The fragmentation behavior of the 2+ and 3+ charge states of eleven different phosphorylated tau peptides was studied using collision-induced dissociation (CID), electron transfer dissociation (ETD) and metastable atom-activated dissociation (MAD). The synthetic peptides studied contain up to two known phosphorylation sites on serine or threonine residues, at least two basic residues, and between four and eight potential sites of phosphorylation. CID produced mainly b-/y-type ions with abundant neutral losses of the phosphorylation modification. ETD produced c-/z-type ions in highest abundance but also showed numerous y-type ions at a frequency about 50% that of the z-type ions. The major peaks observed in the ETD spectra correspond to the charge-reduced product ions and small neutral losses from the charge-reduced peaks. ETD of the 2+ charge state of each peptide generally produced fewer backbone cleavages than the 3+ charge state, consistent with previous reports. Regardless of charge state, MAD achieved more extensive backbone cleavage than CID or ETD, while retaining the modification(s) in most cases. In all but one case, unambiguous modification site determination was achieved with MAD. MAD produced 15-20% better sequence coverage than CID and ETD for both the 2+ and 3+ charge states and very different fragmentation products indicating that the mechanism of fragmentation in MAD is unique and complementary to CID and ETD.

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We present the development of a new, faster analytical method for the determination of fatty acid ethyl esters (FAEEs) in human hair to detect potential alcohol abuse. FAEEs have been established as metabolites of ethanol consumption in humans and are embedded in the hair follicles during hair growth. The developed method has a total analysis time-including washing, extraction, concentration, separation, and detection-of less than 1 hour. Commonly used extraction procedures in the literature for these biomarkers are typically 15 hours. Analysis is performed using gas chromatography-tandem mass spectrometry (GC-MS/MS) with a GC separation time of less than 9 minutes. Using chemical ionization, mass spectrometric detection consists of selected reaction monitoring, which is widely considered to be one of the most selective and sensitive forms of mass spectrometric detection. Employing selected reaction monitoring helps to reduce interferences from the hair matrix, thereby making the method more selective for these biomarkers of interest. Limits of detection for each FAEE range from 0.002 to 0.030 ng/mg in hair. By using this faster extraction method, this research shows that this method could potentially be used to distinguish whether a person is a heavy drinker, moderate drinker, or nondrinker. The ability to rapidly analyze hair samples can be applied to a number of different areas, such as neonatal screening, parole violations, contributing factors in the cause of death, and any other application requiring the establishment of chronic versus acute alcohol abuse.

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This paper describes the sequence of analyses used to determine the nature of a stain located on the floor of room in the former Athens Mental Health and Retardation Hospital in Athens, OH. The location of the stain was reported to be the position in which a decomposing body was discovered on January 11, 1979. The current stain is found to contain strong evidence for both natural decomposition products and deliberate adulteration. Microscopic analyses, solubility tests, FTIR, ICP-OES, pyrolysis-MS, and derivatization GC-MS were consistent in determining the removable parts of the stain to be composed mostly of calcium and sodium salts of free fatty acids, such as palmitic acid, consistent with previous descriptions of adipocere. The free fatty acids could have been formed via known bacterial degradation pathways or via saponification through the basic environment caused through contact with the concrete. To our knowledge, adipocere formation on an exposed indoor environment has not been described before. The stain and concrete also show signs of being chemically modified with an acidic reagent, such as Blu-Lite--a phosphoric acid-based cleaner that was a commonly used cleaner in the building from the time of discovery to the present day. The chemical etching appears to have been restricted to an area resembling the shape of a human body, which is consistent with deliberate adulteration of the appearance of the stain.