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Cyanide causes toxic effects by inhibiting cytochrome c oxidase, resulting in cellular hypoxia and cytotoxic anoxia, and can eventually lead to death. Cyanide exposure can be verified by direct analysis of cyanide concentrations or analyzing its metabolites, including thiocyanate (SCN(-)) and 2-amino-2-thiazoline-4-carboxylic acid (ATCA) in blood. To determine the behavior of these markers following cyanide exposure, a toxicokinetics study was performed in three animal models: (i) rats (250-300 g), (ii) rabbits (3.5-4.2 kg) and (iii) swine (47-54 kg). Cyanide reached a maximum in blood and declined rapidly in each animal model as it was absorbed, distributed, metabolized and eliminated. Thiocyanate concentrations rose more slowly as cyanide was enzymatically converted to SCN(-). Concentrations of ATCA did not rise significantly above the baseline in the rat model, but rose quickly in rabbits (up to a 40-fold increase) and swine (up to a 3-fold increase) and then fell rapidly, generally following the relative behavior of cyanide. Rats were administered cyanide subcutaneously and the apparent half-life (t1/2) was determined to be 1,510 min. Rabbits were administered cyanide intravenously and the t1/2 was determined to be 177 min. Swine were administered cyanide intravenously and the t1/2 was determined to be 26.9 min. The SCN(-) t1/2 in rats was 3,010 min, but was not calculated in rabbits and swine because SCN(-) concentrations did not reach a maximum. The t1/2 of ATCA was 40.7 and 13.9 min in rabbits and swine, respectively, while it could not be determined in rats with confidence. The current study suggests that cyanide exposure may be verified shortly after exposure by determining significantly elevated cyanide and SCN(-) in each animal model and ATCA may be used when the ATCA detoxification pathway is significant.

Although commonly known as a highly toxic chemical, cyanide is also an essential reagent for many industrial processes in areas such as mining, electroplating, and synthetic fiber production. The "heavy" use of cyanide in these industries, along with its necessary transportation, increases the possibility of human exposure. Because the onset of cyanide toxicity is fast, a rapid, sensitive, and accurate method for the diagnosis of cyanide exposure is necessary. Therefore, a field sensor for the diagnosis of cyanide exposure was developed based on the reaction of naphthalene dialdehyde, taurine, and cyanide, yielding a fluorescent β-isoindole. An integrated cyanide capture "apparatus", consisting of sample and cyanide capture chambers, allowed rapid separation of cyanide from blood samples. Rabbit whole blood was added to the sample chamber, acidified, and the HCN gas evolved was actively transferred through a stainless steel channel to the capture chamber containing a basic solution of naphthalene dialdehyde (NDA) and taurine. The overall analysis time (including the addition of the sample) was

A significant fraction of the total analysis time (injection-to-injection) in capillary electrophoresis is dedicated to a rigorous between-run capillary rinsing/regeneration procedure. This is of particular importance with CE-based assays developed for high-throughput analysis of clinical samples. In this study, we examine the necessity of a between-run rinsing step when detergent is present in the separation buffer. Using three model analyte systems (hypoglycemic drug standards, urinary estrogen standards, fasted normal human urine), the reproducibility for migration time (MT), peak area (PA), and peak height (PH) with separation in a borate/phosphate buffer containing 75 mM sodium cholate was found to be acceptable in the absence of between-run capillary cleansing. Continuous-sequential injection of hypoglycemic drug standards over the course of 39 consecutive runs without between-run capillary regeneration showed acceptable reproducibility. The average percent coefficient of variance values associated with [MT.sub.rel(MeOH)], PA, and PH over 39 consecutive runs were 2.22, 3.27, and 3.51%, respectively. In excess of 100 continuous-sequential injections could be performed in this manner without any significant effects on electroosmotic flow or reproducibility. Exclusivity of these results was ruled out with the continuous-sequential injection of the urinary estrogen and the human urine analyte systems under the same conditions, both of which yielded comparable results. The ability to circumvent or eliminate capillary rinsing procedures when detergent is a component of the separation buffer presents the possibility of decreasing the total analysis time (injection-to-injection) with certain analyte systems, the result of which will be to enhance sample throughput by 2-3-fold on single-capillary instrumentation.

Several biologically-active molecules differing only by a single hydroxyl group with nochange in net charge were subjected to high-performance capillary electrophoretic (HPCE) separation. Borate served as the buffer system in this process and was found to be essential in HPCE. Moreover, the possibility of HPCE in providing a unique approach for studying the equilibrium association ofborate with cis-diols is provided by its ability in monitoring the borate concentration-dependent complexation.

There is an escalating interest in the role of endogenous nitric oxide (NO) in biological systems and how this chemical regulates physiology in normal and disease states. In biological systems, the cellular concentration can be estimated, in the simplest form, by accounting for NO and its common metabolites, nitrate and nitrite. However, since NO is also known to interact with other chemical entities, such as thiols, it would be valuable to have a rapid qualitative assay that could account for thiol binding and S-N bond cleavage in the presence of different reducing agents. A separation buffer consisting of 10 mM phosphate, 10 mM HCl, and 250 mM KCl is shown to be adequate for the separation of glutathione, nitrosylated glutathione, and glutathione disulfide solubilized in 2 M HCl. The current observed under these separation conditions (249 [micro]A at 11 kV) is extremely high by capillary electrophoresis (CE) standards, with a total power (current voltage/capillary length) calculated to be in excess of 7 W/m. While this exceeds the ~1.0 W/m recommended by previous studies as a maximum for CE-based separations, we demonstrate that effective CE separation of thiols can, in fact, be accomplished under these conditions with acceptable reproducibility, provided that buffer depletion issues are addressed.