Octanol/water partition coefficient determination by VALLME

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In most of the applications, microextraction techniques are employed to isolate and/or enrich target analytes from a given sample in order to make easier (more selective and sensitive) their final determination by an appropriate instrumental technique. However, the versatility of these techniques allows their use in the determination of chemical constants. Researchers from the University of Alicante at Spain have developed a vortex assisted liquid-liquid microextraction (VALLME) procedure to determine the octanol-water partition coefficient (Kow) in a simple way. Kow is an important parameter that can be used for different purposes like the studies of the bioaccumulation rates of toxicants since Kow is similar to the lipid-water partition coefficient or the proper selection of an extractant in a extraction technique since Kow provides information about the polarity of a compound.

In brief, the proposed VALLME procedure consist on the addition of 50 µL of 1-octanol to 10 mL of an aqueous solution of the compound under study. After a simple vortex assisted agitation and centrifugation steps, a extract of 1-octanol with the target compound is obtained and analyzed by HPLC.

The proposed method presents several advantages. The obtained values of Kow are very good correlated with the reported values in the literature. This aspect is clearly shown in the Figure where the Kow obtained by VALLME for six different compounds (namely: hydroquinone; dichlorvos; simazine; 2,6 dichlorophenol; 2,4 dichlorophenol and naphthalene) are compared with the reported values. The six compounds cover a wide range of polarities which indicates the validity of the method. Moreover the method is faster than its counterparts.


We strongly recommend this article to our readers. In the original manuscript you will find interesting information about the extraction time profiles of the different compounds, the comparison with other accepted methods and the way to calculate the Kow.

Reference:

(1) Rapid determination of octanol–water partition coefficient using vortex-assisted liquid–liquid microextraction. Link

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