How do you test for the presence of dissolved solids in water?

You can test for the presence of dissolved solids in water using a Total Dissolved Solids (TDS) meter.

A Total Dissolved Solids (TDS) meter is a handheld device that measures the total amount of mobile charged ions, including minerals, salts, or metals dissolved in a given volume of water. It is a simple and quick method to test for dissolved solids in water. The TDS meter works by applying a voltage between two or more electrodes placed in the water. The dissolved ions facilitate the flow of electricity, which is then measured by the meter. The reading is usually given in parts per million (ppm).

To use a TDS meter, you first need to turn it on and immerse it in the water sample. After a few seconds, the meter will display a reading. This reading represents the concentration of dissolved solids in the water. It's important to remember that the TDS meter does not identify the nature of the dissolved solids; it only measures their concentration.

Another method to test for dissolved solids is through evaporation. This involves taking a known volume of the water sample and evaporating it to dryness. The residue left behind represents the dissolved solids. By weighing this residue, you can calculate the concentration of dissolved solids in the water. However, this method is more time-consuming and requires more equipment than using a TDS meter.

In a laboratory setting, more sophisticated techniques such as spectrophotometry or chromatography can be used to not only detect but also identify and quantify the dissolved solids in water. These techniques, however, require specialised equipment and trained personnel.