Recently, a new microextraction method was developed, which is DLLME integrated with the solidification of a floating organic drop (DLLME-SFO) In DLLME-SFO, the extraction solvent after DLLME, was collected in the top of the test tube and was then cooled by inserting it into an ice bath for 5 min. The solidified extraction solvent was transferred into a suitable vial and immediately melted at room temperature; then it was finally injected into
a suitable instrument. DLLME-SFO is widely applied to the preparation of environmental samples and rarely applied to the analysis of drugs in complex biological fluids