Test Procedure for
IDENTIFYING ADHESION COATINGS ON TRAFFIC BEADS
TxDOT Designation: Tex-833-B
Effective Date: August 2002
1. SCOPE
1.1 Use this method to detect the presence of adhesion coating on Texas Type III traffic
beads.
1.2 The values given in parentheses (if provided) are not standard and may not be exact
mathematical conversions. Use each system of units separately. Combining values from
the two systems may result in nonconformance with the standard.
2. APPARATUS
2.1 Buchner funnel.
2.2 Suction flask.
2.3 Vacuum pump.
2.4 Ultraviolet light source.
2.5 Laboratory drying oven.
2.6 Analytical balance.
2.7 Eye protection.
2.8 Rubber gloves.
2.9 Graduated cylinder, 10 ml (0.30 fl. oz.).
2.10 Beaker, 50 ml (1.5 fl. oz.).
2.11 Spatula.
3. MATERIALS
3.1 Dansyl chloride.
3.2 Acetone, reagent grade.
3.3 Filter paper, #2, 90 mm (3.6 in.) diameter, qualitative, to fit Buchner funnel.
3.4 Glass filter paper, 100 mm (4 in.) diameter.
3.5 Squirt bottle, filled with acetone.
3.6 Small aluminum weighing dishes, two per sample.
4. SAFETY ISSUES
4.1 Dansyl chloride is a hazardous compound. Do not get on skin. Wear eye protection and
gloves. Dispose of used reagents, filter paper and tested beads properly.
5. PROCEDURE
5.1 Set the drying oven to 60°C (140°F).
5.2 Assemble the Buchner funnel filtration system.
5.3 Prepare a solution of dansyl chloride by dissolving 0.2 g in 25 ml (0.75 fl. oz) of acetone.
Note 1—Store the solution in a dark glass container and use for several tests during the
day, but prepare fresh daily. This is enough dansyl chloride solution for five tests by this
procedure.
5.4 Weigh 10 g of the beads to be evaluated into a 50 ml (1.5 fl. oz.) beaker and 10 g into an
aluminum weighing dish.
Note 2—You will use the beads in the aluminum dish for comparison.
5.5 Cover the beads in the beaker with dansyl chloride solution. 5 ml (0.15 fl. oz.) will cover
10 g of beads in a 50 ml (1.5 fl. oz.) beaker. Let sit for 60 seconds.
5.6 Place a filter paper in the Buchner funnel. Wet the filter with acetone and draw vacuum.
After the filter is snuggly in place, cut the vacuum off.
5.7 While retaining the beads in the 50 ml (1.5 fl. oz.) beaker, decant the dansyl chloride
solution in to the Buchner funnel. Draw vacuum. Rinse the beads in the beaker with
10 ml (0.30 fl. oz.) acetone. Decant the rinse through the funnel. Finally, wash the beads
from the beaker on to the filter using the acetone squirt bottle while drawing vacuum.
5.8 Shut vacuum off. Rinse the beads further by adding 25 to 30 ml (0.75 to 1 fl. oz.) of
acetone to the filtration funnel then drawing vacuum
5.9 After transferring all the liquid to the filtration flask, transfer the beads to another
aluminum weighing dish.
5.10 Place the treated beads in a drying oven for 10 minutes or until the beads flow freely.
After drying, use the spatula to break any agglomerations of beads.
6. RESULTS
6.1 Place the treated beads on a glass filter paper and view under ultraviolet light. Do the
same for the untreated comparison sample. Properly coated beads will emit a yellow
green fluorescence.