How composition of POC is determined? Orsat analysis

Composition of POC is determined by “Orsat Analysis”.  The Orsat apparatus consists essentially of a calibrated water-jacketed gas burette connected by glass capillary tubing to two or three absorption pipettes containing chemical solutions that absorbs the gases. The absorbents are potassium hydroxide for , alkaline pyrogallol  for and ammoniacal cuprous chloride for CO measurement.

By means of rubber tubing arrangement, the gas to be analyzed is drawn into the burette and flushed through several times. Typically, 100ml is withdrawn for ease of calculation. Using the stopcocks that isolate the absorption burettes, the level of gas in the leveling bottle and the burette is adjusted to the zero point of the burette.

The gas is then passed into the caustic potash burette, left to stand for about two minutes and then withdrawn, isolating the remaining gas via the stopcock arrangements. The process is repeated to ensure full absorption. After leveling the liquid in the bottle and burette, the remaining volume of gas in the burette indicates the percentage of carbon dioxide absorbed.