The Analysis of Protein-Bound Thiocyanate in Plasma of Smokers and Non-Smokers as a Marker of Cyanide Exposure

When cyanide is introduced into the body, it quickly transforms through a variety of chemical reactions, normally involving sulfur donors, to form more stable chemical species. Depending on the nature of the sulfur donor, cyanide may be transformed into free thiocyanate, the major metabolite of cyanide transformation, 2-amino-2-thiazoline-4-carboxylic acid or protein-bound thiocyanate (PB-SCN) adducts. Because protein adducts are generally stable in biological systems, it has been suggested that PB-SCN may have distinct advantages as a marker of cyanide exposure. In this study, plasma was analyzed from 25 smokers (chronic low-level cyanide exposure group) and 25 non-smokers for PB-SCN. The amount of PB-SCN found in the plasma of smokers, 1.35 µM, was significantly elevated (p \u3c 0.0001) when compared to non-smokers, 0.66 µM. Differences in sub-groups of smokers and non-smokers were also evaluated. The results of this study indicate the effectiveness of analyzing PB-SCN in determining instances of chronic cyanide exposure with possible extension to confirmation of acute cyanide exposure

Determination of Cyanide Exposure by Gas Chromatography–mass Spectrometry Analysis of Cyanide-exposed Plasma Proteins

Exposure to cyanide can occur in a variety of ways, including exposure to smoke from cigarettes or fires, accidental exposure during industrial processes, and exposure from the use of cyanide as a poison or chemical warfare agent. Confirmation of cyanide exposure is difficult because, in vivo, cyanide quickly breaks down by a number of pathways, including the formation of both free and protein-bound thiocyanate. A simple method was developed to confirm cyanide exposure by extraction of protein-bound thiocyanate moieties from cyanide-exposed plasma proteins. Thiocyanate was successfully extracted and subsequently derivatized with pentafluorobenzyl bromide for GC–MS analysis. Thiocyanate levels as low as 2.5 ng mL−1 and cyanide exposure levels as low as 175 g kg−1 were detected. Samples analyzed from smokers and non-smokers using this method showed significantly different levels of protein-bound thiocyanate (p \u3c 0.01). These results demonstrate the potential of this method to positively confirm chronic cyanide exposure through the analysis of protein-bound cyanide in human plasma

Simultaneous Determination of Cyanide and Thiocyanate in Plasma by Chemical Ionization Gas Chromatography Mass-spectrometry (CI-GC-MS)

An analytical method utilizing chemical ionization gas chromatography-mass spectrometry was developed for the simultaneous determination of cyanide and thiocyanate in plasma. Sample preparation for this analysis required essentially one-step by combining the reaction of cyanide and thiocyanate with pentafluorobenzyl bromide and simultaneous extraction of the product into ethyl acetate facilitated by a phase-transfer catalyst, tetrabutylammonium sulfate. The limits of detection for cyanide and thiocyanate were 1 μM and 50 nM, respectively. The linear dynamic range was from 10 μM to 20 mM for cyanide and from 500 nM to 200 μM for thiocyanate with correlation coefficients higher than 0.999 for both cyanide and thiocyanate. The precision, as measured by %RSD, was below 9 %, and the accuracy was within 15 % of the nominal concentration for all quality control standards analyzed. The gross recoveries of cyanide and thiocyanate from plasma were over 90 %. Using this method, the toxicokinetic behavior of cyanide and thiocyanate in swine plasma was assessed following cyanide exposure

A Laboratory Exercise To Demonstrate the Theory and Practice of Analytical Sampling

In analytical chemistry classes, the importance of gathering a proper sample for analysis of bulk materials is often addressed only briefly or not at all. Although a number of classroom and laboratory exercises have been developed to illustrate factors that impact error introduced by sampling, they generally do not demonstrate the main goal of applying sampling theory for chemical analysis: determining the quantity of sample necessary to achieve a desired error. In this analytical laboratory exercise, students obtain representative samples by initial calculation of the quantity of bulk material to gather to achieve a predetermined sampling error. Students also evaluate some of the properties of a sample that contribute to sampling error. These concepts are introduced in the laboratory using simple surrogate samples and are then applied to a “realistic” scenario that also incorporates gravimetric analysis techniques