Centrifugeless dispersive liquid-liquid microextraction based on salting-out phenomenon as an efficient method for determination of phenolic compounds in environmental samples

Abstract

A new centrifugeless dispersive liquid-liquid microextraction (DLLME) method was applied for the convenient extraction of some phenolic compounds from environmental samples. After dispersing the extracting solvent into the sample solution (10.0 mL), the mixture was passed through a small column filled with 5 g sodium chloride. As a result, phase separation was achieved via the salting-out phenomenon, and the extracting solvent was suspended on top of the sample solution. Using a low-toxic and solidifiable extracting solvent (1-dodecanol), after immersing the column into an ice bath, the extracting solvent was solidified, collected easily, and injected into an HPLC-UV instrument. The overall extraction time was 7 min, consumption of the extracting solvent was efficiently reduced to 50 μL, and the centrifugation step was simply eliminated, which made the automation of the procedure easier than the normal DLLME technique. A series of parameters influencing the extraction were investigated systematically. The optimal experimental conditions were found to be 50 μL of 1-dodecanol as the extracting solvent, a flow rate of 2.0 mL min, and a pH value of 4.0 for the sample solution. Under these conditions, the method provided a good linearity in the range of 0.5-800 ng mL, low limits of detection (0.1-0.3 ng mL), good extraction repeatabilities (RSDs below 9.1%, n = 5), and enrichment factors of 100-160. Graphical Abstract Schematic diagram of the centrifugeless dispersive liquid-liquid microextraction.

Critical evaluation of microextraction pretreatment techniques—Part 2: Membrane‐supported and homogenous phase based techniques

“…The method has all the advantages and disadvantages of SDME or solid drop liquid phase microextraction with the exception of the requirement to stir the sample solution (but this is possible) and the extraction is more rapid because of solution dispersion [90,91]. Mirparizi et al [92] used the salting-out effect instead of centrifugation for separation of the extraction solvent layer. 1-Dodecanol was mixed with the sample solution, fine droplets were created and the extraction was carried out.…”

“…Mirparizi et al. used the salting‐out effect instead of centrifugation for separation of the extraction solvent layer. 1‐Dodecanol was mixed with the sample solution, fine droplets were created and the extraction was carried out.…”

Liquid phase microextraction techniques combined with chromatography analysis: a review

“…Centrifugeless modes of DLLME were reported [86][87][88]. Additional modifications to DLLME methods include the use of a solvent, which causes phase separation of the emulsion [89].…”

Screening of Parabens in Natural Water by Salting-out Based Centrifugeless Dispersive Liquid-liquid Microextraction Combined with HPLC-UV

“…The microextraction procedure has been introduced in detail 28 and presented as a schematic diagram in Fig. 1.…”

“…26,27 Recently, Rajabi et al has published a novel salting-out based centrifugeless DLLME method for the determination of some analytes in several matrices. 28,29 Herein, an organic solvent whose melting point is near the room temperature is dispersed into the sample solution to facilitate the extraction process. Then, by passing the mixture through a test tube filled with a certain amount of sodium chloride, the phase separation is easily achieved.…”