| Based on Eastman lab testing, the optimum treatment for Tenite Butyrate, Tenite Propionate and Tenite Acetate cellulosic formulas is a 5% sodium hydroxide solution for 10 minutes at 140?F, rinsed in a 30% acetic acid solution followed by a thorough water rinse.
Procedure
- Dip the Tenite cellulosic part into a 5% sodium hydroxide (NaOH) solution at 140?F for 10 minutes. (solution must be maintained at 5% and at 140?F for consistent results).
- Dip into a 30% acetic acid solution and out, thus rinsing off the sodium hydroxide.
- Dip into a water bath (distilled water is preferred; however, tap water will suffice) several times, rinsing off the acetic acid.
- Air dry.
Additional Comments
Tenite Butyrate and Tenite Propionate cellulosics show adequate treatment in a 5 to 15% concentration range. Over-treatment can occur in Tenite Acetate cellulosics when a 5% concentration is exceeded. It is important to keep the sodium hydroxide concentration constant with frequent monitoring of the bath.
The acetic acid rinse is used to minimize 'over-coating' or any other problems from the residual sodium hydroxide. The acid wash may be optional provided adequate controls can otherwise be employed to avoid over-treatment.
A 2 to 20 minute time variation did not reveal any change in treatment at a given concentration and temperature. More uniform results appeared to occur at the 140?F temperature. The sodium hydroxide and acetic acid solutions are usable for a period of upto 48 hours or the equivalent time to process ~300 specimens. This, of course, could vary somewhat depending on the particular set-up.
In lab tests, the treatment remained effective for over 20 washings with fog residence times less than 3? seconds. After approximately three washing, the time for the fog to dissipate is maintained within a ? second for the remaining 20 washes. Untreated samples require ~nine seconds before clearing. |