Within the vast toolkit of microbiological laboratories, certain chemical reagents are fundamental for identifying and differentiating microorganisms. Among these, 4-Dimethylaminobenzaldehyde, commonly known by its CAS number 100-10-7, stands out as Ehrlich's reagent – an indispensable component for the indole test. This simple yet powerful compound is key for many diagnostic procedures, making its consistent availability and quality a priority for lab managers.

The Indole Test: A Cornerstone of Bacterial Identification
The indole test is a biochemical test used to determine if a particular bacterium possesses the enzyme tryptophanase, which is capable of hydrolyzing the amino acid tryptophan into indole, pyruvic acid, and ammonia. The presence of indole is detected using 4-Dimethylaminobenzaldehyde. When added to a bacterial culture that has been incubated with tryptophan, DMAB reacts with any indole produced to form a red-colored complex. This distinct color change is a clear indicator of an indole-positive organism, aiding in the identification of bacteria such as Escherichia coli.

Why 4-Dimethylaminobenzaldehyde is Essential
The effectiveness of the indole test hinges on the quality of the Ehrlich's reagent. High purity 4-Dimethylaminobenzaldehyde ensures a clear and reliable color reaction, minimizing false positives or negatives. Its chemical structure, featuring an aldehyde group, readily reacts with the indole molecule. For laboratories that perform numerous biochemical tests daily, securing a consistent and high-quality supply of this reagent is critical for operational efficiency and diagnostic accuracy.

Sourcing 4-Dimethylaminobenzaldehyde (CAS 100-10-7) for Laboratories
When procuring 4-Dimethylaminobenzaldehyde for laboratory use, several factors are important. Firstly, consider the grade – analytical grade or ACS reagent grade is typically preferred for consistent performance in diagnostic tests. Secondly, look for suppliers who can provide detailed specifications and Certificates of Analysis (COA) to verify the product's purity and suitability. Many research institutions and diagnostic laboratories choose to buy from established chemical suppliers, often from China, which can offer competitive pricing for bulk purchases. This strategic sourcing allows labs to manage their budgets effectively while maintaining high standards of quality control.

Beyond Diagnostics: Other Uses
While its role in microbiology is prominent, 4-Dimethylaminobenzaldehyde also finds applications in other areas of chemistry, including organic synthesis and as a staining agent in chromatography. Its ability to react with amines and pyrroles makes it a versatile chemical tool.

In conclusion, 4-Dimethylaminobenzaldehyde (CAS 100-10-7) is a fundamental reagent in microbiological diagnostics. Its reliable performance in the indole test makes it a critical component in bacterial identification. For laboratories and procurement officers, ensuring a consistent supply of high-purity material from trusted manufacturers is essential for maintaining accurate and efficient diagnostic workflows.