11:13 – We have everything we need to make up another batch of 60 forensic science kits except molybdate reagent, which we supply in 15 mL bottles. I made up a liter of the stuff recently, but I don’t like the looks of it. It’s a 2% w/v solution of ammonium molybdate in 32% v/v sulfuric acid, and it should be a colorless liquid. In the presence of phosphate ion and ascorbic acid (vitamin C) it reacts to form an intense blue complex that can be used for quantitative colorimetric determination of phosphate concentration. But the liter I made up is a very pale blue, which concerns me. I checked reference bottles that I made up a year ago and two years ago, and both remained colorless. So I think I’ll pitch that batch and make up a new batch.
Barbara and I decided to join Sam’s Club. We don’t particularly care for the company or its policies–particularly how it treats its employees–but Sam’s carries a lot of stuff that Costco doesn’t (and vice versa).