Impact assessments detection limits

Validation of bioanalytical methods requires experiments to assess accuracy, precision, limit of detection, limit of quantitation, range, linearity, selectivity, and sample stability (23). The sample preparation step has a great impact on all these parameters. The extraction efficiency must be experimentally determined by comparison of extracted samples to unextracted standards (24,25). The unextracted standards, because of interference, must be diluted in saline or the mobile phase rather than plasma. 

Nonpulsatile optical spectroscopy has been used for more than half a century for noninvasive medical assessment, such as in the use of multiwavelength tissue analysis for oximetry and skin reflectance measurement for bilirubin assessment in jaundiced neonates. These early applications have found some limited use, but with modest impact. Recent investigations into new nonpulsatile spectroscopy methods for assessment of deep-tissue oxygenation (e.g., cerebral oxygen monitoring), for evaluation of respiratory status at the cellular level, and for the detection of other critical analytes, such as glucose, may yet prove more fruitful. The former applications have led to spectroscopic studies of cytochromes in tissues, and the latter has led to considerable work into new approaches in near-infrared analysis of intact tissues. 

The United States needs to improve and expand the uses of sensors in preventing terrorism and to minimize the impact should an incident occur. Besides point sampling devices, sensors to help provide sensitive and rapid detection and advance warning of toxic vapor at fixed sites such as subways, buildings, financial centers, and airports are of utmost importance. These sensors need to be operable around the clock. For example, sensors installed in the ventilation system could be coupled with a rapid shutdown procedure. Portable sensors to allow assessment from a remote or on-site point can be used to map the potential extent of the chanical cloud cover to aid authorities in organizing the movement of people. Current sensors have limited capabilities and must be improved. 

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