must have the ability to extract the target analyte, (ii) must have low solubility in the aqueous phase, and (iii) must be compatible with the analytical instrumentation being used.
- In addition, it also has to satisfy some special requirements of the DLLME procedure, namely (i) to have a density greater than that of water for simple separation of the extraction phase after centrifugation, and (ii) to form a cloudy solution in the presence of the disperser solvent.
- Therefore, the number of extraction solvents available for use with the method is limited, and the choice of the extraction solvent thus becomes the method's primary drawback. Of all the requirements listed, the most restrictive is the necessity of using an extraction solvent having a density greater than that of water, since the number of organic solvents meeting this requirement is relatively small, and hazardous solvents such as halogenated hydrocarbons are used in the vast majority of them.