Q: Why is it that the 2% diluted Solujet only has a shelf life of 2 weeks from the date of dilution? This differs radically from the 2 year shelf life of concentrated Solujet. Sure isn’t there a mistake? What about other detergents?
A: A very fair and common question.
As a concentrate, there is insufficient water present to support cell walled organisms that biodegrade the detergent. Osmotic pressure bursts the cell walls and microbes do not survive in the concentrated detergent. As dilute detergent, there is sufficient water present to allow for the possibility of microbial growth on this biodegradable detergent. We have tested and found that the detergent is stable for 2 weeks. Beyond 2 weeks there is increasing risk of microbial growth. In Solujet® Low-Foaming Phosphate-Free Liquid with a pH around 12, there are not many micro-organisms that can survive. But of course, there are some, and these include alkalinophiles. These types of microbes are somewhat rare and it is very possible that the Solujet diluted solution will last longer than 2 weeks before microbial growth begins to break down the detergent.
There are additional hydrolysis reactions that slowly degrade the detergent, these reactions go faster in the dilute solution in the presence of more water. We acknowledge that 2 weeks is a conservative shelf life. However, a less conservative shelf life for diluted Solujet solution would be measured in weeks, not the years that the concentrate’s shelf life is stable.
Note that while the above explanation can generally apply to all Alconox Inc. detergents, those with pH closer to neutral will of course be more susceptible to microbial growth. This means most of the manual, high foaming detergents. Hence, we recommend a shelf life for diluted detergent of up to 2 weeks under closed laboratory conditions to have a conservative blanket statement.
Detergents to which the two week diluted shelf life recommendation apply, in addition to the aforementioned Solujet detergent, include:
- Alconox® Powdered Precision Cleaner
- Liquinox® Critical Cleaning Liquid Detergent
- Alcojet® Low Foaming Powdered Detergent
- Detojet® Low Foaming Liquid Detergent
- Detergent 8® Low-Foaming Ion-Free Detergent
- Luminox® Low-Foaming Neutral pH Liquid Detergent
- Solujet® Low-Foaming Phosphate-Free Liquid
- Tergajet® Low-Foaming Phosphate-Free Detergent
- Citranox® Liquid Acid Cleaner and Detergent
- Citrajet® Low-Foam Liquid Acid Cleaner/Rinse
- Alcotabs® Tablet Pipet Detergent
- Detonox® Ultimate Precision Cleaner
- Keylajet® Low-foaming High Alkaline Liquid
There is a single exception to this. Tergazyme® Enzyme-Active Powdered Detergent, due to the presence of proteolytic enzymes, needs to be used within 8 hours once made into solution. These enzymes, made of proteins themselves, may begin to degrade each other or autocatalyze after that time and thereby lessen the effectiveness of the detergent.
To request an Alconox Inc. detergent for free, please complete the questionnaire at Get Sample. For more information about any one of our Alconox Inc. detergents, consult the technical bulletin for each product. Or click here to access each of our detergent’s Safety Data Sheets.
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