Development of a dual-chamber derivatization method for the determination of cyanide in sodium nitroprusside and its preparation via HS-GC-ECD

The acute toxicity of cyanide and its pharmaceutical residues, has fueled interest in the development of analytical methods for its determination, particularly for sodium nitroprusside (SNP), a widely used vasodilator with potential cyanide residues. In this study, a dual-chamber derivatization bottle was designed to establish an interconnected gas environment, thereby facilitating chloramine T-mediated cyanide conversion to cyanogen chloride (CNCl) without direct contact with SNP. Subsequent determination of the analytes was undertaken using a headspace gas chromatography electron capture detector (HS-GC-ECD). The challenges of analyzing cyanide and the rapid degradation of SNP were addressed simultaneously. The method was subjected to rigorous validation, encompassing specificity, linearity, limits of detection (LOD), limit of quantification (LOQ), accuracy, precision, and robustness. The validation process revealed a notable degree of linearity within the range of 0.012-1.56 μg/mL, with a LOQ of 12.0 ng/mL. The method was found to be both accurate and precise, thus satisfying the requisite criteria. This method facilitates reliable cyanide monitoring in degradation-prone pharmaceuticals.