Optimizing the Quadruple‐potential Waveform for the Determination of Gentamicin Sulfate by High Performance Liquid Chromatography with Pulsed Electrochemical Detection
Abstract:In this paper, a quadruple-potential waveform was investigated and optimized for the determination of gentamicin by reversed phase ion-pair chromatography. Instead of a relatively high positive potential, a negative potential was adopted as a potential for the cleaning of gold working electrode. By this way, the formation of gold oxide resulting from the application of high positive potential during the analyte detection and electrode cleaning was greatly reduced, and therefore, the dissolution and recession o… Show more
“…In all these cases, the Pd is complexed by the donor atoms of the organic modification of the silica (S, As, Se). These catalysts exhibited high activity and selectivity in the Heck coupling of aryl iodides and bromides (Table ) and could easily be separated and reused. − 4 Three kinds of modified silica supported palladium catalysts.…”
Section: 4 Pd On Modified Silica (Organic−inorganic
Hybrid Support)mentioning
“…In all these cases, the Pd is complexed by the donor atoms of the organic modification of the silica (S, As, Se). These catalysts exhibited high activity and selectivity in the Heck coupling of aryl iodides and bromides (Table ) and could easily be separated and reused. − 4 Three kinds of modified silica supported palladium catalysts.…”
Section: 4 Pd On Modified Silica (Organic−inorganic
Hybrid Support)mentioning
This paper describes an improved liquid chromatography method combined with pulsed electrochemical detection for the analysis of etimicin sulfate. In total, 22 impurities could be separated. A TSK-GEL C18 column (250 mm × 4.6 mm i.d., 5 μm) is used, and the mobile phase is composed of 40 mL of acetonitrile and 960 mL of an aqueous solution containing trifluoroacetic acid (15 mL/L), pentafluoropropionic acid (500 μL/L), 50% sodium hydroxide (8 mL/L) and sodium sulfate (1.5 g/L). The pH of the aqueous solution is adjusted to 3.5 with 0.8 M sodium hydroxide. The influence of the different chromatographic parameters on the separation was investigated. A quadruple potential-time waveform was applied to the electrodes of the detection cell. 0.8 M sodium hydroxide was added post column to raise the pH to at least 12 before detection. A central composite experimental design was used to describe the relationship between factors and response values and to establish factorial analysis. Compared to previously published investigations, this improved method shows higher sensitivity, better separation ability and robustness and has been incorporated by the Chinese Pharmacopoeia 2015 for analysis of etimicin sulfate. A number of commercial samples of etimicin sulfate were also analyzed using this method.
“…The adsorption of the complexes on the imprinted membrane mainly depends on the hydrophobic interaction for these ratios. As hydrophobic interactions have no direction, the selectivity of the membrane decreased [25,26].…”
Section: Effect Of 22 0 -Bipy On the Selective Adsorption Of Membranesmentioning
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