Abstract
Production of methemoglobin (met Hb) is effective in treating or preventing cyanide intoxication due to the affinity of cyanide for met Hb. This paper describes an automated method for measuring met Hb in mouse blood utilizing the Roche COB AS FARA centrifugal analyzer and a modified Evelyn–Malloy procedure. Blood samples were spiked with various quantities of potassium ferricyanide to produce met Hb, and automated and manual analyses of these samples were compared. Following validation of the COB AS method, two known met Hb inducers, sodium nitrite and p-aminopropiophenone (PAPP), and two sulfur donor compounds, sodium thiosulfate and ICD #1021, not known to produce met Hb were tested in vivo. Five mice per compound were injected IP and blood samples were analyzed periodically over a time period of approximately 2 h. The automated technique requires only a drop of blood, which allows repeated sampling from the same animal, and can be adapted for blood from different species. A nalyses are rapid and sensitive, and results are reproducible.