Troubleshooting Lack of Pink Color Development in Resazurin Indicator

Resazurin not turning pink

Resazurin is a commonly used indicator in science experiments, particularly in microbiology and cell culture applications. It is primarily used to monitor the presence or absence of oxygen in a system.

Under normal conditions, when resazurin is exposed to oxygen, it undergoes a chemical reaction and turns from blue to pink. This change occurs due to the reduction of resazurin by oxygen, forming a new compound called resorufin, which is pink in color

However, if resazurin is not turning pink, it could indicate several possibilities:

1. Insufficient oxygen: For the color change to occur, there must be an adequate amount of oxygen available. If there is not enough oxygen present, resazurin may not fully react and turn pink. You can try increasing the oxygen level in your system, such as providing better aeration or increasing the exposure to atmospheric oxygen

2. Incomplete reduction: Resazurin requires certain reducing agents present in the system to facilitate its full reduction to resorufin. If these reducing agents are insufficient or absent, the reaction may not occur completely, resulting in a lack of pink color. In this case, you can try adding suitable reducing agents like glucose or NADH (nicotinamide adenine dinucleotide) to your system

3. Wrong pH: Resazurin exhibits different colors at different pH levels. In an acidic environment, it may turn yellow instead of pink. Make sure the pH of your system is within the appropriate range for the pink color development

4. Degraded or expired resazurin: Resazurin can degrade over time or if stored improperly. It is important to check the expiration date on the Resazurin bottle and ensure proper storage conditions. If resazurin is outdated or degraded, it may not exhibit the expected color change

5. Contamination or interference: If there are contaminants or interfering substances present in the system, they may inhibit or interfere with the resazurin reaction, leading to a lack of pink color development. Ensure the purity of your system by filtering or removing any potential interfering substances

If resazurin is not turning pink despite troubleshooting these factors, it is advisable to consult scientific literature, protocols, or other experts in your specific experimental field for further guidance

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