Analysis of suspicious powders following the post 9/11 anthrax scare.
BACKGROUND: Following the 9/11 terrorist attacks, SET Environmental, Inc., a Chicago-based environmental and hazardous materials management company received a large number of suspicious powders for analysis. METHODS: Samples of powders were submitted to SET for anthrax screening and/or unknown identification (UI). Anthrax screening was performed on-site using a ruggedized analytical pathogen identification device (R.A.P.I.D.) (Idaho Technologies, Salt Lake City, UT). UI was performed at SET headquarters (Wheeling, IL) utilizing a combination of wet chemistry techniques, infrared spectroscopy, and gas chromatography/mass spectroscopy. Turnaround time was approximately 2-3 hours for either anthrax or UI. RESULT: Between October 10, 2001 and October 11, 2002, 161 samples were analyzed. Of these, 57 were for anthrax screening only, 78 were for anthrax and UI, and 26 were for UI only. Sources of suspicious powders included industries (66%), U.S. Postal Service (19%), law enforcement (9%), and municipalities (7%). There were 0/135 anthrax screens that were positive. CONCLUSIONS: There were no positive anthrax screens performed by SET in the Chicago area following the post-9/11 anthrax scare. The only potential biological or chemical warfare agent identified (cyanide) was provided by law enforcement. Rapid anthrax screening and identification of unknown substances at the scene are useful to prevent costly interruption of services and potential referral for medical evaluation. (+info)
Surface chemistry effects on the performance of an electrochemical DNA sensor.
A novel poly(vinyl chloride) matrix membrane sensor for batch and flow-injection determinations of thiocyanate, cyanide and some metal ions.
A poly(vinyl chloride) matrix membrane sensor for the selective determination of thiocyanate has been developed based on the use of copper(II)-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex (Cu-PADAP) as a novel charged carrier, and o-nitrophenyloctyl ether (o-NPOE) as a solvent mediator. The sensor displays a significantly enhanced response towards SCN(-) ions over the concentration range 7.0 x 10(-6) to 1.0 x 10(-2) mol L(-1) with a detection limit of 5.6 x 10(-6) mol L(-1) and a calibration slope of -57.5 +/- 0.5 mV decade(-1). The sensor exhibits a long life-span, long-term stability, high reproducibility, and a fast response time. The selectivity coefficients of some anions were calculated using the separate solutions method, and found to be in the following order: SCN(-) > ClO(4)(-) > I(-) > Sal(-) > NO(2)(-) > Br(-) > NO(3)(-) = CH(3)COO(-) > Cl(-) > SO(4)(2-) = PO(4)(3-). The effects of the pH and ionic membrane additives (e.g. tridodecylmethylammonium chloride, TDMAC and potassium tetrakis[bis(3,5-trifluoromethyl)phenyl] borate, KTFPB) were examined. The sensor was used for the determination of SCN(-) ions in saliva and urine samples collected from some smoker and non-smoker donors. The developed sensor was also applied to determine the cyanide content in electroplating waste water samples after its conversion into thiocyanate. The application of the sensor to monitor the potentiometric titration of Ag(+) and Hg(2+) using SCN(-) resulted in sharp inflection breaks at the equivalent points. The data obtained using the proposed sensor correlate very well with results collected using the standard methods of thiocyanate, cyanide and metal analysis. (+info)
Chemical sensing based on catalytic nanomotors: motion-based detection of trace silver.
An electrochemical sensor for phenylephrine based on molecular imprinting.
Molecularly imprinted polymers (MIPs) were applied as molecular recognition elements to an electrochemical sensor for phenylephrine. A MIPs membrane was created on a glassy carbon electrode. SEM revealed a gradual change on the morphology of modified electrodes as the ratios of function monomer and cross-linking varied. When the ratio was 4:40, the surface morphology between the imprinted electrode (M-electrode) and the control electrode (N-electrode) became unambiguously different. This artificial receptor exhibited high selectivity for the template compared to closely related analogue. The response of the sensor varied in different concentration range might due to the heterogeneity of the MIPs membrane. This sensor was also used to determine phenylephrine in tablet samples. (+info)
The PedsQL in pediatric patients with Spinal Muscular Atrophy: feasibility, reliability, and validity of the Pediatric Quality of Life Inventory Generic Core Scales and Neuromuscular Module.