Sample Preparation - Si catalyst sample preparation for Ti and B analyses

It should be possible to use an acid digestion with HF, but if it’s necessary to evaporate the sample following digestion then the concern would be B volatility. For Ti, either a caustic fusion (we recommend sodium carbonate) or acid digestion would be suitable, though losses of Ti when digestions using hydrofluoric acid are evaporated have been reported. If the Si is present as a gel, then a simple room temperature digestion with HF may be sufficient (e.g., 100 mg sample with 2-3 mL HF and equal parts water). If the resulting solution is clear, then dilution with water and measurement may be suitable depending upon the required detection limits. Having some HF present will certainly help with Ti stability, though the presence of HF can be a concern for rare earths such as yttrium. However, as Y is a good ICP-OES internal standard using it should not be a concern as long any residual HF is relatively low (<0.2% v/v) and the Y concentration is 10 ppm or less.