Disks Empore

One field study on the mass flow of secondary alkanesulfonates was conducted in the Zurich-Glatt municipal wastewater treatment plant [37]. The concentration of alkanesulfonates in samples of raw sewage and primary and secondary effluents was analyzed using the above-described SPE with C18 Empore disks and injection port derivatization with GC-MS detection. The con-... 

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. 

Verbruggen et al. [20] PCMs (AHTN and HHCB) Wastewater effluent The Netherlands - Biomimetic and exhaustive extraction - C18 Empore disks - GC-MS - Recovery >95% detection limit=0.1 ng/L... 

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). 

Particle-loaded membrane extraction disks, the so-called Empore disks, form an alternative to SPE cartridges [27, 78-79]. With Empore disks, higher sampling flow-rates are possible. They show excellent sorbent capacity. Recoveries at 0.1-pg/l level... 

On-line SPE via valve-switching techniques, pioneered by the group of Brinkman [80], is frequently used in the enviroiunental analysis of aqueous samples, as it enables the rapid treatment of large samples. The precolumn enables selective sorption of the analytes, removal of hydrophihc interferences, and significant analyte preconcentration. In most cases, either 1-10 mm x 2-4.6 mm ID SPE cartridges packed with 30-50 pm ID particles are used. Typical applications of on-hne SPE-LC-MS are the determination of acidic herbicides [41], sidfonylureas [49], and organophosphorous pesticides [30]. Instead of SPE cartridges, Empore disks can be used on-line as well [79]. 

D. Barcel6, S. Chiron, S. Lacorte, E. Martinez, J.S. Salau, M.C. Hennion, Solid-phase sample preparation and stability of pesticides in water using Empore disks. Trends Anal. Chem., 13 (1994) 352. 

Off-hne solid-phase extraction (SPE) procednres, based on cartridges, Empore disks, or ZipTip procednres, are freqnently apphed for clean-np of peptide mixtures prior to ESI-MS or LC-MS analysis. This was evalnated by Erdjnment-Bromageeia/. [23]. 

A 2000-fold increase in concentration was achieved for traces of the mutagenic HAA PBTA-1 (32a) and PBTA-2 (32b) in 0.5 L samples of polluted river water by SPE on an Empore disk (C18) after drying the disk it was extracted with 5 mL of MeOH, the solution was evaporated to 0.25 mL and 2.5 ng of diazinon-d 0 (73) was added as internal standard. Quantitative recoveries were observed for both pollutants from spiked river water at 5 to 10 ngL 1 levels. Aliquots of 10 p,L were analyzed by HPLC-MS (Section IV.B.1)95. 

The trace enrichment of pesticides from groundwater is a straightforward problem for reversed-phase SPE. The following example uses the EMPORE disk (C-18) to isolate organochlorine pesticides including aldrin, chlordane, endrin, heptachlor, lindane, methoxychlor, pentachlorophenol, and toxaphene from groundwater (Fig. 4.15). 

Strong anion exchange quaternary amine (N ) Empore Disk (3 M)... 

The ion-exchange disks are available from a number of manufacturers (Table 6.1 and Appendix Product Guide). The disks typically have from 0.2 to 0.4 meq/disk (47 mm) exchange capacity. The disks manufactured by 3 M (Empore disks) are made from a styrene-divinylbenzene copolymer therefore, they do not have the problem of the silica-based disks with limited pH range. The Empore disks also come in a chelation disk for the removal of trace metals from solution, as well as in strong anion-exchange form (Fig. 6.1). 

Empore disk extraction. The major cations, calcium, sodium, magnesium, and... 

Empore disk, -500 mg of strong cation exchange resin,... 

Empore disk, 500 mg of strong cation exchange resin, form, pre-condition with 10 mLeach of acetone and DI water, condition with 10 mL of 20% HNO3, then 2x10 mL DI water. 

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. 

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