Platform for identification of Salmonella serovar differentiating bacterial proteins by top-down mass spectrometry: S. Typhimurium vs S. Heidelberg.

Intact protein expression profiling has proven to be a powerful tool for bacterial subspecies differentiation. To facilitate typing, epidemiology, and trace-back of Salmonella contamination in the food supply, a minimum of serovar level differentiation is required. Subsequent identification and validation of marker proteins is integral to rapid screening development and to determining which proteins are subject to environmental pressure.

Draft Genome Sequences of Two O104:H21 Escherichia coli Isolates Causing Hemorrhagic Colitis during a 1994 Montana Outbreak Provide Insight into Their Pathogenicity.

We sequenced the genomes of two strains of O104:H21 enterohemorrhagic Escherichia coli (EHEC) isolated during an outbreak of hemorrhagic colitis in Montana in 1994. These strains carried a plasmid that contains several virulence genes not present in pO157. The genome sequences will improve phylogenetic analysis of other non-O157 E.

A discriminant based charge deconvolution analysis pipeline for protein profiling of whole cell extracts using liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry.

A discriminant based charge deconvolution analysis pipeline is proposed. The molecular weight determination (MoWeD) charge deconvolution method was applied directly to the discrimination rules obtained by the fuzzy rule-building expert system (FuRES) pattern classifier. This approach was demonstrated with synthetic electrospray ionization-mass spectra.

Identification of the decarboxylated analog of tetrabromotetrachloro-fluorescein and its quantification in the color additives D&C Red Nos. 27 and 28 (phloxine B) using high-performance liquid chromatography.

The present work describes (a) the identification and characterization of an impurity, 2,4,5,7-tetrabromo-6-hydroxy-9-(2,3,4,5-tetrachlorophenyl)-3H-xanthen-3-one (BCPX), in the color additives D&C Red Nos. 27 and 28 (phloxine B) and (b) the determination of the extent and level of BCPX contamination in certified lots of these colors. For these purposes, BCPX (a compound not previously reported in the literature) was synthetically prepared.

Determination of 2,4,6-tribromoaniline in the color additives D&C Red Nos. 21 and 22 (Eosin Y) using solid-phase microextraction and gas chromatography-mass spectrometry.

The present work demonstrates the presence of an impurity, 2,4,6-tribromoaniline (TBA), in the color additives D&C Red Nos. 21 and 21 lake (21L) and describes the determination of TBA in certified lots of D&C Red Nos. 21, 21L and 22 (Eosin Y).

Analysis of coffee for the presence of acrylamide by LC-MS/MS.

A variety of popular instant, ground, and brewed coffees were analyzed using a modified liquid chromatography-tandem mass spectrometry (LC-MS/MS) method specifically developed for the determination of acrylamide in foods. Coffee test portions were spiked with 13C3-labeled acrylamide as an internal standard prior to their extraction and cleanup. Ground coffees (1 g) and instant coffees (0.

Rugged LC-MS/MS survey analysis for acrylamide in foods.

The described liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection of acrylamide in food entails aqueous room temperature extraction, SPE cleanup, and analysis by LC-MS/MS. The method is applicable to a wide variety of foods. [(13)C(3)]acrylamide is the internal standard.

Identification of 2-bromo-3,4,5,6-tetrachloroaniline and its quantification in the color additives D&C Red Nos. 27 and 28 (phloxine B) using solid-phase microextraction and gas chromatography-mass spectrometry.

The present work describes (a) the identification and characterization of a contaminant, 2-bromo-3,4,5,6-tetrachloroaniline (2BTCA), in the color additives D&C Red Nos. 27 and 28 (phloxine B) and (b) the determination of the extent and level of 2BTCA contamination in certified lots of these colors. For these purposes, 2BTCA (a compound not previously reported in the literature) and its positional isomer 4-bromo-2,3,5,6-tetrachloroaniline (4BTCA) were synthetically prepared.

Experimental factors affecting the quality and reproducibility of MALDI TOF mass spectra obtained from whole bacteria cells.

Numerous experimental factors are shown to significantly influence the spectra obtained when bacteria are analyzed by MALDI TOF/MS. Detailed investigation of the instrument parameters and sample preparation are all shown to influence the spectra. Of these, the preanalysis sample preparation steps incorporate the most important elements influencing the quality and reproducibility of the spectra.

Attachment of neutrals during tandem mass spectrometry of sulfonic acid dyes and intermediates in an ion trap.

Several positional isomers of 2-(2-quinolinyl)-1H-indene-1,3(2H)-dione mono- and disulfonic acids prepared as reference materials for development of analytical methods involved in FDA certification of D&C Yellow No. 10 (Quinoline Yellow) were found consistently to show [MH + 14](+) ions when their electrospray- or atmospheric pressure chemical ionization-prepared MH(+) ions were subjected to collisional activation. The source of these ions was found to be the methanol used as solvent in these procedures which combined with their [MH - H(2)O](+) ions under chemical ionization conditions.