Characterizing dynamic atmosphere generation system performance for analytical method development.

A significant portion of the work of developing and validating methods for volatile organic compound (VOC) sampling in workplace atmospheres involves the use of laboratory-generated atmospheres. The sample variability was evaluated from the dynamic atmosphere generation system used for VOC atmosphere generation and sampling. Characterization of the bias and variability of samples was done for a variety of atmospheres containing neat n-heptane and mixtures of VOCs sampled on activated coconut shell charcoal.

Evaluation of propylene glycol methyl ether as a potential challenge agent for leak detection of liquid and headspace from closed system drug transfer devices using Fourier transform infrared spectroscopy.

Choosing an appropriate surrogate of hazardous drugs for use in testing Closed System Drug-Transfer Devices (CSTDs) is a challenging endeavor with many factors that must be considered. It was suggested that the compound propylene glycol methyl ether (PGME) may meet many of the criteria we considered important in a suitable surrogate. Criteria included sufficient volatility to evaporate from aqueous liquid leaks efficiently, a Henry's constant which produced sufficient vapor phase concentrations to make headspace leaks detectable, and suitability for detection using a low-cost detection system.

A field-portable colorimetric method for the measurement of peracetic acid vapors: a comparison of glass and plastic impingers.

A method for measuring peracetic acid vapors in air using impinger sampling and field-portable colorimetric analysis is presented. The capture efficiency of aqueous media in glass and plastic impingers was evaluated when used for peracetic acid vapor sampling. Measurement of peracetic acid was done using an -diethyl-p-phenylenediamine colorimetric method with a field-portable spectrometer.

Source apportionment and quantification of liquid and headspace leaks from closed system drug-transfer devices via Selected Ion Flow Tube Mass Spectrometry (SIFT-MS).

A system to differentiate and quantify liquid and headspace vapor leaks from closed system drug-transfer devices (CSTDs) is presented. CSTDs are designed to reduce or eliminate hazardous drug (HD) exposure risk when compounding and administering HDs. CSTDs may leak liquid, headspace, or a mixture of the two.

Controlled generation of peracetic acid atmospheres for the evaluation of chemical samplers.

A system for controlled generation of peracetic acid (PAA) atmospheres used to test and evaluate sampling and measurement devices was developed and characterized. Stable atmospheric conditions were maintained in a dynamic flow system for hours while multiple sensors were simultaneously exposed to equivalent atmospheres of PAA vapors. Atmospheres characterized by a range of PAA concentrations at a controlled flow rate, temperature, and humidity were generated.

Assessing flammable storage cabinets as sources of VOC exposure in laboratories using real-time direct reading wireless detectors.

Herein we present the results of measurements using wireless direct-reading photoionization detector-based gas sensors to quantify concentrations of vapors of volatile organic compounds (VOCs) in and around flammable storage cabinets containing common organic solvents, including acetone, dichloromethane, trichloroethylene, and benzene. Such cabinets are commonly employed in laboratories to contain flammable liquids. A sensor array was deployed in a series of flammable storage cabinets in working laboratories.

A system for characterizing Mg corrosion in aqueous solutions using electrochemical sensors and impedance spectroscopy.

Understanding Mg corrosion is important to the development of biomedical implants made from Mg alloys. Mg corrodes readily in aqueous environments, producing H2, OH- and Mg2+. The rate of formation of these corrosion products is especially important in biomedical applications where they can affect cells and tissue near the implant.

Carbohydrate-based label-free detection of Escherichia coli ORN 178 using electrochemical impedance spectroscopy.

A label-free biosensor for Escherichia coli (E. coli) ORN 178 based on faradaic electrochemical impedance spectroscopy (EIS) was developed. α-Mannoside or β-galactoside was immobilized on a gold disk electrode using a self-assembled monolayer (SAM) via a spacer terminated in a thiol functionality.

N-acetylaspartate as a reservoir for glutamate.

N-acetylaspartate (NAA) is an intermediary metabolite that is found in relatively high concentrations in the human brain. More specifically, NAA is so concentrated in the neurons that it generates one of the most visible peaks in nuclear magnetic resonance (NMR) spectra, thus allowing NAA to serve as "a neuronal marker". However, to date there is no generally accepted physiological (primary) role for NAA.