Polyamide powder

Polyamide powder showed to be highest recovery adsorbent for quantitative determination, compared to other resins. The isolated colorants were analyzed by... 

Acrylonitrile and other olefinic monomers can be grafted on polycaprolactam by an indirect method in which the polyamide powder is first submitted to nitro-sation with dinitrogen trioxide and then bulk polymerized at 60° C (12). 

Different resins have been used to clean up or prefractionate anthocyanins prior to isolation or characterization, including ion-ex-change resins, polyamide powders, and gel materials. Chromatography on Dowex or Amber-lite ion-exchange resins, as well as polyamide powders such as polyvinylpyrrolidone (PVP), have been used to isolate polar nonphenolic compounds from crude anthocyanin extracts. Column chromatography on Sephadex LH-20 can be used for fractionation of crude extracts and is also particularly useful for purification... 

Food samples are dissolved in water and acidified with acetic acid (135,157). According to Gilhooley et al. (157), excess methanol has to be removed from solutions before passing through polyamide because it impairs the adsorption of the dyes by the polyamide. The solution is stirred with polyamide powder, and the slurry is transferred to a microcolumn or it is passed through the column of polyamide. The latter is recommended since dyes are adsorbed as a narrow band at the top of the column. The column is washed with hot water to remove sugars, acids, and flavoring materials and with acetone to remove basic dyes, water-soluble carotenoids, and some antho-cyanins. The adsorbed acid dyes are eluted with methanol sodium hydroxide (164,172,175), with methanol ammonia (176), or with acetone ammonia (157). Acetone ammonia is preferred because it can be removed in a water bath and, on addition of acid, no salts are formed that interfere with the adsorption of the dyes by the polyamide (157). The eluate is evaporated to dryness and redissolved in the HPLC mobile phase (156). 

Analytical Use of Fluorescence-Producing Reactions of Lipid- and Carbohydrate-Derived Carbonyl Groups with Amine End Groups of Polyamide Powder... 

Chemical Characteristics of the Oxidative Fluorescence-Producing Reaction and Presumptive Implication of Malonaldehyde The reaction producing measurable fluorescence on polyamide powder can be carried out in the gas phase by exposure to the volatiles from oxidizing polyunsaturated lipids, whether acids, esters, triglycerides, or phosphatides. It can be also carried out within either the oil phase or a water emulsion, and, as noted above, it can be followed in the vapor above an emulsion, providing the pH is 5.5 or below. 

Weist, J.L., Karel, M. 1992. Development of a fluorescence sensor to monitor lipid oxidation. 1. Fluorescence spectra of chitosan powder and polyamide powder after exposure to volatile lipid oxidation products. J. Agric. Food Chem. 40, 1158-1162. 

A total of 5g polyamide powder (trade quality) is added to the extract and thoroughly mixed, and the mixture is filled in a glass column (diameter, 1 cm length, 15 cm) and eluted in three steps ... 

Polyamide powder Anthocyanins [42], aromatic acids [42], antioxidants [43], flavanoids [44], proteins [45]... 

To tackle the problem of fuel loss through the tank walls, polar barrier layers were tested. Among the methods tried were fluorination and sulfonation, as well as epoxy resin or polyamide powder coatings on the fuel tank walls. Again, cost and process safety were the issues begging for solutions, and fluorination and sulfonation proved to be the processes of choice for enhancing barrier properties. Both inline and offline processing approaches were tested, and fluorination with fluorine... 

Ot asol, Fine particle-size polyamide powders. Elf Atochem North America, Inc. 

Phenolic antioxidants Polyamide powder Methanol - water (3 2) or methanol - carbon tetrachloride (1 9) Diazotised sulfanilic acid [13]... 

Phenolic-Epoxy Phenolic-polyamide powder Film, liquid Two-part liquid liq./powder 3 Mo./0°C Indefinite 30/ 30-120" 3 95/ 165" 220 1/ 7-40" 7-70 1600-2200 1-2 -60-260 -60-150... 

Polyamide powder for TLC is prepared by dissolving commercial Perlon powder, e. g., Ultramid BM 2 K 228 (Firm 16) in 35% hydrochloric acid and precipitating it with methanol/water, 1 1, stirring energetically. The precipitate s filtered off and dried. 10 g powder are sn nded in 100 ml methanol for coating five 20 X 20 cm plates. 

Some authors have used cellulose [103] or alumina layers [60] (Table 88, VII), partly in mixtures with silica gel [19], in order to separate basic and neutral substances. Indole derivatives on alumina- and especially on cellulose layers, generally tend to tail-formation. Benassi et al. [2] have accomplished good separations of urine metabolites on 100 (xm thick polyamide layers. The completely smooth layers prepared with polyamide powder DF (Firm 118), fluorescing in UV254, yield sharply defined zones they are, however, very sensitive to rubbing so that there are limits to midtiple application of an extract [46] (Table 88, XII). 

It has become apparent that, in addition to the known disadvantages of loosely spread layers, the solvents quoted [71, 82] cannot necessarily be used without difficulty. The possibilities of separating numerous dyes, using TLC, have been subsequently investigated. Along with siUca gel G and alumina G and H (Firm 88), 1 1 mixtures of both, MN-cellulose powder, acetylated MN-cellulose powder (Ac) (Firm 83) and polyamide powder (Firm 153) have proved useful in thin-layer chromatographic separation. 

Mixtures of basic dyes may be separated by column chromatography on polyamide powder, usiug water or ethanol-water (80 + 20) or (60 + 30) as solvents [71]. Separations are possible by PC on impregnated paper [6, 18] or acetyl-paper [70]. TLC separations are advantageously shorter than these PC procedures. Many authors have worked on the TLC of basic dyes. Experimental conditions for separations are summarised in the following Table 128. 

On the other hand, Salo [80] has separated numerous p-hydroxybenzoates (C1--C12) on mixed layers of polyamide powder (Firm 153) and acetylated cellulose powder (Firm 83) (90 + 10), using Shell Sol A-acetic acid (83 + 17) as solvent. 

Salo and co-workers have separated artificial sweeteners on mixed layers of acetylated cellulose and polyamide [82]. A good separation of dulcin (hi / 66), saccharin (47) and cyclamate (28) was possible using the solvent Shell Sol A-n-propanol-acetic acid-formic acid (75 + 10 + 12 + 3). Rhodamine B (Rgt. No. 220) or dichlorofluorescein (Rgt. No. 63) were used for detection. The layers were prepared from 9 g acetylated cellulose powder (MN 300 Ac, Firm 83) and 6 g polyamide powder for TLC (Firm 153). These were mechanically mixed into a homogeneous suspension with 60 ml methanol and then spread the layers were dried for 10 min at 70° C. A 10 cm run took about 25 min at chamber saturation. 

Our own experiments have shown that the addition of 10—20% cellulose powder to the suspension of polyamide powder in methanol gives a more stable layer, yet does not affect the hi /-values. Thin layers, between about 0.1 and 0.2 mm thickness, are best. Good separations can be obtained on polyamide layers with both water-alcohol mixtures and... 

Layer Polyamide powder solvent methanol-water-conc. ammonium hydroxide (80 4- 16 -f 4), 5—6 cm run of duration 30 min. 

Substances that have been used in this context include glass fiber (occasionally glass beads), carbon fiber, carbon nanotubes, carbon black, graphite, fuUerenes, graphite chemically modified clays and montmorillonites, silica, and mineral alumina. Other additions have been included in polymer formulations, including calcium carbonate, barium sulfate, and various miscellaneous agents, such as aluminum metal, oak husks, cocoa shells, basalt fiber, silicone, rubbery elastomers, and polyamide powders. The effects of such additions of polymer properties are discussed next. 

Dyes can be extracted from oils and fats and from chocolates in light petroleum (boiling range 40 to 60 C). The light petroleum is shaken with dimethylformamide (I) and phase I is separated and mixed with an equal volume of water. A portion of solution I is applied to a column (25 cm x IS mm) packed with polyamide powder MNSC6. The column is washed with water to remove solution I. The dyes can be eluted with different solvents (45). 

Nail lacquers are digested with ethyl acetate and the digest is extracted with aqueous 50% dimethylformamide. The lower dimethylformamide phase is separated and, after extraction with high petroleum to remove fat, is mixed with polyamide powder on which the dye is adsorbed. The powder is packed in a column and washed with methanol. The dye is then eluted with concentrated aqueous NH3-methanol(l 19) (63). 

Polyamide powder has been proposed in batch experiments for the extraction and HPLC-DAD determination of Sunset Yellow and 13 other synthetic food colorants in fish roe and caviar [23]. This extraction method obtained better recovery rates than other solid materials (AI2O3, XAD-2, anion exchangers) also tested in this work. The sample preparation proposed by Kirschbaum consisted of the extraction of colorants from roe with 1 M aqueous ammonia, defatting with n-hexane, adjustment of the extract to pH 2, adsorption of colorants on polyamide, and desorption with a mixture of aqueous ammonia (25% v/v) and methanol (10 90% v/v) [23]. 

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