Recycled Solvent Purity Test

by brblog on July 10, 2019

Q: How do I know my recycled solvents are pure?

You can use the following quick tests to check the purity of the recycled solvents.


The Graduated Cylinder Test is a simple way to check xylene for alcohol impurities. Mix together 85 ml or xylene and 15 ml of water. If the water layer grows, then the xylene is not pure. It’s that simple.

Alcohol contamination in the xylene prefers to dissolve in water. When you mix it with water, any alcohol moves over to the water layer and that water layer will get bigger.

Xylene Purity Test Diagram


Alcohol purity is simple to test. Just let the alcohol come to room temperature and then use a hydrometer to measure the alcohol content. You can buy a hydrometer from a local scientific equipment supply house or from B/R.


The hydrometer test is very sensitive to temperature. Hot alcohol will appear to have a much higher concentration than it really does. Don’t fool yourself. Let the alcohol come to room temperature before performing the hydrometer test.

We recommend hydrometers made by companies like Fischer Scientific and VWR. They have been making them for decades and are real experts.

Stan with Test Kit


We recommend the formalin test kit from Anatech LTD. Each kit is good for more than 100 tests.

Anatech is a well-respected company in all things histology. Their test kit is very accurate and has a long shelf life.

Double Check Purity!

Need further verification of solvent purity? Some manufacturers of solvent recyclers offer additional testing at their R & D facilities. They often offer free GC analysis of solvents for a high tech evaluation of your recycled products for as long as you own your recycler.

Ask about the availability of this type of free technical support before buying a solvent recycler.

Posted in Histology Solvent Recycling, solvent recovery, Solvent Recycling

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