Volatilization separates a desired component, known as an analyte, from the other compounds in a sample by converting it to a volatile species through processes like controlled heating or chemical reactions. Removing the volatile species changes the weight of the sample. So, measuring the difference in the sample's weight before and after volatilization gives the amount of the analyte in the original sample, provided no other constituents are volatilized in the process. Alternatively, the analyte can be treated with a chemical reagent in a closed vessel to transform it into a chemically different volatile species. The volatilized substance is then completely removed from the reaction mixture by heating the solution or bubbling a gas through the mixture. Then, it is selectively absorbed in a pre-weighed trap containing an appropriate absorbent. The weight difference between the trap before and after volatilization indicates the amount of volatile substance released from the sample, which is stoichiometrically related to the amount of the analyte in the sample.