Publications by authors named "Pauline E Leary"

Fluorescence interference in Raman spectroscopy is a well-known problem and is especially significant in portable instruments where the availability of a variety of exciting wavelengths is unlikely. Several fluorescence avoidance and mitigation schemes are described in the literature, and implemented by Raman spectrometer manufacturers, but there is no standard method for evaluating the accuracy and repeatability of these schemes. Some test samples shown in instrument descriptions, such as "dark rum" and "sesame seed oil" are not reproducible.

View Article and Find Full Text PDF

The need to detect fentanyl and its analogs in the field is an important capability to help prevent unintentional exposure or overdose on these substances, which may result in death. Many portable methods historically used in the field by first responders and other field users to detect and identify other chemical substances, such as hazardous materials, have been applied to the detection and identification of these synthetic opioids. This paper describes field portable spectroscopic methods used for the detection and identification of fentanyl and its analogs.

View Article and Find Full Text PDF

Potent synthetic opioids including fentanyl and its analogs are frequently encountered in the field and require detection and identification by first responders to maintain the safety of drug abusers, first responders, health-care providers, and the public at large. Due to the low concentration at which these substances may be encountered and the complicating matrices within which they may be dispersed, the use of portable gas chromatography-mass spectrometry (GC-MS) for their identification in the field offers great potential value. This research established that portable GC-MS is a useful method for the detection and identification of a large number of synthetic opioids, especially fentanyl and its analogs.

View Article and Find Full Text PDF

The use of portable gas chromatography-mass spectrometry (GC-MS) is an important capability that has been available commercially for almost 25 years. These systems have been used within a variety of different industries, including their extensive use by environmental scientists for the analysis of hazardous air pollutants. Recently, these systems were deployed to conventional military forces for use in theater to detect and identify toxic chemicals including chemical warfare agents (CWAs).

View Article and Find Full Text PDF

Morphologically directed Raman spectroscopy (MDRS) is a novel tool for the forensic analysis of illicit and counterfeit drug samples. MDRS combines Raman microspectroscopy with automated particle imaging so that physical and chemical information about the components of a mixture sample can be obtained. Results of automated particle imaging are used to determine samples for Raman analysis.

View Article and Find Full Text PDF

The infrared (IR) microspectroscopical analysis of samples within a sealed-cell containing barium fluoride is a critical need when identifying toxic agents or suspicious powders of unidentified composition. The dispersive nature of barium fluoride is well understood and experimental conditions can be easily adjusted during reflection-absorption measurements to account for differences in focus between the visible and IR regions of the spectrum. In most instances, the ability to collect a viable spectrum is possible when using the sealed cell regardless of whether visible or IR focus is optimized.

View Article and Find Full Text PDF

Portable gas chromatography-mass spectrometry (GC-MS) systems are being deployed for field use, and are designed with this goal in mind. Performance characteristics of instruments that are successful in the field are different from those of equivalent technologies that are successful in a laboratory setting. These field-portable systems are extending the capabilities of the field user, providing investigative leads and confirmatory identifications in real time.

View Article and Find Full Text PDF

Drug release from four different poly(lactic-co-glycolic) acid (PLGA) microsphere formulations was evaluated under "real-time" (37 degrees C) and accelerated release testing conditions of elevated temperature (45, 53, 60 and 70 degrees C) and increase in flow rate (4-35 ml/min) using United States Pharmacopeia (USP) apparatus 4. Formulation 5 K (composed of low Mw PLGA) exhibited diffusion-controlled kinetics in "real-time". Whereas, formulations 25 K, 28 K and 70 K (composed of medium and high Mw PLGA) followed erosion-controlled kinetics at 37 degrees C.

View Article and Find Full Text PDF