Potassium dodecylsulfate

If potassium ions are present within the sample, potassium dodecylsulfate precipitates and dodecylsulfate ion concentration is... 

Smith et aiused ion-pair chromatography to separate apomorphine and related alkaloids. A diphenylsilane column was used in combination with methanol - acetonitrile -0.02 M aqueous potassium dihydrogen phosphate - 0.03 M citric acid (pH 3.25) containing 0.001 M sodium dodecylsulfate (36 9 55). The system allowed baseline separation of apomorphine, apocodeine, isoapocodeine and the internal standard N-n-propylnorapomorphine or boldine. Dodecylsulfate as counter-ion gave better results than heptanesulfonic acid. Without the addition of a pairing-ion, tailing was observed. 

Fig. 6. Kinetics of immobilization of glutaryl-7-ACA-acylase on epoxy-activated polymethacrylate. The Gl-7-ACA-acylase was incubated with the epoxy-activated carrier. At definite times aliquots were taken from the reaction suspension. Supernatant and carrier-fixed enzyme were separated by centrifugation. The carrier-fixed enzyme was washed with water to remove non-covalently linked enzyme. The activities of the immobilized enzyme and supernatant were determined (5 mM potassium phosphate buffer pH 8,37°C, 2% glutaryl-7-amino cepha-losporanic acid, pH-stat 8.0). Simultaneously, an aliquot of carrier-fixed enzyme was boiled in sodium dodecylsulfate (SDS)/glycine buffer and the supernatant was subjected to SDS-polyacrylamide electrophoresis (see insert from left to right lane 1 Carrier-fixed enzyme, 2 h lane 2 Carrier-fixed enzyme, 4 h lane 3 Carrier-fixed enzyme, 6 h lane 4 Carrier-fixed enzyme, 21 h lane 5 Carrier-fixed enzyme, 69 h lane 6 Dialyzed enzyme lane 7 Supernatant, 2 h lane 8 Supernatant, 21 h lane 9 Supernatant, 69 h lane 10 Molecular weight calibration markers)...

The N alkylacrylamides were copolymerized with acrylamide via micellar copolymerization using sodium dodecylsulfate as the surfactant and potassium persulfate as the free-radical initiator. Monomer feed mole ratios were varied from 0.25 99.75 to 0.75 99.25 N-alkylacrylamide acrylamide. Following reaction, the polymers were purified by precipitation in acetone, dialysis, and lyophilization. Elemental analysis confirmed the absence of surfactant in the copolymers. 

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