The determination of linear and cyclic organic carbonates in solid media by gas chromatography

Organic carbonates of linear and cyclic structure are widely used as "green" solvents, reagents or additives in organic synthesis and polymer chemistry. Organic carbonates have found their main application as electrolytes for lithium-ion batteries. The organic carbonates do not have toxic properties, however when released into the atmosphere they undergo photooxidation forming substances harmful to the environment (carbon mono- and dioxide, formaldehyde, etc.). Methods of determination in working area air have been developed for some organic carbonates. Large-scale production and use of organic carbonates leads to pollution of air, waste and natural waters, and soils. The aim of this work is to study the methods of extracting linear and cyclic carbonates from solid media (sand, soil) with subsequent gas chromatographic determination. Head-phase extraction was used to extract linear carbonates; extraction with an organic solvent with subsequent concentration was employed in case of cyclic carbonates. The conditions for performing extraction were determined. The limits of determination were (1–2) µg/g for linear and (8‒10) µg/g for cyclic carbonates. The methods of determination are simple, rapid, and the measurement error does not exceed 10 %. Studies of the residual content of organic carbonates in soil after exposure to open air at 25 °C and 35 °C were conducted. It was established that linear carbonates are released from the soil at the highest rate. Cyclic carbonates do not pass into the gas phase; they remain in the solid matrix and undergo chemical transformation. Increasing temperature from 25 °C to 35 °C does not affect the process of decreasing the content of cyclic carbonates in soil but only affects the removal of linear carbonates.