Serum Chloride

Question 0

Solution (Standard)

Answer 0

5 mL standard NaCl

0.4 mL s-diphenylcarbazone

Question 1

Color of undeteriorated s-diphenylcarbazone

Answer 1

Reddish-orange

Question 2

Prepared by adding 0.5 mL 2/3 N sulfuric acid and 0.5 mL 10% sodium tungstate to 1 mL serum and 8 mL distilled water

Answer 2

Folin-Wu protein-free filtrate

Question 3

Forms a lavender-colored complex

Answer 3

Excess of mercuric ions

Question 4

Reagents

Answer 4

1 Mercuric nitrate solution
2 2 N HNO3
3 S-diphenylcarbazone indicator, 0.1%
4 NaCl standard
5 H2SO4, 2/3 N
6 10% sodium tungstate

Question 5

Orange precipitate formed upon dilution

Answer 5

Mercuric oxide

Question 6

Reference range for 24 hour urine

Answer 6

11-250 mmol/day

Question 7

Titrant

Answer 7

Standard mercuric nitrate solution

Question 8

Procedure

Answer 8

1 Prepare a Folin-Wu protein-free filtrate
2 Label (2) Erlenmeyer flasks U and S and add solution
3 Using a 2 mL serological pipette, titrate both U and S to the lavender end point with mercuric nitrate solution and record the mL required to obtain the end point for each specimen

Question 9

Indicator

Answer 9

s-diphenylcarbazone

Question 10

Stability of indicator if stored in a brown bottle

Answer 10

Approx. 3-4 weeks

Question 11

Product of reaction of chloride with mercuric ions

Answer 11

Soluble but undissociated mercuric chloride

Question 12

Method

Answer 12

Schales and Schales Method

Question 12

Solution (Unknown)

Answer 12

5 mL PFF

0.4 mL s-diphenylcarbazone

Question 14

Principle

Answer 14

The sample is titrated with standard mercuric nitrate solution at the proper pH, in the presence of an indicator (s-diphenylcarbazone). The chloride present reacts with the mercuric ions in the mercuric nitrate solution to form soluble but undissociated mercuric chloride. When an excess of mercuric ions has been added a lavender-colored complex is formed. This is a mercurimetric procedure utilizing a direct titration.

Question 15

Calculations

Answer 15

1. (mL Hg(NO3)2 required to titrate unknown/mL Hg(NO3)2 required to titrate standard) x 5 mg/mL x 100/0.5 = mg Cl as NaCl/100 mL
2. Serum Cl = (mg % Cl x 10)/58.5
3. mg % Cl as NaCl x 10 = mEq/L

Question 16

Reference range for serum, plasma

Answer 16

98-107 mmol/L