SUPERCRITICAL FLUID EXTRACTION OF POLAR ANALYTES USING INSITU CHEMICAL DERIVATIZATION

Analytical-scale supercritical fluid extraction (SFE) of polar organics from solid samples was enhanced by derivatizing the analytes to less polar species under static SFE conditions using reagents including trimethylphenylammonium hydroxide and boron trifluoride in methanol. After derivatization, the analytes were extracted with CO2 using standard SFE techniques and analyzed without additional treatment using conventional capillary GC. Total time for derivatization and extraction can be < 30 min; however some samples which contained high concentrations of reactive matrix components required multiple derivatization/extraction steps to achieve quantitative recoveries. The development and application of derivatization/SFE methods for the quantitative (> 90%) derivatization and extraction recoveries of native and spiked acid herbicides ((2,4-dichlorophenoxy)acetic acid and Dicamba) from soil and sediment, microbial phospholipid fatty acids (as their methyl esters) from whole cells, and wastewater phenolics (as their methyl ethers) from water and from C18 sorbent disks is presented.