Amberlite® XAD

Amberlite IRA-402 Amberlite IRA-458 Amberlite IR-1180M Amberlite XAD Amberlite XAD-2 Amberlyst... 

Purifications of elfamycins have been described in the Hterature using Craig distribution (2,34), chromatography on Sephadex LH-20 (2,14,26) and Amberlite XAD-2 (10,17,19,26), supercritical fluid extraction (37), and chromatography on an Ito multilayer cod planet centrifuge (26,38). and nmr assignments of most elfamycins have been accompHshed (3,24,26,32). The characteristic uv spectra permits some differentiation (12) and bathochromic shifts associated with Al " complexation have been used to quantify efrotomycin (2, R = CH ) in feed premixes (39,40). 

Recovery and Purification. The dalbaheptides are present in both the fermentation broth and the mycelial mass, from which they can be extracted with acetone or methanol, or by raising the pH of the harvested material, eg, to a pH of 10.5—11 for A47934 (16) (44) and A41030 (41) and actaplanin (Table 2) (28). A detailed review on the isolation of dalbaheptides has been written (14). Recovery from aqueous solution is made by ion pair (avoparcin) or butanol (teicoplanin) extraction. The described isolation schemes use ion-exchange matrices such as Dowex and Amberlite IR, acidic alumina, cross-linked polymeric adsorbents such as Diaion HP and Amberlite XAD, cation-exchange dextran gel (Sephadex), and polyamides in various sequences. Reverse-phase hplc, ion-exchange, or affinity resins may be used for further purification (14,89). 

Table 8. Adsorption Capacity of Amberlite XAD-4 Polymeric Resin ...

In 200 ml of distilled water was dissolved 10.0 g of the NK631 dihydrochloride (copper-containing form). The solution was poured into a column containing 600 ml of Amberlite XAD-2 packed in distilled water. The column was washed successively with 2 liters of an aqueous solution containing 5% of EOTA-Na, 2.5 liters of a 5% aqueous sodium sulfate solution, and 630 ml of distilled water. 

Resting cell of G. candidum, as well as dried cell, has been shown to be an effective catalyst for the asymmetric reduction. Both enantiomers of secondary alcohols were prepared by reduction of the corresponding ketones with a single microbe [23]. Reduction of aromatic ketones with G. candidum IFO 5 767 afforded the corresponding (S)-alcohols in an excellent enantioselectivity when amberlite XAD-7, a hydro-phobic polymer, was added to the reaction system, and the reduction with the same microbe afforded (R)-alcohols, also in an excellent enantioselectivity, when the reaction was conducted under aerobic conditions (Figure 8.31). 

Sixteen solid-phase materials were tested on a laboratory scale and the antho-cyanin and sugar content of collected fractions were determined. Among these, reverse-phase silica gels and macroreticular non-ionic acrylic polymer adsorbents such as Serdolit PAD IV or Amberlite XAD-7 turned out to be most suitable. SPE was used to investigate these materials on an enlarged scale, improving elution gradient and column purification. Amberlite XAD-7 was successfully applied in a middle-scale separation. ... 

A sequential analysis protocol includes three steps (1) extraction in water or other appropriate solvent for the colorant, (2) purification or concentration of the colorant, and (3) separation coupled with detection of the target molecule. Different methods of extracting synthetic colorants from foods have been developed using organic solvents followed by SPE protocols using as adsorption support RP-C18, amino materials, or Amberlite XAD-2. Eor qualitative evaluations, the easiest option for separating colorant molecules from unwanted ingredients found in an extract is SPE on polyamide or wool. 

Y )- Benzyl morpholine is a potent appetite suppressant drug. The synthesis of 2-(/ )-benzyl-morpholine began with the reduction of the unsaturated bromocinnamaldehyde to the corresponding saturated (X)-bromo-alcohol by baker s yeast, with a very low ee of 63%. However, an efficient transformation can be achieved by controlling the substrate concentration with the addition of hydrophobic resin Amberlite XAD-1180 [26]. With a resin-to-substrate ratio of one and an initial substrate concentration of 5 gL, the saturated (X)-bromo-alcohol was recovered at nearly quantitative yield and 98.6% ee. 

Removal of ultraviolet absorbing organics by passage through a specific ion exchange resin such as Amberlite XAD-2. 

Mackey [854] studied the suitability of Amberlite XAD-1 resin for extracting organic complexes of copper, zinc, and iron from seawater. The results suggest... 

Dawson et al. [227] described samplers for large-volume collection of sea water samples for chlorinated hydrocarbon analyses. The samplers use the macroreticular absorbent Amberlite XAD-2. Operation of the towed fish type sampler causes minimal interruption to a ship s programme and allows a large area to be surveyed. The second type is a self-powered in situ pump which can be left unattended to extract large volumes of water at a fixed station. 

Shinohara et al. [299] have described a procedure based on gas chromatography for the determination of traces of two, three, and five-ring azarenes in seawater. The procedure is based on the concentration of the compounds on Amberlite XAD-2 resin, separation by solvent partition [300], and determination by gas chromatography-mass spectrometry with a selective ion monitor. Detection limits by the flame thermionic detector were 0.5-3.0 ng and those by gas chromatography-mass spectrometry were in the range 0.02-0.5 ng. The preferred solvent for elution from the resin was dichloromethane and the recoveries were mainly in the range 89-94%. 

Musty and Nickless [353] used Amberlite XAD-4 for the extraction and recovery of chlorinated insecticides and PCBs from water. In this method a glass column (20 x 1 cm) was packed with 2 g XAD-4 (60 - 85 mesh), and 1 litre of tap water (containing 1 part per 109 of insecticides) was passed through the column at 8 ml/min. The column was dried by drawing a stream of air through, then the insecticides were eluted with 100 ml ethyl ether-hexane (1 9). The eluate... 

Amberlite XAD-2 resin is a suitable adsorbent for polychlorinated biphenyl and chlorinated insecticides (DDT and metabolites, dieldrin) in seawater. These compounds can be suitably eluted from the resin prior to gas chromatography [356,358]. 

The insecticide fenitrothion (0,0-dimethyl-0-4-nitro-3-methylphenyl thio-phosphate) can be measured in sea water and sediments by gas chromatography, using a flame photometric detector to determine P and S [387]. The degradation products of the organophosphorus insecticides can be concentrated from large water by collection on Amberlite XAD-4 resin for subsequent analysis [383]. 

Allum and co-workers 110) studied several polymer types and focused on macroreticular, high surface area, cross-linked polystyrene. The best polymer found was AMBERLITE XAD-2, spherical beads with a high surface area of 120 m2/g. A linkage for rhodium was provided by attachment of a —CH2PPh2 group ... 

The pattern of metabolites in bile (animals only) and in urine have been investigated using column chromatography (Amberlite XAD 2 and Sephadex DEAE), tic and reversed phase HPLC in combination with radioactivity monitoring. 

The chromatographic determination of AEs in the environment has been extensively reviewed [3,4], AEs have been extracted from the aqueous matrix, among others, by solvent sublation [65], LLE [66], SPE with Amberlite XAD-2 [67], cartridges [68-73] (i.e. C1 Ci8, GCB, C8) or Cis disks [74] and matrix solid-phase dispersion for bioconcentration studies in fish samples [75],... 

A comparison of active (using pumps) and passive (relying on diffusion) sampling techniques for the determination of nitrobenzene, benzene and aniline in air was mentioned in Section IV.A77. Several LLE methods for nitroaromatic compounds dissolved in water were evaluated. High recoveries were achieved with discontinuous or continuous extraction with dichloromethane, adsorption on a 1 1 1 mixture of Amberlite XAD-2, -4 and -8 resins and elution with dichloromethane445. 

SPE with Amberlite XAD 2/4/8 mixture, elution with dichloromethane and RP-HPLC-UVD with a photodiode-array at their optimum wavelength LOD is ca 50 ng/L with 85-105% recoveries, depending on the compound445. 

Because of the advantageous dietary effects of flavonoids they have been vigorously investigated in food and food products. The objectives of these measurements were the separation and quantitation of well-known flavonoids in foods and the identification of new flavonoids. An HPLC-ESI MS method has been developed for the isolation and identification of new quercetin derivatives in the leaves of Eruca sativa (Mill). Fresh leaves (500g) were homogenized with 1 200 ml of methanol-water (7 3, v/v), the suspension was macerated for 24h at ambient temperature, then it was filtered, concentrated to 50 ml and diluted with water to 500 ml. The extract was applied to an Amberlite XAD-2 column (75 X 8cm i.d.) and was washed subsequently with 11 of water and 11 of diethyl ether. The glucoside fraction was eluted with 1.51 of methanol and the eluate was concentrated in vacuum and liophilized. 

The soluble metabolites excreted from animals dosed by injection were collected on AmberliteR XAD-4 resin, the resin eluted sequentially with diethyl ether, acetone, and methanol, and the solutes separated by thin-layer chromatography on silica gel and quantitated by liquid scintillation counting. 

Cytochrome P-450 fractions were pooled and the free Emulgen 913 removed from the enzyme preparation by stirring with Amberlite XAD-2 beads followed by filtration. The filtrate was concentrated in an Amicon ultrafiltration cell using a YM 10 Diaflo membrane. Dialysis was carried out in 2 liters of Buffer I for 24 hr when required. The fractions containing cytochrome P-450 were stored under nitrogen in 0.5 ml aliquots at -62°. 

By a quite independent method involving an Amberlite XAD-2 gel column the constant for association of [Fe(phen)3 ] " (guest) with parsley PCu(II) (host) has been determined as 1.8 x 10 at 1 = 0.01 M, with phosphate buffer at pH7.5 [120]. The high value for a 2+ ion, is accounted for by the lower ionic strength used in this study. 

Abstract A preconcentration method using Amberlite XAD-16 column for the enrichment of aluminum was proposed. The optimization process was carried out using fractional factorial design. The factors involved were pH, resin amount, reagent/metal mole ratio, elution volume and samphng flow rate. The absorbance was used as analytical response. Using the optimised experimental conditions, the proposed procedure allowed determination of aluminum with a detection limit (3o/s) of 6.1 ig L and a quantification limit (lOa/s) of 20.2 pg L, and a precision which was calculated as relative standard deviation (RSD) of 2.4% for aluminum concentration of 30 pg L . The preconcentration factor of 100 was obtained. These results demonstrated that this procedure could be applied for separation and preconcentration of aluminum in the presence of several matrix. 

Last but not least, catechols are highly water-soluble (the water solubility of catechol is approximately 1 g per 2.3 mL of water), which makes it difficult to directly extract them in situ from reaction media with organic, water immiscible solvents. Nevertheless, extraction of catechols from aqueous systems with hydro-phobic polymers such as the polystyrene-based resin Amberlite XAD-4 is... 

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