Scott M. Ferko

On-line monitoring system for chemical warfare agents using automated capillary micellar electrokinetic chromatography

We present an automated analysis system for the detection of the chemical warfare blister agents, sulfur mustard (HD) and lewisite (L), in aqueous samples without any chemical derivatization. The system is compact in size and designed to operate in the field in a safe, autonomous manner for near real-time monitoring applications. It uses anionic surfactant-based capillary micellar electrokinetic chromatography (MEKC) to separate the sample followed by UV detection. The analysis time is sufficiently fast to allow direct detection of HD which enabled the estimation of effective hydrolysis rates in the aqueous sample matrix. The estimated hydrolysis half-life of HD in our system was 4.85 ± 0.05 min. The detection limit of HD was determined to be 10 ppm with a signal to noise ratio of 5. By contrast, L hydrolyzed too rapidly in aqueous samples to enable direct detection. Instead the first hydrolysis product 2-chlorovinyl arsonous acid (CVAA), also considered a blister agent, was detected with a detection limit of 0.7 ppm with a signal to noise ratio of 5.

Safety analysis of high pressure 3He-filled micro-channels for thermal neutron detection.

This document is a safety analysis of a novel neutron detection technology developed by Sandia National Laboratories. This technology is comprised of devices with tiny channels containing high pressure {sup 3}He. These devices are further integrated into large scale neutron sensors. Modeling and preliminary device testing indicates that the time required to detect the presence of special nuclear materials may be reduced under optimal conditions by several orders of magnitude using this approach. Also, these devices make efficient use of our {sup 3}He supply by making individual devices more efficient and/or extending the our limited {sup 3}He supply. The safety of these high pressure devices has been a primary concern. We address these safety concerns for a flat panel configuration intended for thermal neutron detection. Ballistic impact tests using 3 g projectiles were performed on devices made from FR4, Silicon, and Parmax materials. In addition to impact testing, operational limits were determined by pressurizing the devices either to failure or until they unacceptably leaked. We found that (1) sympathetic or parasitic failure does not occur in pressurized FR4 devices (2) the Si devices exhibited benign brittle failure (sympathetic failure under pressure was not tested) and (3) the Parmax devices failed unacceptably. FR4 devices were filled to pressures up to 4000 + 100 psig, and the impacts were captured using a high speed camera. The brittle Si devices shattered, but were completely contained when wrapped in thin tape, while the ductile FR4 devices deformed only. Even at 4000 psi the energy density of the compressed gas appears to be insignificant compared to the impact caused by the incoming projectile. In conclusion, the current FR4 device design pressurized up to 4000 psi does not show evidence of sympathetic failure, and these devices are intrinsically safe.

Engineered Improvement of the Generation-2 μChemlab™ Biotoxin Detector

The μChemLab™ program is developing hand-portable systems for detecting a broad range of chemical, biological, and viral agents in both gas and liquid samples. The μChem Lab liquid sample analyzer employs electrokinetic sample injection, chip-based electrophoretic microseparations and laser-induced florescence detection to analyze liquid samples. A second-generation liquid phase prototype is described. The device incorporates improvements from technological advances and applied research experience. New features include a modular design that readily accommodates on-chip preconcentration and additional separation techniques. The redesign reduces hardware failures, minimizes downtime during component replacement, improves usability, and provides increased sensitivity. Improvements have been made without compromising previous system performance.