Why liquid membrane extraction is an attractive alternative in sample preparation

Abstract

The use of liquid membrane-based extractions is increasingly seen as offering an alternative to conventional sample preparation procedures in analysis of chemical species in both environmental and biological media. In this article, emphasis is placed on the attractiveness of liquid membrane-based extraction techniques to a variety of analytical applications such as speciation of metal ions in biological fluids, time-weighted average field sampling, and time-weighted average passive field sampling. Further, the area of designing new and much simpler miniaturized configurations, which is enjoying much attention in liquid membrane-based extraction techniques, is discussed.

Influence of temperature on mass transfer in an incomplete trapping single hollow fibre supported liquid membrane extraction of triazole fungicides

“…SLM extraction technique can offer high masstransfer rates and the possibility for a wide variety of organic liquids and additives without compromising the stability of the membranes. The technique has been used for sample preparation in a number of applications as cited in several review papers [5,6]. Typically, the uncharged analytes are extracted from the flowing aqueous donor stream into the organic phase followed by a second extraction into the acceptor phase, which is usually stagnant.…”

Hollow‐fibre supported liquid membrane extraction for determination of fluoxetine and norfluoxetine concentration at ultra trace level in sewage samples

“…Charged compound will not diffuse through a non-charged organic solvent and, thus, will not be extracted. It is recommended that the pH of the donor is at least two units above the pK a value for basic compounds [27]. Consequently two different donor (sample) solutions were tested, one adjusted to pH 12.5 with sodium hydroxide and the other to pH 12.2 by 0.05 M phosphate buffer.…”

“…The use of undecane reduces the flux through the membrane, thus reducing the enrichment factor to half for fluoxetine and 80% for norfluoxetine. Undecane is less soluble in water and it has been cited [27,29] to be more stable in the pores, leading to good long-term performance. However, when this solvent was used, a poorer reproducibility (higher RSD values) was observed.…”

Extraction of Lead through Supported Liquid Membrane Using Triethanolamine/Cyclohexanone Carrier and Na2SO4strippant

“…In this technique an organic liquid is immobilized in micro porous membrane that is placed between two solutions. At the boundary of the feed solution and the membrane, the solute is moved to the membrane liquid; which then moves by itself in a forming a complex to the farther side of the SLM, i.e the strippant (Chimuka et al,2004). Membrane separation technology involves separation of organic, inorganic and suspended matters, which are often present simultaneously and is used in many industries like metal plating industry, micro-electronics industry, pharmaceutical industries and food and beverages industries to provide high quality products.…”