Elution Empore disk

Kicuchi and Saito used carbon Empore disks in combination with SDB-XD Em-pore disks to extract polar (methamidophos, acephate and trichlorfon) and nonpolar pesticides (diazinon, chloroneb and simazine) from water. The water sample (500 mL) was passed through the disk and the disk simultaneously eluted with 30 mL of acetone-ethyl acetate (1 1). The samples were concentrated and analyzed by GLC/MS. 

After recovering fluthiacet-methyl from the crop extract with n-hexane, acidify the residual aqueous layer and extract the free form of fluthiacet-methyl with n-hexane-ethyl acetate (2 1, v/v). After evaporating the solvent, clean up the residue with an Ci8 Empore Disk Cartridge. After methylation of the free form with trimethylsilyl-diazomethane, clean up the ester with a Bond Elut LRC SI and a Sep-Pak Plus NH2 cartridge, and quantify as fluthiacet-methyl by GC/FTD. 

Water Solid phase extraction with Empore disk. Eluted with ethyl acetate. Dried with sodium sulfate, concentrated. GC/ECD 4 ppt 86 Tomkins et al.1992... 

The extraction time applied was 20 min at 75°C and 150 atm and a flow rate of 1.5-2 mL min-1. The clean-up step consisted of a SAX Empore disk, which was simultaneously eluted and methylated by methyl iodide in acetonitrile [9]. 

A previously reviewed method was applied for OTC, TC, CTC, DXC, and DMC analysis in tissue and egg samples however, further optimization and improvement were necessary. The optimal recoveries from tissue were obtained using succinate buffer and MeOH as a depro-teinization agent. The eluate from the MCAC column was acidified and further purified on an Empore disk equipped with a poly(styrene-divinylbenzene)-RP sulphonated membrane previously activated with MeOH and hydrochloric acid (pH 1.0). The elution of TCs was done with methanolic ammonia solution. The extract was evaporated under vacuum and reconstituted in oxalic acid solution. Even though the stability of TCs is poor under alkaline conditions, no influence on the recovery was observed (59-76% with RSD < 6.5% for kidney samples) (26). 

Field, J. A. and Monohan, K. 1995. In-vial derivatization and Empore disk elution for the quantitative determination of the carboxylic acid metabolites of dacthal in groundwater. Anal. Chem.,61. 3357-3362. 

The first step is to preconcentrate and separate the material of interest from the matrix by solid-phase extraction. The solid-phase material used is hydro-phobic silica gel (octadecyltrichlorosilane derivative). After preconditioning with methanol, 0.1-1 L of sample solution is passed through the cartridge or empore disk. After rinsing with water, the adsorbed surfactant is eluted with methanol. Recovery is in the 95-100% range. In the extract, alkyl polyglycosides are determined by HPLC or GC methods identical to or comparable with those already described. 

Krueger, C. J., J. A. Field, In-vial Cjs Empore disk elution coupled with injection port derivatization for the quantitative determination of LAS by GC-FID, Anal. Chem., 1995, 67, 3363-3366. 

Filter IL of water sample through a filter paper. Place an Empore extraction disk in a Millipore extraction funnel. Rinse the disk with 10 mL of ethyl acetate, dichloromethane, and acetonitrile, successively. Dry the disk under vacuum and then rinse the disk with 10 mL of methanol and 20 mL of deionized water by vacuum filtration. Pass the prefiltered sample through the disk and elute alanycarb with two portions of 10 mL of acetonitrile. Transfer the eluates through anhydrous sodium sulfate into a 50-mL flask. Remove acetonitrile by rotary evaporation. Dissolve the residue in 1 mL of acetonitrile. 

The Empore Rad disk method allows to save time since it is no more necessary to proceed to a tedious preconcentration in routine. An acidification of water is sufficient before filtration of the sample through the membrane. The strontium fixed on the membrane is recovered by elution using a solution of 0.025 M EDTA in a basic medium. 

Examples of this approach has been reported by Janiszewski [10] and others [53] by utilizing extraction disks in a 96-well format to perform quick, automated solid-phase extractions under very simple wash and elution conditions. In one approach [10], a Tomtec Quadra 96-well workstation was used to perform the semiautomated solid-phase extraction with Empore C extraction disks. The advantage of this piece of equipment is that it allows liquid to be transferred to or from all 96-wells simultaneously, thus giving the greatest throughput advantage. 

Analogous systems are commercially available as 3 M Empore Rad Disks. These come in the form of impregnated PTEE (polytetrafluoroethylene) membranes, which are used as filters for aqueous samples (Schmitt et al. 1990). Filter dimensions constrain this type of system to carrier-free separations. These filters with the retained radionuclide may then be washed, dried, and counted directly or the radionuclide may be eluted for further processing. Current products include filters for Ra, Sr, Tc, and Cs. 

Sample preparation Grind yew needles to <3 mm in a blender. Wei out 3-4 g, add 100 mL MeOH, shake for 16 h on a wrist-action shaker, filter (Whatman 1 or 2 paper), wash the solid with 25 mL MeOH. Evaporate the filtrate to dryness under reduced pressure at 40-43°, reconstitute the residue in 10 mL MeOH and 1 mL water. Condition a 47 mm Empore SPE extraction disk (3M Corp.) with 15 mL ethyl acetate, 15 mL MeOH and 15 mL water. Use a 47 mm polypropylene separator with 10 p.m pore size (Gelman 61757) in front of the extraction disk. Pass 10 mL water and 7 mL crude extract throu the disk, wash with 15 mL water, wash with 15 mL MeOH water 20 80,15 mL MeOHrwater 45 55, elute with 20 mL MeOH. water 80 20, filter (2 p,m) the eluate, inject a 10 p,L aliquot. 

Sample preparation SPE on Empore C-18 disks eluted with dichlorometiiane or hexane. 

Sample preparation Condition a 1 mL 4 mm SDB-RPS SPE disk cartridge (3M Empore) with 500 tiL MeOH, 500 tiL air, 500 tiL water, and 1 mL air. Mix 1 mL serum with 50 tiL perchloric acid, let stand for 10 min, mix, centrifuge at 16000 g for 10 min. Add 800 tiL to the cartridge followed by 2 mL air. Wash with 800 xL 0.5% phosphoric acid in MeOH water 20 80, push through 1.5 mL air, wash with 700 xL water, push through 2 mL air, elute with 500 tiL MeOH containing 1% ammonia, push through 1.2 mL air. Evaporate the eluate to dryness under a stream of air at 70° and reconstitute the residue with 50 LL mobile phase, inject a 40 p,L aliquot. 

Sample preparation Plasma. Condition a 10 mm 6 mL SPE disk (3M Empore) with MeOH and water. Mix 1 mL plasma with 1 mL water at 0°, add 10 ng IS, add to the SPE disk, wash with MeOHiwater 15 85, elute with MeOH water trifluoroacetic acid 95 5 3. Evaporate the eluate to dr3Uiess under reduced pressure at 45°, reconstitute the residue with 150 (xL 100 mM ammonium acetate, inject a 125 p,L aliquot. Urine. Condition a 1 mL Bakerbond carboxylic acid SPE cartridge with MeOH and water. Mix 1 mL urine with 1 mL water, add 100 ng IS, vortex, add to the SPE cartridge, wash with 1 mL water, wash with 1 mL MeOH water 50 50, elute with MeOH water trifluoroacetic acid 95 5 3. Evaporate the eluate to dr3mess under reduced pressure at 45°, reconstitute the residue with 150 p,L 100 mM ammonium acetate, inject a 60 xL aliquot. 

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