Dabsyl chloride (DABS-Cl) is an amine derivatizing agent and able to give rise to stable products that can be easily monitored spectrophotometrically at 460 nm.

Instructions
I. Solution preparation
1. Mother solution preparation: Dabsyl chloride is usually dissolved in organic solvents such as dimethyl sulfoxide (DMSO) or acetone. If it is needed for a specific reaction, it can also be dissolved in water.
2. Working solution preparation: Dilute the mother solution into the working solution when using it, adjust it according to the specific experimental conditions, and set a concentration gradient if necessary.
II. Operation steps
1. Labeling reaction: Dabsyl chloride is labeled with free amine groups (such as amino acids or proteins) through nucleophilic substitution reactions. The amine groups of the target molecules react with Dabsyl chloride to form stable dabsyl products.
3. Reaction conditions:
Buffer: The reaction is usually carried out in a weakly alkaline solution with a pH value generally between 8.5 and 9.5.
Temperature: The reaction is carried out at room temperature. If the reaction needs to be accelerated, the temperature can be appropriately increased.
Reaction time: The reaction time varies depending on the concentration of the amine group and Dabsyl chloride, usually 30 minutes to 1 hour.
4. Product detection:
The generated dabsylation product usually has a characteristic absorption peak at 460 nm in a UV-Vis spectrophotometer, which can be used to quantitatively detect the labeling efficiency.
5. Purification:
After the reaction, unreacted Dabsyl chloride and free amine groups can be removed by dialysis, gel filtration or chromatography, depending on the size of the labeled molecule.