There are three types of sampling materials: solid, liquid, and gas. Solid samples can include sediment accumulated in water bodies, rocks, metals, and biological tissues.

Sediment in water bodies is extracted using a grab sampler or a piston corer. For example, after lowering a grab sampler to a riverbed, the sampler closes around the sediment to extract a sample.  

Some examples of liquid samples are water, blood, urine, and solvents. A precise volume of the homogeneous liquid is collected using a pipette or syringe.

Samples can be obtained from heterogeneous liquids like industrial effluents using an automated sampler, which collects them at regular intervals.

Gaseous samples can be collected from atmospheric air, exhaust vents, and industrial smokestacks for analysis.

Solid sorbents, such as activated carbon, are widely used to selectively adsorb target compounds from the gas stream. The target compound is then extracted by desorption techniques and analyzed via suitable analytical methods.