Estimation of serum chloride

ESTIMATION OF SERUM CHLORIDE (Mercuric thiocyante method)

Principle:

Chloride ions react with a solution of mercuric thiocyanate and ferric nitrate to form undissociated mercuric chloride and a red brown ferric thiocyanate complex, which is quantitatively proportional to the chloride ion concentration.

                            2 Cl- + Hg (SCN)2 → HgCl2 + 2 (SCN)-

                            3 (SCN)- + Fe3+ → Fe (SCN)3

Reagents:

  • Color reagent (Mercuric thiocyante, Mercuric chloride, Ferric nitrate, Nitric acid, stabilizers, Surface active agents & inactive ingredients)
  • Chloride standard (100 mmol/l)

Procedure:

Pipette into two clean, dry test tubes labelled blank (B), standard (S), and test (T) as follows:

S.No
Reagents
B
S
T
1.
Chloride Reagent
1.0 ml
1.0 ml
1.0 ml
2.
Standard Chloride
-
10 m l
-
3.
Serum
-
-
10 m l
4.
Deionised water
1.5 ml
1.5 ml
1.5 ml

Mix well, wait for 1 minute at room temperature and read the absorbance of standard (S) and test (T) against blank at 510nm or with a green filter in a photoelectric colorimeter within 60 minutes.

Calculations :

Chloride (mmol/L) =                    O.D (T)

                                                     ----------- x 100

                                                         O.D (S)

Result:

The Chloride content of given serum = mmol / l or meq / l

Clinical Significance:

  • Chloride is a major extra cellular anion, which is significantly involved in the maintenance of water distribution, osmotic pressure and cation-anion balance in the extra cellular fluid compartment.
  • High serum values may be observed in dehydration and in conditions causing decreased renal blood flow such as congestive heart failure.
  • Low values may be observed in salt-losing nephritis, diabetic acidosis and renal failure. Lower CSF chloride values may be seen in meningitis, especially untreated tubercular meningitis.
Last modified: Monday, 4 June 2012, 6:03 AM