Abstract:

Methanol in acid solution was oxidized to formaldehyde, which interacts with chromotropic acid, and a purple compound with a characteristic absorption peak at 574 nm is formed. Based on the above reaction principle, a novel method, chromotropic acid spectrophotography, was established to determine methanol content during fermentation of Pichia Pastoris. In methanol determination (0.05%～0.5%(m/V)), the method is good in the sense of linearity (R2＝0.999). The recovery ratio of methanol is between 99.4%～103.8%, and the relative standard deviation of determination is less than 1.49%. Compared with a result of gas chromatography (GC), the coincidence indicator is over 95.0%. The results suggest that the method is simple, fast and low priced for methanol determination.

Key words: fermentation culture, spectrophotomeric method, chromotropic acid, methanol