[Determination of molybdenum in supported catalysts by ICP-AES].

The supported Mo catalysts were pretreated using hydrofluoric acid. Then Mo was determined by inductively coupled plasma atomic emission spectrometry(ICP-AES). In the present method, the detection limit of Mo was 8.220 ng x mL(-1), the recovery of standard addition was 102.6%-104.3%, the relative standard deviation (n = 11) was less than 0.860%. The method is efficient, accurate, and easy to operate. Molybdenum in supported catalysts, which were prepared under different conditions, was determined by this method. The results showed that the content of Mo in supported catalysts decreased after preparation. The decreases in the content of Mo were different when the active component concentrations in impregnation solution, and the calcination temperature, changed.

[Pretreatment of supported Wacker catalysts and the determination of palladium and copper].

The supported Wacker catalysts were pretreated with two different methods. Then copper and palladium were determined by inductively coupled plasma atomic emission spectrometry(ICP-AES). The results showed that the best pretreatment method is burning-acid dissolving. With this method, the detection limits of Pd and Cu were 3.127 and 2.548 ng x mL(-1), the recoveries of standard addition of Pd and Cu were 96.26% and 94.82%, and the relative standard deviations (n=11) of Pd and Cu were less than 1.237% and 1.354%, respectively. The method is efficient, accurate, and easy to operate. Pd and Cu in supported Wacker catalysts, which were sampled before calcination, after calcination and after reaction, were determined by this method, and the contents were compared with calculated values. The percentages were larger than 96.4% and 96.6% respectively. It is considered that the active components did not decrease in preparation and reaction.