Why N 10 HCl is used in Hb estimation?
Correspondingly, what is the principle of Haemoglobin estimation?
This is the internationally recommended method for determining hemoglobin. Principle: Blood is diluted in a solution containing potassium cyanide and potassium ferricyanide. The latter converts Hb to methemoglobin which is converted to cyanmethemoglobin (HiCN) by potassium cyanide.
Also question is, why only HCl is used in Sahli's method?
Concentrated acid if used in Sahli's method gives always the same colour for different hemoglobin concentrations, hence it can't be used for hemoglobin estimation.
Principle The Sahli method is based on converting hemoglobin to acid hematin and then visually matching its color against a solid glass standard. Dilute hydrochloric acid is added to a graduated cylinder containing a blood sample until the color of the diluted blood sample matches that of the glass standard.