Pressurized hot water extraction PHWE

Application of pressurized hot water (subcritical water) as the extraction medium Extraction of moderately and nonvolatile, thermally stable organic pollutants from a variety of solid and semisolid environmental matrices Extraction of metals such as copper and lead from spent industrial oils with acidified pressurized hot water extraction (PHWE) 76-78,79... 

In pressurized liquid extraction (PLE), rapid extraction is performed with small volumes of conventional solvents by using high temperatures (up to 200°C) and high pressures (up to 20 000 kPa) to maintain the solvent in a liquid state. The extraction can also be done with a purely aqueous phase, a technique often referred to as pressurized hot water extraction (PHWE) or subcritical water extraction. Temperatures of up to 325 C have been used in PHWE 29-38). 

Pressurized hot water extraction (PHWE) has also been used for the analysis of several brominated analytes in sediment. The extracted analytes were trapped into a solid-phase trap (Tenax TA), from which these were eluted with pentane ethyl acetate mixture after drying the trap with nitrogen. No further cleanup of the extract was required. Best results were obtained at 325°C, using a pressure of 118 bar and an extraction time of 40 min. Compared with Soxhlet extraction, extraction yields were clearly better, and the extract was much cleaner. 

Pressurized liquid extraction (PLE) is also known as pressurized solvent extraction (PSE), enhanced solvent extraction (ESE), pressurized fluid extraction (PEE), or accelerated solvent extraction (ASE ) in the literature. PLE is considered an environmentally friendly extraction technique because it requires only small volumes of solvents. PLE was primarily used for the extraction of environmental samples, such as soils and sediments. Elevated temperatures (usually between 50 and 200 °C) and pressures (between 10 and 15 MPa) are used in closed vessels, which allow extractions to be completed in a very short time. High pressure allows the solvent to remain in its liquid state even at temperatures above its boiling point, and forces it into the matrix pores. High temperatures decrease the solvent viscosity and increase metabolite solubilization, the diffusion rate, and mass transfer kinetics, thus facilitating desorption of the analytes from the plant material. Most PLE applications reported in the literature employ the same organic solvents as those commonly used in conventional solid-liquid extraction techniques. When water is used as the extraction solvent, the technique is referred to as pressurized hot water extraction (PHWE). Extractions are carried out in stainless steel extraction cells of various volumes (typically 1-250 mL). One extraction cycle is generally applied for 5-20 min at temperatures ranging from 50 to 140 °C in the vast majority of applications. 

On-Line Systems Flowing MMLLE systems have been established in different layouts with automation and on-line hyphenation to GC and HPLC analysis. An automated on-line FS-MMLLE-GC system with a loop-type interface compatible with LVI was used for the extraction of pesticides and PAHs in surface waters.86 In another study, pressurized hot water extraction (PH WE) was coupled on-line to a FS-MMLLE-GC-FID system and applied to the analysis of PAHs in soil, where MMLLE was used as a cleanup and concentration step of the PH WE extract prior to final GC analysis.87 In addition, an HF-MMLLE setup was incorporated in PHWE and GC, resulting in an online PHWE-HF-MMLLE-GC system, where the HF membrane module contained 10-100 HFs. The system served for the extraction and analysis of PAHs in soil and sediments ... 

Other PHWE, pressurized hot water extraction SFE, supercritical fluid extraction TBA, tetrabutylammonium hydroxide. 

DBTHS, disodium 5,13-his(dodecyloxymethyl-4,7.11,14-tetraoxa-l,17-heptadecanedisulfonate ITP, isotachophoresis m-HEC, methyl-hydroxyethylcellulose PVP, polyvinylpirrolidone PSDVB, polystyrene-divinylbenzene copolymer SB-P-CD, sulfobutylether-p-cyclodextrin CAR-PDMS, carboxen-polyfdimefhylsiloxane) ESI-IT-MS, electrospray ionization ion trap-mass spectrometry CHES, 2-(V-cyclohexylamino)-ethanesulphonic acid CAPS, 3-(cyclohexylamino)-l-propanesttlfonic acid PHWE, pressurized hot water extraction ICP-MS, inductively coupled plasma-mass spectrometry SPME, solid-phase microextraction SPE, solid-phase extraction. 

TTAOH, tetradecyltrimethylammonium hydroxide ESI-IT-MS, electrospray ionization ion trap mass spectrometry SB- -CD, sulfobutylether-p-cyclodextrin PHWE, pressurized hot water extraction FPD, flame photometric detector SPE, solid-phase extraction MES, 2-[morphine]ethanesulphonic acid DDAOH, didodecyldimethylammonium hydroxide. 

Acronyms d SPE dispersive solid-phase extraction HILIC hydrophilic interaction liquid chromatography IT ion trap LLE liquid—liquid extraction MSPD matrix solid-phase dispersion PGC porous graphitized carbon PLE pressurized-liquid extraction PHWE pressurized hot-water extraction QqQ triple quadrupole QLIT quadrupole linear ion trap QuEChERS quick, easy, cheap, effective, rugged, and safe TCA trichloroacetic acid UHPLC ultraperformance liquid chromatography ZIC ttILIC zwitterionic hydrophilic-interaction liquid chromatography. 

LLE, liquid-liquid extraction LSE, liquid-solid extraction MAE, microwave-assisted extraction PHWE, presurized hot water extraction PEE, pressurized liquid extraction SAE, sonication-assisted extraction SEE, supercritical fluid extraction SPE, solid-phase extraction SPME, solid-phase micro extraction. 

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