08:13 – We’re down to a dozen chemicals left to package, after which we’ll be ready to start assembling biology kits. Most of those are obnoxious ones in one way or another, and I always leave those for last. For example, the glycerol and sodium dodecyl sulfate solutions are extremely viscous. We’ll probably package those in wide-mouth bottles rather than standard dropper bottles, simply because it’s so hard to get the chemical into (and then out of) the dropper bottles. Then we have stuff like 6 molar solutions of sodium hydroxide, acetic acid, ammonia, and hydrochloric acid, all of which are extremely corrosive and the last three of which emit noxious and choking fumes.
Speaking of kits, I’m also putting together a list of items to go in the forensics kit. I’d like to include a small amount of concentrated nitric acid, which until recently I thought was illegal to ship in any quantity without paying a hazardous material surcharge. It turns out that I may be able to include 30 mL or less under the section 173.4 small-quantity exemption. So I started checking resistance of various materials to 68% nitric acid. It turns out that polyethylene will probably work just fine, which surprised me.
While I was at it, I decided to check resistance to 98% sulfuric acid, which is used in Marquis reagent and Mandelin reagent (presumptive drug test reagents that are essentially 98% sulfuric acid, with tiny percentages of formaldehyde and ammonium metavanadate present, respectively). To my surprise, it appears that 98% sulfuric acid is even tougher on common plastics than is 68% nitric acid.
I’d package those solutions in 10 mL glass bottles packed inside 50 mL polypropylene centrifuge tubes, but the question is what kind of cap to use on the bottles. One option is a PP cap with a PE liner. I have a sample of that bottle and cap, so I’m going to fill it with Marquis reagent and store it for a couple months inverted inside a centrifuge tube to see what the Marquis reagent does to the cap and liner.