The Analysis of Cyanide and its Breakdown Products in Biological Samples

Cyanide is a toxic chemical that may be introduced into living organisms as a result of natural processes and/or anthropogenic uses (legal or illicit). Exposure to cyanide can be verified by analysis of cyanide or one of its breakdown products from biological samples. This verification may be important for medical, law-enforcement, military, forensic, research, or veterinary purposes. This review will discuss current bioanalytical techniques used for the verification of cyanide exposure, identify common problems associated with the analysis of cyanide and its biological breakdown products, and briefly address the metabolism and toxicokinetics of cyanide and its breakdown products in biological systems

Spectrophotometric Analysis of the Cyanide Metabolite 2-Aminothiazoline-4-Carboxylic Acid (ATCA)

Methods of directly evaluating cyanide levels are limited by the volatility of cyanide and by the difficulty of establishing steady-state cyanide levels with time. We investigated the measurement of a stable, toxic metabolite, 2-aminothiazoline-4-carboxylic acid (ATCA), in an attempt to circumvent the challenge of directly determining cyanide concentrations in aqueous media. This study was focused on the spectrophotometric ATCA determination in the presence of cyanide, thiocyanate (SCN−), cysteine, rhodanese, thiosulfate, and other sulfur donors. The method involves a thiazolidine ring opening in the presence of p-(hydroxy-mercuri)-benzoate, followed by the reaction with diphenylthiocarbazone (dithizone). The product is spectrophotometrically analyzed at 625 nm in carbon tetrachloride. The calibration curve was linear with a regression line of Y = 0.0022x (R2 = 0.9971). Interference of cyanide antidotes with the method was determined. Cyanide, thiosulfate, butanethiosulfonate (BTS), and rhodanese did not appreciably interfere with the analysis, but SCN− and cysteine significantly shifted the standard curve. This sensitive spectrophotometric method has shown promise as a substitute for the measurement of the less stable cyanide

Determination of the Cyanide Metabolite 2-Aminothiazoline-4-Carboxylic Acid in Urine and Plasma by Gas Chromatography–mass Spectrometry

The cyanide metabolite 2-aminothiazoline-4-carboxylic acid (ATCA) is a promising biomarker for cyanide exposure because of its stability and the limitations of direct determination of cyanide and more abundant cyanide metabolites. A simple, sensitive, and specific method based on derivatization and subsequent gas chromatography–mass spectrometry (GC–MS) analysis was developed for the identification and quantification of ATCA in synthetic urine and swine plasma. The urine and plasma samples were spiked with an internal standard (ATCA-d2), diluted, and acidified. The resulting solution was subjected to solid phase extraction on a mixed-mode cation exchange column. After elution and evaporation of the solvent, a silylating agent was used to derivatize the ATCA. Quantification of the derivatized ATCA was accomplished on a gas chromatograph with a mass selective detector. The current method produced a coefficient of variation of less than 6% (intra- and interassay) for two sets of quality control (QC) standards and a detection limit of 25 ng/ml. The applicability of the method was evaluated by determination of elevated levels of ATCA in human urine of smokers in relation to non-smokers for both males and females

Plasma Persistence of 2-Aminothiazoline-4-Carboxylic Acid in Rat System Determined by Liquid Chromatography Tandem Mass Spectrometry

2-Aminothiazoline-4-carboxylic acid (ATCA) was intravenously injected to rats in order to investigate its plasma distribution. ATCA was extracted from plasma samples by solid phase extraction (SPE) and molecularly imprinted polymer stir bar sorption extraction (MIP-SBSE). Detection and quantification of ATCA were achieved by using liquid chromatography–tandem mass spectrometry (LC–MS/MS). It was found that the intravenously injected ATCA concentration quickly decreased to half within 2.5 h in the rat system. However, after 2.5 h, the concentration of ATCA in plasma stayed constant at least 5 folds above the endogenous ATCA level for more then 48 h. This finding can be used for evaluating ATCA\u27s diagnostic and forensic value as a biomarker for cyanide exposure

'Ain't it a Ripping Night': Alcoholism and the Legacies of Empire in Salman Rushdie's Midnight's Children.

In the era of decolonisation that followed the Second World War, various authors sought to engage with India and the Empire’s past anew throughout their novels, identifying medicine and illness as key parts of Imperial authority and colonial experience. Salman Rushdie’s approach to the Raj in Midnight’s Children (1981) focused on the broad sweep of colonial life, juxtaposing the political and the personal. This article argues that Rushdie explores the history of colonial India by employing alcohol and alcoholism as lenses through which to explore the cultural, political and medical legacies of Empire. Through analysis of Midnight’s Children as well as a range of medical sources related to alcohol and inebriation, it will illustrate how drinking is central to Rushdie’s approach to secular and religious identities in newly independent India, as well as a means of satirising and undermining the supposed benefit that Empire presented to India and Indians