TDS (Total Dissolved Solids)

October 10, 2016 11:20 am

Total Dissolved Solids is amount of dissolved solids present in the sample.

Definition

TDS is defined as materials that are completely dissolved in the sample in organic & inorganic form.

Range

Implications

Causes foaming in boilers and solids interfere with clearness, colour or taste of finished products. Low TDS value is required in most industries. High TDS leads to corrosion.

High level of specific ions included in the TDS measurement, such as nitrate, arsenic, aluminum, copper, or lead, could present health risks. Specific analysis needs to be carried out to determine potential health effects.

Sample Handling & Preservation

Once the sampling is done, analysis should be carried out as soon as possible; because biological activity will continue taking place after the sample has been taken. Changes may occur during handling & storage which might hinder the characteristics of the sample. To reduce the change in sample used for determination of TDS, it is advisable to keep the sample at 4⁰C. Care should be taken to prevent freezing of the sample.

Analysis Procedure

1. Switch on the balance (at least 30 mins before the test).
2. Weigh the crucible and note down the initial dry weight of the crucible.
3. Filter the sample using Whattman filter paper
4. Take 20 ml of filtered water sample in the crucible.
5. Place the crucible inside the oven at 103^oC
6. After drying it in the oven, place the crucible in the dessicator to cool it to the room temperature.
7. Weigh the crucible & note down the final dry weight of the crucible.

Calculation

• mg Dissolved Solids/L = (A - B) X 1000/ mL of sample
• where: A = weight of dried residue + crucible, mg
• B = weight of crucible, mg.

Interference:

• Dissolved minerals, gases & organic constituents may produce aesthetically displeasing colour, taste & odour.
• Some dissolved organic chemicals may deplete the dissolved oxygen in the receiving waters and some may be inert to biological oxidation, yet others have been identified as carcinogens
• In industries, use of high amount of dissolved solids may lead to scaling in boilers, corrosion & degraded quality of product.

Conclusion

This experiment estimates the total dissolved solids in the sample which helps to determine whether the sample is suitable for drinking purpose, agriculture & industrial purpose.

Disclaimer

The details given are for general understanding. References should be taken from respective authorized agencies.