Testing procedure
1. To a clean, dry 100 ml mixing cylinder graduate (KIMAX 20039-100 or equivalent), add sufficient recovered xylene so that the bottom of the meniscus is aligned with the edge of the 85 ml mark on the graduate. 2. Add water to the graduate until the bottom of the meniscus aligns with the top edge of the 100 ml mark on the graduate. At this point, 15 ml of water will have been added to 85 ml of recovered xylene. 3. Stopper the graduate and gently invert the mixture. Allow the mixture to settle, making sure that all of the water settles to the bottom of the graduate. A small amount water may remain clinging to the sides of the graduate above the xylene/water separation point. This separation point should be near the 15 ml level of the graduate. (Note: xylene floats on top of the water.) 4. Carefully inspect and record the point of separation between the water and xylene using the bottom of the meniscus as the separation point. 5. Subtract 15 ml from the quantity of water indicated in step 4. The remainder plus an additional 0.1 correction factor equals the percentage of recovered xylene impurities.
EXAMPLE
Xylene/Water separation point is indicated to be 15.5 ml, (15.5 –15) + 0.1 = 0.6% impurities. Therefore, the recovered xylene is 99.4% pure.
Note: The recommended and most accurate method of determining the purity of the recycler xylene is by doing a GC analysis. The following method can be used obtain an acceptable confidence level in the purity of the recycled xylene.
How to prepare calibration control mixture.
Establish a 1% calibration mixture. Add 5 ml of Absolute Alcohol to 495 ml of xylene to establish this mixture. Since this procedure has a number of variables the calibration mixture will be used as a standard for the person who has to perform the procedure. By testing this standard mixture the person performing the procedure can see how a 1% contamination level reads and can have confidence that all of the readings that they obtain using this method are accurate. It is recommended that this mixture be tested at the beginning of each day.