Chloride column

The vinyl chloride monomer was obtained from the Ethyl Corporation and was 99.9% pure. It was washed with silver nitrate and sodium hydroxide solutions and dried over a calcium chloride column and finally trapped in dry ice - methanol traps. 

Extract sample with methylene chloride column cleanup concentrate solvent exchange to hexane... 

Well-known examples are absorption columns, for example, the absorption of HCl in an exhaust air by water. Experience shows that quite large columns are required for this purpose, whereas the equilibrium calculation just requires one theoretical stage due to the electrolyte character of hydrogen chloride. Columns like that can only be successfully designed by application of a rate-based model (see also Section 14.5). 

Run a chloride column (Section 13.7.5), using a wide (IS mm 0) column because a large amount of Fe has to be retained on the resin. 

Evaporate the eluate from the chloride column under an IR lamp. Dissolve in 8 mol/L HNO3 and run a nitrate column (Section 13.7.6). Collect the 8 mol/L HNO3 eluate in a polypropylene bottle (Pb fraction). Repeat the nitrate column if the sample is not clean enough (Section 13.7.6). 

Plate the Th (Section 13.7.7). Count lli in the alpha spectrometer. Count the beta activity using a thin plastic cover (eg., overhead sheet, 0.1mm polyester, 14mg/cm ) to absorb Th alphas and most (78 %) of Th betas. This cover lets most (91 %) of the 234mpg betas through. Calculate the Ih activity (see below for calibration factor). For decay correction, use the time of Fe(OH)3 precipitation as the time of U and Th separation. Tliis introduces some error, as some U is copredpitated and only removed in the chloride column. The contribution of other beta emitters can be quantified by repeating the beta countings and fitting the results to the decay rate of Th (Buesseler et al., 1994). 

Calibration Add 1 mL (ThVol) of spike to a weighed aliquot of the U stock solution (activity Uact, approximately 60dpm) in a small Teflon beaker. Warm, evaporate to dryness under an IR lamp, take up in 9 mol/L HO, separate Th from U by passing through a chloride column (Section 13.7.5 note time-of-separation), purify Th on a nitrate column (Section 13.7.6) and electroplate (Section 13.7.7). Count in alpha and beta counters. Calculate the calibration factor ... 

The alkali metal nitrate columns had a greater retention order than that of the corresponding alkali metal chloride columns. 

A rapid, sensitive separation of radioiodine from milk has as Its major step exchange of iodide Ion on silver chloride (119). Iodide carrier was added to the homogenized sample and the sample was stirred. (Raw milk samples were cavltated In an ultrasonic unit for homogenization.) The mixture was passed through a silver chloride column. (The exchange of Iodide on silver chloride was said to be sufficiently selective that the latter could be counted directly.) A saturated solution of chlorine In dilute sulfuric add was allowed to come In contact with the column long enough for Iodide to be oxidized to Iodic acid. 

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