Plasma Free Cyanide and Blood Total Cyanide: A Rapid Completely Automated Microdistillation Assay

Abstract

Techniques are presented which provide direct measurement of both free cyanide (CN-) in plasma and total CN- in whole blood. Loss of total CN- from blood is prevented by conversion to cyanmethemoglobin. Both free and total CN- are assayed by a completely automated method providing readout 17 minutes after sampling. No prior isolation technique is required and sensitivity is adjustable to cover a broad range of CN- concentrations from 1 to 4000 uM. Precision of blood CN- values from 2 to 2500 uM is within +/- 2.3%. No interference results from thiocyanate or thiosulfate at a concentration of approximately 1 mM.

The Analysis of Cyanide and its Breakdown Products in Biological Samples

“…The cyanogen halide is then reacted with an aromatic amine (normally pyridine) to produce an aldehyde product that is spectrophotometrically analyzed in the visible region. These methods have adequate sensitivity, but the products are unstable and they lack specificity due to interferences from other chemical species commonly present during the analysis of cyanide, especially thiocyanate and thiosulfate (175). Therefore, these methods often require microdiffusion sample preparation.…”

“…The determination of cyanide, thiocyanate, ATCA, and cyanide-protein adducts in biological fluids and tissues is useful for forensic, clinical, research, law enforcement, and veterinary purposes. Methods of analysis include spectrophotometry (37,59,62,74,78,81,89,90,93,105,120,130,133,139,141,143,, fluorescence (49,51,89,115,121,132,142,(175)(176)(177)(178)(179)(180)(181), chemiluminescence (77,109), electrochemistry (18, 56, 63-65, 68, 69, 73, 75, 79, 80, 106, 129, 138, 153, 182-197), gas chromatography (GC) (45, 53, 54, 61, 91, 95, 103-105, 107, 108, 111, 113, 114, 117, 119, 121, 125, 126, 128, 131, 135, 137, 152, 198-212), liquid chromatography (LC) (34,40,49,52,66,67,72,92,94,109,110,…”

Noninvasive In Vivo Monitoring of Cyanide Toxicity and Treatment Using Diffuse Optical Spectroscopy in a Rabbit Model

“…The only readily available methods to detect CN exposure are blood or urine CN level tests. 52 In addition to the previously mentioned limitations of blood cyanide level testing, 11,13 MetHb formation may actually increase measured blood CN levels from release of CN from cyanomethemoglobin during the assay process, despite reversing the toxic effects. 3,26 In contrast, noninvasive DOS methods are potentially capable of detecting the physiologic manifestations and biochemical effects of CN toxicity and treatment as seen in this study, even though blood levels of CN are not directly measured.…”

“…6 Accurate determination of blood CN levels are affected by both the time between exposure and specimen collection and the conditions of blood storage. 11–13 The cyanide molecule becomes unstable when exposed to temperatures higher than 4°C; therefore, the samples must be handled properly and processed expeditiously to ensure the accuracy of results. 14 Thus, the need for rapid identification of patients exposed to CN and the ability to continuously monitor response to treatment in a field or hospital setting is vital.…”

A partial exploration of the potential energy surfaces of SCN and HSCN: Implications for the enzyme-mediated detoxification of cyanide

“…The pathway to the right goes through the transition state species labeled TS2 leading to the much less stable species labeled SNC. anion [17]. Recent work by Logue and coworkers has examined thiocyanate content in the saliva of smokers using surfaceenhanced Raman spectroscopy [18].…”