Differentiating Writing Inks Using Direct Analysis in Real Time Mass Spectrometry

Writing ink analysis is used in establishing document authenticity and the sources and relative ages of written entries. Most analytical methods require removing samples or visibly altering the document. Nondestructive, in situ analysis of writing inks on paper without visible alteration is possible using mass spectrometry with a new ion source called Direct Analysis in Real Time. Forty-three different black and blue ballpoint, black fluid, and black gel inks were examined. Both dyes and persistent but thermally labile components of the inks contribute to the mass spectra, principally as protonated molecules [M1H]1. Numerous ink components were identified from the spectra. The spectra were placed in a searchable library, which was then challenged with two spectra from each of the 43 inks. The best match for each of the challenge spectra was correct for all but one ink, which matched with a very similar ink by the same manufacturer

Theory and Application of Dissociative Electron Capture in Molecular Identification

The coupling of an electron monochromator (EM) to a mass spectrometer (MS) has created a new analytical technique, EM-MS, for the investigation of electrophilic compounds. This method provides a powerful tool for molecular identification of compounds contained in complex matrices, such as environmental samples. EM-MS expands the application and selectivity of traditional MS through the inclusion of a new dimension in the space of molecular characteristics--the electron resonance energy spectrum. However, before this tool can realize its full potential, it will be necessary to create a library of resonance energy scans from standards of the molecules for which EM-MS offers a practical means of detection. Here, an approach supplementing direct measurement with chemical inference and quantum scattering theory is presented to demonstrate the feasibility of directly calculating resonance energy spectra. This approach makes use of the symmetry of the transition-matrix element of the captured electron to discriminate between the spectra of isomers. As a way of validating this approach, the resonance values for twenty-five nitrated aromatic compounds were measured along with their relative abundance. Subsequently, the spectra for the isomers of nitrotoluene were shown to be consistent with the symmetry-based model. The initial success of this treatment suggests that it might be possible to predict negative ion resonances and thus create a library of EM-MS standards.Comment: 18 pages, 7 figure

Rapid Screening and Quantification of Synthetic Cannabinoids in DART-MS and NMR Spectroscopy

The usage of herbal incenses intentionally doped with synthetic cannabinoids has caused an increase in medical incidents and has triggered legislation to ban these products throughout the world. Law enforcement agencies are experiencing sample backlogs due to the variety of the products and the addition of new and still-legal compounds. In our study, proton Nuclear Magnetic Resonance spectroscopy (NMR) was employed to promptly identify the synthetic cannabinoids after their rapid, direct detection on the herbs and in the powders by Direct Analysis in Real Time-Mass Spectrometry (DART-MS). Compared to conventional lengthy pre-NMR sample clean-up and purification, a simple sample preparation protocol was employed on 50 mg of herbal product samples for quick NMR detection. The combined DART-MS and NMR methods can be used to quickly screen synthetic cannabinoids in powder and herbal samples. Subsequently rapid quantification of cannabinoids can be achieved with short proton-NMR scans when an internal standard, maleic acid, is employed

763-1 Assessment of Left Ventricular Function by Circumferential Stress-Midwall Shortening Relations in Dilated Cardiomyopathy

Echocardiographic stress endocardial shortening relations provide estimates of LV contractility that do not uniformly detect myocardial dysfunction in dilated cardiomyopathy (DCM). Recently it has become apparent that midwall (mid) fractional shortening and circumferential (c) end-systolic stress (ESS) provide the most appropriate paired afterload and function measures. Both meridional (m) and cESS were related to both endocardial (e) FS and midFS in 42 patients with DCM (98% dead during follow-up; eFS =4% in the survivor) and in 140 normals. Eight patients (19%) fell into the 95% confidence interval of the normal relation of eFS to mESS (top panel), 14% had apparently normal midFS-mESS relations but midFS was depressed in relation to cESS in 100% of patients (lower panel). Thus, (1) use of cESS-shortening relations improves the ability to identify patients with depressed LV function; (2) use of midFS or eFS are equivalent in DCM with LV dilatation and wall thinning

Electron monochromator mass spectrometry for the analysis of whole bacteria and bacterial spores. Anal. Chem

Spores from a variety of Bacillus species were analyzed with direct probe mass spectrometry using an electron monochromator to select electrons of distinct energies for ionization. Electron energies were chosen to match the electron capture energies of taxonomically important compounds such as dipicolinic acid and fatty acids. Previous negative ion interferences were not observed when the monochromator was used, and the signal-tonoise ratio of targeted compounds was significantly enhanced using this approach. To demonstrate the selectivity of the technique, the monochromator was swept over a range of electron energies while monitoring the masses of compounds with known electron capture energies. Scanning the monochromator while the mass spectrometer was operated in single-ion mode enabled dipicolinic acid to be detected in 10 5 spores. The results presented here demonstrate the utility of the electron monochromator for selectively ionizing compounds directly in bacteria and bacterial spores

Proteomic analysis reveals metabolic and regulatory systems involved in the syntrophic and axenic lifestyle of Syntrophomonas wolfei

Microbial syntrophy is a vital metabolic interaction necessary for the complete oxidation of organic biomass to methane in all-anaerobic ecosystems. However, this process is thermodynamically constrained and represents an ecosystem-level metabolic bottleneck. To gain insight into the physiology of this process, a shotgun proteomics approach was used to quantify the protein landscape of the model syntrophic metabolizer, Syntrophomonas wolfei, grown axenically and syntrophically with Methanospirillum hungatei. Remarkably, the abundance of most proteins as represented by normalized spectral abundance factor (NSAF) value changed very little between the pure and coculture growth conditions. Among the most abundant proteins detected were GroEL and GroES chaperonins, a small heat shock protein, and proteins involved in electron transfer, beta-oxidation, and ATP synthesis. Several putative energy conservation enzyme systems that utilize NADH and ferredoxin were present. The abundance of an EtfAB2 and the membrane-bound iron-sulfur oxidoreductase (Swol_0698 gene product) delineated a potential conduit for electron transfer between acyl-CoA dehydrogenases and membrane redox carriers. Proteins detected only when S. wolfei was grown with M. hungatei included a zinc-dependent dehydrogenase with a GroES domain, whose gene is present in genomes in many organisms capable of syntrophy, and transcriptional regulators responsive to environmental stimuli or the physiological status of the cell. The proteomic analysis revealed an emphasis on macromolecular stability and energy metabolism by S. wolfei and presence of regulatory mechanisms responsive to external stimuli and cellular physiological status

An in vivo and in vitro trial of aclarubicin in metastatic breast cancer: a novel approach to the study of analogs

Aclarubicin is an anthracycline antibiotic that differs from doxorubicin in its structure, mechanism of action, and preclinical toxicity profile, especially its reduced cardiotoxicity. We therefore conducted a side-by-side in vivo and in vitro trial of this agent in metastatic breast-cancer patients and their biopsied tumor specimens, respectively. Aclarubicin (100 mg/m 2 ) was given by intravenous infusion every 3 weeks to 22 patients with objectively measurable metastatic breast cancer, 15 of whom had not previously received doxorubicin. The dose-limiting toxicity consisted primarily of leukopenia and severe nausea and vomiting. No objective response was observed in the 19 evaluable patients. After disease progression, 10 of the 15 doxorubicin-naive patients were treated with doxorubicin; 6 patients achieved a partial response, including 4 who responded to doxorubicin alone and 2 who responded to doxorubicin in combination with thiotepa and vinblastine. Tumor specimens were obtained from 14 of the 22 patients prior to the start of therapy and were tested for in vitro sensitivity to aclarubicin and doxorubicin using a soft agar colony-forming assay. Adequate colony growth occurred in 9 of 14 cultured tumor specimens. All 9 specimens, including 3 obtained from doxorubicin-naive patients, demonstrated in vitro resistance to aclarubicin. In all, 1 of 3 specimens taken from doxorubicin-naive patients demonstrated in vitro sensitivity to doxorubicin, whereas 6 tumor specimens obtained from patients who had undergone prior doxorubicin therapy demonstrated in vitro resistance. The patient whose tumor demonstrated in vitro doxorubicin sensitivity responded to a doxorubicin regimen after failing aclarubicin treatment; in vitro doxorubicin resistance correlated with clinical resistance in all cases. We conclude that aclarubicin is inactive in metastatic breast cancer at the dose and schedule used. Side-by-side in vivo and in vitro trials are feasible and could be useful in the development of investigational agents with activity greater than that of aclarubicin and, particularly, in the evaluation of analogs of clinically active drugs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46926/1/280_2004_Article_BF00685040.pd

Utilizing Weightlifting for Cycling Performance

Abstract available in the 9th Annual Coaches and Sport Science College