Spectrophotometric measurement of carboxyhemoglobin and methemoglobin in blood.

This paper describes separate spectrophotometric procedures for rapidly measuring carboxyhemoglobin (COHb) and methemoglobin (MetHb) in blood. Absorbance measurements are made in the Soret region at a blood dilution near 1000-fold. For COHb estimation, the diluent contains sodium hydrosulfite, providing the two-component system COHb--Hb for absorbance measurements at 420 and 432 nm.

Molar absorbance of cyanmethemoglobin from blood of different animals.

The molar absorbance of cyanmethemoglobin at 540 nm was measured in 35 species of mammals, birds, and reptiles. Values obtained were compared with those measured on human cyanmethemoglobin by the same procedure. There was no significant difference (P greater than or equal to 0.

Analytical precautions in measurement of blood cyanide.

Solutions of KCN in 0.1 mol/liter NaOH, stored for six months at 4 degrees C, were unchanged as determined by silver titration and color development with pyridine-pyrazalone reagent. At room temperature the cyanide concentration of such solutions decreased by 0.

Determination of cyanide and nitroprusside in blood and plasma.

A procedure was refined for quantitative isolation of cyanide by gas transfer from acidified blood or plasma samples. The cyanide was trapped in dilute alkali and quantified as the pyridine/pyrazolone complex. The within-day coefficient of variation was 2%, which increased to about 2.