Girard's Reagent T (Trimethylacetohydrazideammonium Chloride) is a biochemical reagent. Girard's Reagent T under mild acid or alkaline conditions, reacts with aldehydes and ketones containing α-dicarbonyl functional groups to produce addition compounds which strongly absorb ultraviolet light.

Instructions
Derivatization of aldehydes and ketones:
1. Method: When performing derivatization, first dissolve the sample in an appropriate solvent (such as water, methanol, dichloromethane, etc.). Then, add a certain amount of Girard's Reagent T (usually a molar ratio of 1:1 to 1:10). Heat the reaction mixture to 50–60°C and react for 1–2 hours, then separate the derivative by extraction, concentration or other means.
2. Amount of Girard's Reagent T:
Amount of reagent: Depending on the requirements of the derivatization reaction, the amount of Girard's Reagent T is usually a molar ratio of 1:1 to 1:10 (molar ratio of Girard's Reagent T to the aldehyde or ketone to be derivatized). For complex samples, a higher ratio may be required.
Solvent: The amount of solvent usually used is 5–10 times the volume of the sample. The choice of solvent is usually determined by the nature of the sample being treated, such as methanol, ethanol, dichloromethane, etc.
3. Mass spectrometry:
For mass spectrometry, the GR-T is often used to derivatize samples to increase the volatility and polarity of compounds. Aldehydes and ketones can be rapidly derivatized by simple mixing, heating, or cooling. Commonly used solvents are methanol or dichloromethane, and the reaction temperature is usually between room temperature and 60°C.
Note: After the reaction, the derivatives can be purified by nitrogen drying, extraction, or column chromatography. The purification method in this step depends on the nature of the sample and the solvent used.