Quantification of expired metabolites following potassium cyanide administration: a new method.

A sensitive and specific radiolabel method for measuring expired hydrogen cyanide (HCN) or carbon dioxide (CO2) derived from cyanide was developed. An ethanol collecting solution containing a 10(-2) M of cobalt chloride trapped 88% of the H14CN passed through the solution following acid volatilization of a known amount of K14CN. The range of linearity, r = 0.998, exceeded the 0.01 to 0.1 mumoles tested for measuring the pulmonary metabolites. The cobalt chloride collecting solution trapped less than 0.02% of the 10 to 100 mumoles of 14CO2 generated by acid hydrolysis of 14C-sodium bicarbonate (NaH14CO3). Introduction of a second collecting solution specific for CO2, composed of ethanol: ethanolamine (2:1, v/v), was used to collect the CO2 derived from cyanide. Following the subcutaneous (sc) administration of 4.6 mg/kg of potassium cyanide (KCN) and 4.5 microcuries (microCi) K14CN, 1 to 2% and 2 to 3% of the dose was expired as H14CN and 14CO2, respectively.