Spectrophotometric determination of water soluble organic amides

The agglomeration of high molecular mass polyacrylamide in aqueous solutions

“…20 The method was modified slightly from that previously described 21 by installing another peristaltic pump after the detector and the addition of a T-piece prior to the detector to prevent bubbles entering the quartz flow cell.…”

Synthetic polyacrylamide as a potential flocculent to remove commercial chromium(III) oxide from aqueous suspension

“…The used solid mass was 0.07 g. Next, suspensions were shaken in a water bath for 24 h. Then, for each of them, the solid was centrifuged and 5 cm 3 of supernatant was taken for analysis. The reaction of cationic polyacrylamide with a saturated solution of bromine, sodium formate and starch (in acetate buffer) (Scoggins and Miller 1975) was applied. The formed complex gives blue colour of the solution of different intensity (depending on the polymer concentration).…”

Measuring poly(acrylamide) flocculants in fresh water using inter-polymer complex formation

“…In the EU alone approximately 50,000 tonnes of poly(acrylamide) are used per annum for effluent treatment, and the polymer also finds commercial uses in paper, pulp, mineral and crude oil processing, coating applications and soil/sand treatment 2 . Due to its high usage, concerns regarding the release of the free monomer acrylamide (known to be highly toxic 3 ) and concerns over the toxicity of anionic/cationic polymers to aquatic lifeforms [4][5][6] , researchers have long been attempting to find new methods to determine the fate of the polymer after use [7][8][9][10][11][12][13][14][15][16] . In practice the intrinsic toxicity of the polymer released to the environment is reduced by many factors 17,18 so whilst these polyelectrolytes are not a priority for environmental control, our inability to trace these synthetic polymers and determine their spread through surface waters is a severe limiting factor to their future use.…”

“…However, the methods highlighted the requirement for high temperature fusion with a highly concentrated alkali, liberating the nitrogen as either ammonia or an organic amine, and the analysis of each sample took over half an hour. Oxidation of the amide functional groups with bromine can produce an iodide ion which can be detected after the excess bromine is removed 11 . This method is both sensitive, accurate and more rapid than its predecessors but still requires modification of the polymer prior to examination; further modifications are required to allow it to work in the presence of high chloride ion concentrations 29 .…”