抄録
A method of assaying gelatin in acidic copper plating baths was investigated, and gelatin content was determined indirectly in the following way. Only the gelatin in the electrolyte was bounded with a nitrocellulose (NC) filter, and the gelatin on the NC filter was allowed to react with Amido Black 10B (AB10). The AB10 was then eluted with a NaOH solution, and the absorbancy of the AB10 solution was measured. Gelatin in concentration up to 16ppm were determined without the influence of coexistent ions.
The decomposition behavior of gelatin in the electrolyte was investigated. The molecular weight of the decomposed gelatin was determined by the gel permeation chromatography, after the gelatin combined with the NC filter was eluted with a surfactant. It appeared that the gelatin decomposes with time, and that the decomposition rate is faster at higher temperatures. After standing for 240min, gelatin with a molecular weight of 70, 000 broke down to molecular weight of 25, 000, 15, 000, and 5, 000 at 32°C, 45°C, and 60°C, respectively.
