What Is the Difference Between Liquid Liquid Extraction and Supported Liquid Extraction?

What Is Liquid Liquid Extraction?

Liquid-liquid extraction (LLE) is a labor-intensive technique used to separate compounds into two immiscible liquids: an aqueous layer and an organic solvent layer. The process involves extensive sample mixing, after which the solutes are partitioned between the aqueous and organic phases. Centrifugation may be needed to break up emulsions. Typically, organic compounds favor the organic layer, while salts tend to remain in the aqueous layer. LLE can be challenging and cumbersome to automate. While LLE is a reliable method for sample preparation in drug of abuse urine analysis, it is also time-consuming and requires considerable manual effort.

What Is Traditional Supported Liquid Extraction?

In traditional supported liquid extraction (SLE), an aqueous sample is loaded onto the sorbent bed containing diatomaceous earth (DE), where the aqueous sample is coated as a thin film on the material. A water-immiscible solvent is then passed through the SLE bed, extracting target analytes from the sample and eluting them into a collection tube for post‑treatment and analysis. Compared to traditional LLE, the interaction surface between aqueous and organic phases using SLE is significantly increased, which improves analyte partition from the aqueous to organic phase and obsoletes the mixing step. This provides significant time and labor savings over conventional LLE with simplified and improved reproducibility.

Advantages of Supported Liquid Extraction With Synthetic Media

SLE with diatomaceous earth is a natural material, consisting of irregular fossilized microorganisms, and it is difficult to control the sorbent batch‑to-batch particle consistency. The sorbent variability complicates product manufacturing and quality control and leads to product performance inconsistency. SLE with diatomaceous earth can give lower and inconsistent water-holding capacity when compared to synthetic media. The Chem Elut S (SLE with synthetic media) sorbent greatly improves water-holding capacity, batch‑to-batch consistency, and performance consistency. The 96-well plate design offers large headspace for samples and eluent, a square upper frit that holds sample until pressure is applied, a full skirt for hardware compatibility, and fast, consistent elution. Elute your analytes of interest into a Chrom Tech 96 Well microplate for analysis with your LCMS system.

Conclusion

Simplify your liquid liquid extraction workflow by using supported liquid extraction with the Agilent Chem Elut S SLE products. They deliver reliable, reproducible results with minimal method development and a walk-away-workflow. Chem Elut S will improve reproducibility by minimizing analyst-to-analyst variability and eliminate emulsions because shaking is eliminated.