguish two Bacillus spore species, B.

Laser power dependence of mass spectral signatures from individual bacterial spores in bioaerosol mass spectrometry.

Bioaerosol mass spectrometry is being developed to analyze and identify biological aerosols in real time. Characteristic mass spectra from individual bacterial endospores of Bacillus subtilis var. niger were obtained in a bipolar aerosol time-of-flight mass spectrometer using a pulsed 266-nm laser for molecular desorption and ionization.