High pH Electrolyte Research Articles

Nanoporous Titanium Oxide Morphologies Produced by Anodizing of Titanium

AbstractA quick and dependable technique has been developed that allows us to selectively produce anodized TiO2 in the form of nanotubes. The process employs mild chemical conditions and ambient temperature. The method can consistently produce nearly 100% surface coverage of nanotubes within 10 min of anodizing. Anodizing in relatively high pH electrolytes for 1 hour permitted us to produce nanotubes of 2μm length. We attribute the repeatability of our results to a brief pre-anodizing etching step that consistently leads to excellent anodizing results. Without this etching step, we experienced very poor consistency in that only small patches of titania nanotubes were formed.

Corrosion of polyaniline-coated steel in high pH electrolytes

Cyclic polarization measurements made on steel, iron oxalate-coated steel and polyaniline in a high pH solution and in the absence of chloride ions showed no tendency of the surface towards pitting corrosion. In all cases, the pitting potential was similar to the protection potential. Chlorides in the caustic solution caused significant pitting in the bare steel and slight pitting in the oxalate coated steel. The polyaniline coated-steel showed no pitting in the chloride-containing alkaline solution. Scratches through the polyaniline coating did not initiate pitting in the polyaniline coated steel surface when tested in the chloride-containing solutions.

Trace analysis of detergent residues by capillary electrophoresis

A capillary electrophoresis (CE) method is reported which allows both specific and sensitive detection of the surfactant sodium dodecylbenzenesulphonate (SDBS) at a trace level. The method employs a simple high pH electrolyte with detection at 200 nm. This method has been applied to the monitoring of detergent residues on pharmaceutical processing equipment left after cleaning. Successful validation of the method demonstrated acceptable levels of sensitivity, recovery, precision, repeatability, robustness, detector linearity and stability of standards, reagents and samples. The CE method for determination of detergent residue was demonstrated to be selective with no interference from dissolving water or from cotton wool extracts. The method is rapid and both simple and easy to perform, and is now routinely applied to monitor detergent residues following product manufacture.