Objective:

To determine Sulphate ion concentration in sample by Turbidimetric method.

Apparatus used:

Spectrophotometer, Cuvettes, Pipette, Conical flasks, Magnetic stirrer, Spatula etc.

 Prepare a series of standards of 100ml by accurately pipetting calculated volumes of standard Sulphate solution to measure 5 to 40 mg/l in conical flasks.

Press the up arrow on the bulb

to take 5ml of Sulphate solution

up into the pipette

Press the down arrow on the bulb

to release Sulphate solution

into the flask

Dilute the solution by adding distilled water

 Prepare a blank solution and a sample solution by adding 100ml of distilled water and water sample to conical flasks respectively.

Press the up arrow on the bulb

to take distilled water up into

the pipette

Press the down arrow on the bulb

to release distilled water into

the flask

Dilute the solution by adding distilled water

Blank
Solution

Sample
Solution

 Add 20ml of Buffer solution to conical flasks.

Press the up arrow on the bulb

to take 20ml of Buffer solution

up into the pipette

Press the down arrow on the bulb

to release Buffer solution

into the flask

 Stir the solution in the flask using magnetic stirrer at constant speed.

 Add a spatula of Barium Chloride crystals. Then stir the solution for 60-65 seconds and allow it to rest for 5 minutes.

 Fill the cuvette with blank solution and place it in Spectrophotometer. Set the wavelength to 420nm by adjusting wavelength control knob.

 Fill the cuvette with Sulphate solution in the flask. Place it in Spectrophotometer and note down absorbance and transmittance values for each solution.