| 摘要 |
PURPOSE:To enhance the measurement accuracy by adding a buffer, previously dissolved with orthophenylenediamine, to a sample and causing reaction while conditioning the pH to a specified value and to shorten the measuring time by making convenient the operation. CONSTITUTION:Orthophenylenediamine is previously dissolved into a buffer which is added to a predetermined quantity of sample of processed drink or food or preprocessed liquid thereof thus causing reaction while conditioning pH in the range of 2.5-7.0. In other words, diacetyl contained in the processed drink or food or the preprocessed liquid thereof is caused to react on othrophenylenediamine while conditioning pH to convert diacetyl into 2,3- dimethylqiunoxaline. It is further subjected to deoxygenation and fed to differential pulse voltammetry. In the deoxygenation, nitrogen gas is fed into the solution caused to react after conditioning of pH thus removing the dissolved oxygen from the solution. When the dissolved oxygen is not removed, the sensitivity is lowered. |
