Modification of sensitive pyridine-pyrazolone method for determination of blood cyanide and its possible applications in fatal aircraft accidents.

Background: Fatal aviation accidents are a critical concern for armed forces, necessitating precise toxicological analysis of postmortem blood samples. This paper introduces a novel spectrophotometric method for quantifying cyanide in blood samples with an aim to aid in aircraft accident reconstruction in the future.

Methods: Blood samples were collected from healthy non-smokers aged 20-45 years, excluding individuals with hepatic impairment, or those using drugs affecting blood cyanide levels. The spectrophotometric method involved cyanide adsorption in a sodium hydroxide solution using microdiffusion discs and chemical reactions resulting in a pinkish-purple end product. The optimal absorption wavelength ( ) was determined, and the lower limits of detection and quantitation were established. The method underwent validation for precision, sensitivity, specificity, linearity, and accuracy.

Results: The procedure yielded a pinkish-purple compound with an optimal absorption wavelength ( ) of 531 nm. The established limits of detection (LoD) and quantitation (LoQ) were 0.0625 μg/ml and 0.125 μg/ml, respectively. The method demonstrated strong linearity up to cyanide concentrations of 4 μg/ml. It exhibited a sensitivity of 99.7% and accuracy of 85.92%. The intraday and inter-day precision were determined as 9.04% and 4.27%, respectively. The method was highly specific, showing no interference with blanks at the peak wavelength with a working range of 0.125-4 μg/ml.

Conclusion: The study describes developing and validating a sensitive method for quantitatively estimating cyanide in blood samples. Incorporating this method into the existing postmortem toxicological sample collection and investigation protocol will enhance the analysis capabilities and improve aircraft accident investigation outcomes within the country.