Macroreticular resin

Air Collect on XAD-4 macroreticular resin extract with ethyl acetate GC/NPD 0.2 ng/m 85-111 Seiberet al. 1989... 

Water (run-off) Collect on XAD-2 macroreticular resin extract with diethyl ether HPLC/UV 2-3 pg/L 99.75 vi Paschal et al. 1977 > > —... 

Le Bel GL, Williams DT, Griffith G, et al. 1979. Isolation and concentration of organophosphorus pesticides from drinking water at the ng/L level, using macroreticular resin. J AOAC 62 241-249. 

CFPs are normally manufactured as submillimetric beads or powders (Figure 2) [15]. A convenient simplified comparison between the micrometer and nanometer scale morphology of gel-type and macroreticular resins is illustrated in Figure 3. 

Figure 3. Schematic representation of the micro- and nanoscale morphology of gel-type (a) and macroreticular (b) resins [13], Level 1 is the representation of the dry materials. Level 2 is the representation of the microporous swollen materials at the same linear scale swelling involves the whole polymeric mass in the gel-type resin (2a) and the macropore walls in the macroreticular resin (2b). The morphology of the swollen polymer mass is similar in both gel-type and macroreticular resins (3a,b). Nanopores are actually formed by the void space surrounding the polymeric chains, as shown in level 4, and are a few nanometer wide. (Reprinted from Ref [12], 2003, with permission from Elsevier.)...

This argument is confirmed by the study of CO pulse chemisorption by Biffis at al., mentioned above. In this piece of investigation, the authors prepared a 2% (w/w) palladium catalyst supported by Lewatit UCP 118, a macroreticular resin (nominal cld = 18 %) from Bayer. Its TEM characterization showed a remarkably heterogeneous distribution of the metal nanoclusters, which are apparently located close to the surface of the polymer nodules [62] (Figure 9). 

Figure 9. Distribution of palladium nanoclusters in a M°/CFP catalyst based on the macroreticular resin Lewatit UCP 118. (Reprinted from Ref [62], 2000, with permission from Elsevier.)...

LeBel GL, Williams DT, Benoit FM. 1981. Gas chromatographic determination of tnalkyl/aryl phosphates in drinking water following isolation using macroreticular resin. J Assoc Off Anal Chem... 

Macroreticular resins have also been used for the collection of trace organics. 

Osterroht [40,41] studied the retention of non-polar organics from seawater onto macroreticular resins. 

Picer and Picer [357] evaluated the application ofXAD-2, XAD-4, and Tenax macroreticular resins for concentrations of chlorinated insecticides and polychlorinated biphenyls in seawater prior to analysis by electron capture gas chromatography. The solvents that were used eluted not only the chlorinated hydrocarbons of interest but also other electron capture sensitive materials, so that eluates had to be purified. The eluates from the Tenax column were combined and the non-polar phase was separated from the polar phase in a glass separating funnel. Then the polar phase was extracted twice with n-pentane. The -pentane extract was dried over anhydrous sodium sulfate, concentrated to 1 ml and cleaned on an alumina column using a modification of the method described by Holden and Marsden. The eluates were placed on a silica gel column for the separation of PCBs from DDT, its metabolites, and dieldrin using a procedure described by Snyder and Reinert [359] and Picer and Abel [360]. 

Cotterill [222] has developed a procedure, discussed below, in which the herbicides are extracted from soil with saturated calcium hydroxide solution. After clean-up the residues are ethylated using iodoethane and tetrabutylammonium hydrogen sulphate as counter ion. Liquid-liquid partition and the use of a macroreticular resin column were compared as clean-up steps and the reaction conditions for optimum yield of ethyl ester were evaluated. 

All of the methods discussed above use liquid-liquid partition for cleanup. However, Smith and Hayden [231] and Johnson etal. [232] have shown that the macroreticular resin XAD-2 is an efficient adsorber of 2,4-D. 

Combined synthesis/analysis operations were performed to characterize the MIMs and identify the impurities. The principal impurities were synthesized and isolated using HPLC. The intermediates and final products were purified on macroreticular resins. 

Richard JJ, Junk GA. 1986. Determination of munitions in water using macroreticular resins. Anal Chem 58 723-725. 

Amberlyst 15 ion-exchange resin is a strongly acidic, macroreticular resin purchased from Aldrich Chemical Company, Inc. The reaction fails in the absence of the acid catalysts. 

TCA extn, macroreticular resin (Diaion HP-20) column cleanup, aqueous MeOH elution, evapn, and reconstitution in H2O/MeOH (2 1)... 

Adsorbents. The macroreticular resins XAD-2 and XAD-4 were separately suspended in distilled water, and the suspensions were stirred to leave the fine particulates floating. These fines were removed by decantation of the supernatant layer. This operation was repeated until no opalescence was noticeable in the supernatant layer. After filtration through Whatman no. 1 filter paper and washing with methanol, the resins were dried at 70 °C in a convection oven prior to further purification. The average weight per milliliter of the resin was found to be 0.40 0.02 g. 

XAD-2 macroreticular resin columns. This situation implied that the XAD-2 column was not effective in retaining completely all the solutes present in the water samples. [NOTE The XAD-2 resin column contained about 25% more packing, and the rate of percolation was about the same as that normally used for processing 200 L of tap water (21).] In addition, a variety of volatiles that appeared immediately following the solvent peak were also present. Subsequent analysis of these concentrates by GC-MS indicated the presence of 6-chloro-2,4-diamino-1,3,5-triazine (tentative), 2,5-diphenylisoxazole (tentative), tributoxyethyl phosphate (confirmed), bis(2-ethylhexyl) phthalate (confirmed), and dimethylbenzoic acid (confirmed) from site 1. The concentrate from site 2, however, showed the presence of 2,4,5-trichlorophenol (confirmed), BHC (confirmed), 2,5-diphenylisoxazole (tentative), bis(2-ethyl-hexyl) phthalate (confirmed), trimethylbenzene (confirmed), ethylbenz-aldehyde (confirmed), ethylacetophenone (confirmed), hexanoic acid (confirmed), and 4-cyano-3,7,ll-tridecatriene (tentative). 

XAD-2 and XAD-4 macroreticular resin adsorbents were found to be adequate to accumulate the organic pollutants considered in the present study except for bis(2-ethylhexyl) phthalate. Polyurethane-carbon ad-... 

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