Classification of local diesel fuels and simultaneous prediction of their physicochemical parameters using FTIR-ATR data and chemometrics.

Class identification and prediction of physicochemical variables of eight diesel fuel brands collected from several stations within the Atlanta metropolitan area in the State of Georgia were investigated using principal component analysis (PCA), partial least squares discriminant analysis (PLS2-DA), and partial least squares regression (PLSR) as modeling techniques. The fuels were from a common pipeline, therefore, assumed to have very similar characteristics. Ten FTIR-ATR spectra per fuel brand were collected over the 650 - 4000 cm mid-infrared region, and the 80 x 3351 matrix was submitted to PCA to determine if there were any clusters.

Laser-Induced Breakdown Spectroscopy for the Rapid Characterization of Lead-Free Gunshot Residues.

This study investigated the use of laser-induced breakdown spectroscopy (LIBS) and scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) as means of characterizing gunshot residue (GSR) originating from commercially available lead-free rounds. Data from two experiments are presented in this work. One experiment focused on identifying prominent analytical markers present in lead-free GSR by LIBS while the other applied SEM-EDX to determine the degree of evidence preservation after LIBS analysis.

Antibacterial Activities of Wasabi against O157:H7 and .

O157:H7 and are two of the major pathogens frequently involved in foodborne outbreaks. Control of these pathogens in foods is essential to food safety. It is of great interest in the use of natural antimicrobial compounds present in edible plants to control foodborne pathogens as consumers prefer more natural "green" foods.

Microextraction, capillary electrophoresis, and mass spectrometry for forensic analysis of azo and methine basic dyes from acrylic fibers.

Designed experiments based on a simplex mixture design were employed to explore the effects of three solvent components (water, formic acid, and aqueous acetic acid), extraction time, and extraction temperature for the automated microextraction of basic (cationic) dyes from acrylic fibers. Extractions were conducted by an automated liquid handling system, and dye extraction was evaluated using a UV/visible microplate reader. Highest extraction efficiency for two subclasses of basic dyes (methine and azo) from acrylic fibers was achieved with an extraction solvent containing 88% formic acid/12% water.

Forensic analysis of anthraquinone, azo, and metal complex acid dyes from nylon fibers by micro-extraction and capillary electrophoresis.

The extraction and separation of dyes present on textile fibers offers the possibility of enhanced discrimination between forensic trace fiber evidence. An automated liquid sample handling workstation was programmed to deliver varying solvent combinations to acid-dyed nylon samples, and the resulting extracts were analyzed by an ultraviolet/visible microplate reader to evaluate extraction efficiencies at different experimental conditions. Combinatorial experiments using three-component mixture designs varied three solvents (water, pyridine, and aqueous ammonia) and were employed at different extraction temperatures for various extraction durations.

Determining the lifetime of detectable amounts of gunshot residue on the hands of a shooter using laser-induced breakdown spectroscopy.

Laser-induced breakdown spectroscopy (LIBS) has been used to determine the period of time that a shooter will test positive for gunshot residue (GSR) after firing a revolver. Multiple rounds of primer were fired and samples collected at multiple hour intervals using an adhesive tape pressed against the skin. Samples were analyzed directly using a commercially available laser-induced breakdown spectrometer where barium emission (originating from barium nitrate in the primer) was observed.

Speciation of chromium via laser-induced breakdown spectroscopy of ion exchange polymer membranes.

A new method for the speciation of ng/mL concentrations of Cr(III) and Cr(VI) solutions with analysis by laser-induced breakdown spectroscopy (LIBS) is reported. Speciation is achieved by pre-concentration of the chromium onto commercially available cation exchange polymer membranes. Chromium(III) is removed directly by cation exchange; chromium(VI) in the filtrate is reduced to Cr(III) and concentrated onto a second cation exchange membrane, affording independent measurement of both species.

Laser-induced breakdown spectroscopy for the detection of gunshot residues on the hands of a shooter.

Laser-induced breakdown spectroscopy (LIBS) has been used to determine whether the hands of a suspected gun user contain traces of gunshot residue. Samples are obtained by pressing adhesive tape against the skin of the suspect and analyzing the tape directly. When the suspect has fired multiple shots, or if the gun has not been cleaned, the gunshot residue provides a spectral signature that is readily apparent, but a person who has fired a single shot from a clean gun is not so easy to identify.