SOP for Determination of Total Dissolved Solid
Scope
This method is applicable for the “determination Total dissolved solids” in water and waste water
Principle
The sample is filtered and the filtrate evaporated in a tared dish on steam-bath. The residue after evaporation is dried to constant mass at 103-105°C.
Apparatus
Glass fiber filter paper or Whatman 542 or membrane filter 0.45 mm, Filtration assembly, Vacuum Pump, Drying Oven, Desiccator, Analytical Balance
Procedure
- Heat the clean evaporating dish to 180°C for 1 hour in oven.
- Cool in the desiccator, weigh and store in the desiccator until ready for use.
- Filter the suitable volume of Sample through a filter paper (Glass Fiber filter or Whatman 542 or membrane filter 0.45 mm)
- Take Empty weight of Evaporating Dish.
- Take 25 ml of filtered sample to the previous weight Evaporating Dish.
- Evaporate the sample on the steam bath. Evaporation may also be performed in a drying oven. The temperature shall be lowered to approximately 98 deg C to prevent boiling and splattering of the sample.
- After complete evaporation of water from the residue. Transfer the dish to an oven at 103-105°C and dry to constant mass, take final weight after cooling in desiccator.
Calculation
TDS (mg/l) = Mass x 1000/Volume of Sample
Safety Guideline
Proper safety & health precaution are taken while doing the analysis by using safety goggles, apron, safety shoes & using fume chamber for fume generating chemicals, Gloves for oven.
Reference
IS 3025 (Part-16) 1984 RA: 2017