Spectrophotometric determination of hemoglobin with p-acetylarsenazo

In a Britton-Robinson buffer medium at pH 2.87, hemoglobin can form a color compound with p-acetylarsenazo in the presence of emulgent OP. The maximum absorption locates at 370 nm. The apparent molar absorptivity epsilon(370 nm) is 4.11 X 10(5) L/(mol cm). Beer's law is obeyed over the range of 20-60 mg for hemoglobin. After the addition of a suitable amount of emulgent OP, the sensitivity and stability of the system can be obviously enhanced. Ethanol can increase the sensitivity of the system. Sodium chloride can enhance the sensitivity of the color system by 30%. The method has been applied to the determination of total proteins in human serums with satisfactory results.