Column packing fittings

A 16-in. column packed with platinum gauae and fitted with a variable take-off was used by the submitters. The checkers used a 20 X jacketed column packed with... 

Katz et al. [1] also examined the effect of particle diameter on resistance to mass transfer constant (C). They employed columns packed with 3.2 im, 4.4 p,m, 7.8 pm, and 17.5 pm, and obtained HETP curves for the solute benzyl acetate in 4.3%w/w of ethyl acetate in n-heptane on each column. The data were curve fitted to the Van Deemter equation and the values for the A, B and C terms for all four columns extracted. A graph relating the value of the (C) term with the square of the particle diameter is shown in Figure 8. 

Because hydrolytic reactions are reversible, they are seldom carried out in batch wise processes [26,28,36,70]. The reactor is usually a double jacket cylindrical flask fitted with a reflux condenser, magnetic stirrer, and thermometer connected with an ultrathermostat. The catalyst is added to the reaction mixture when the desired temperature has been reached [71,72]. A nitrogen atmosphere is used when the reactants are sensitive to atmospheric oxygen [36]. Dynamic methods require more complicated, but they have been widely used in preparative work as well as in kinetic studies of hydrolysis [72-74]. The reaction usually consists of a column packed with a layer of the resin and carrying a continuous flow of the reaction mixture. The equilibrium can... 

Copper, aluminum, stainless steel, nickel, or glass tubes bent into various shapes to fit the dimensions of the column oven provide the container for column packings [126]. Neither copper mor aluminum tubing is recommended as both metals are readily SKlditsd active, oxide-coated films formed on the inner walls promote decomposition or tailing of labile and polar solutes. Ptalnless steel is adequate for nonpolar samples but its catalytic activity precludes the analysis of labile solutes. Nickel, after acid passivation, and glass are the most inert column materials. 

To a 500-ml. round-bottomed flask fitted with a 25- to 30-cm. column packed with glass helices to which is attached a water... 

The submitters used a 7 X 300-mm. externally heated column packed with a helix of Chromel wire and fitted with a partial reflux head.3... 

The identification of the pertinent HETP equation must, therefore, be arrived at from the results of a sequential series of experiments. Firstly, all the equations must be fitted to a series of (H) and (u) data sets and those equations that give positive and real values for the constants of the equations identified. The explicit form of those equations that satisfy the preliminary data, must then be tested against a series of data sets that have been obtained from different chromatographic systems. Such systems might involve columns packed with different size particles or employ mobile phases or solutes having different but known physical properties. 

HPLC and Isolation of Mutagenic Fractions. Analytical and semipreparative reverse-phase HPLC separations were performed by using a water-to-acetonitrile linear gradient (J2). Separations were carried out on a Hewlett Packard Model 10084 B equipped with an automatic sampling device, a solvent programmer, a variable absorbance detector, and an automatically steered fraction collector. The instrument was fitted with a 3.9-mm X 30-cm prepacked analytical column of 10-/zm silica particles bonded with octadecylsilane (Bondapack-Cis) for analytical scale. For semipreparative scale separations, the HPLC was fitted with a 7.8-mm X 30-cm prepacked column packed with 10-/xm silica particles bonded with octadecylsilane. Samples for HPLC were injected at volumes of 20 /xL (flow rate 1 mL/min) and 80 /zL (flow rate 4 mL/min), and the absorption was measured at 254 nm. Fractions... 

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