Application of deep eutectic solvents in analytical chemistry. A review

Developments in single-drop microextraction.

Sample preparation techniques for the determination of trace residues and contaminants in foods.

Green aspects, developments and perspectives of liquid phase microextraction techniques.

Greening extraction techniques to improve the sensitivity and the selectivity of analytical methods is the sustainable alternative to classical sample-preparation procedures used in the past In this update, we review the main strategies employed in the scientific literature to reduce deleterious side-effects of extraction techniques We demonstrate that the evolution of sample-treatment procedures is focused on the simultaneous improvement of the main analytical features of the method and its practical aspects, including the economic case

The role of green extraction techniques in Green Analytical Chemistry

Single drop microextraction--development, applications and future trends.

Since its inception in 1995, solvent-microextraction (SME) techniques for sample preparation have grown increasingly popular due to their simplicity, low cost, and adaptability to a wide variety of sample types and analytes. SME methods are used alone or as final clean-up and concentration techniques in preparing environmental, clinical, forensic, personal-care, pharmaceutical and food-product samples. There are two broad categories of SME: exposed-solvent and membrane-protected solvent techniques. The principal exposed-drop techniques include single-drop microextraction (SDME), headspace single-drop microextraction (HS-SDME), liquid-liquid microextraction (LLME), liquid-liquid-liquid microextraction (LLLME) and dispersive liquid-liquid microextraction (DLLME). The principal membrane-protected modes are hollow-fiber-protected 2-phase microextraction [HF(2)ME] and hollow-fiber-protected 3-phase microextraction [HF(3)ME]. In recent years, interest in SME has increasingly turned to refinements of these modes for use in practical sample preparations. This has involved innovations (e.g., ionic liquids, ultrasonic-assisted emulsification, automation, and low-density solvents for DLLME). In this review, we explore these and other SME innovations appearing in the literature in the period from mid-2010 to mid-2012.

Advances in solvent-microextraction techniques

Analytical characteristics of the determination of benzene, toluene, ethylbenzene and xylenes in water by headspace solvent microextraction.

Single-drop microextraction (SDME) was the first successful application of the solvent-microextraction (SME) technique for concentration and purification of analytes from aqueous and gaseous samples. However, SDME has inherent extraction-solvent-volume and drop-stability limitations, leading to the development of other SME techniques. SDME and related exposed solvent techniques remain popular due to their low cost, simplicity and the need for only common laboratory equipment. Many of these techniques also lend themselves to complete automation and on-line continuous-flow analysis. Since SDME and its related techniques involve the use of microliter quantities of extraction solvent, they are important green analytical methods. Recent uses of SDME and related techniques in green analytical methods are: direct immersion SDME (DI-SDME), headspace SDME (HS-SDME), drop-to-drop microextraction, (DDME), directly-suspended droplet microextraction (DSDME), liquid-liquid-liquid microextraction (LLLME), continuous-flow microextraction (CFME), and solvent-supported microextraction (SSME).

Recent trends in using single-drop microextraction and related techniques in green analytical methods

Liquid phase microextraction (LPME) has become an increasingly important tool for environmental, pharmaceutical, food, clinical and industrial analysis laboratories. LPME (also referred to as solvent microextraction, SME) consists of three major micro solvent extraction modes, single drop microextraction (SDME), hollow fiber-liquid phase microextraction (HF-LPME) and dispersive liquid-liquid microextraction (DLLME), each of which has unique extraction solvent requirements. LPME, with greatly reduced solvent requirements compared to traditional extraction and purification techniques, fulfills the requirements for classification as a green analytical chemistry (GAC) procedure. However, this designation also requires appropriate selections of extraction solvents and appropriate waste recycling and disposal to be fully classified as green. This review addresses the GAC solvent requirements for LPME modes, in part based on published industrial and analytical solvent selection guides (SSGs).

John M. Kokosa

Papers

Single drop microextraction--development, applications and future trends.

Advances in solvent-microextraction techniques

Analytical characteristics of the determination of benzene, toluene, ethylbenzene and xylenes in water by headspace solvent microextraction.

Recent trends in using single-drop microextraction and related techniques in green analytical methods

Selecting an extraction solvent for a greener liquid phase microextraction (LPME) mode-based analytical method