FAQ: “We currently heat 5 g of sample and visually inspect it for APHA/Pt-Co Color, but would like to have a quantitative measurement. We would like to go ahead and order the vials and cell holder following your hot liquids color method. However, I have a question regarding the vials. According to the brochure, the black polypropylene caps can only be heated to 110C, and we need to heat to 200C. I was planning on heating samples in our oven, but it looks like that’s not going to work if we use those caps. Is there a cap we can order that is compatible with the vials and can be used at high temperatures?”
Depending on the formulation and density, the polypropylene caps melt from 130 to 171 C (266 to 340 F). Aluminum melts at a much higher 660 C (1220 F).
Just for reference the clear borosilicate glass in the vials melts at 820 C (1510 F).
The 24 mm ID vials (20 ml, 40 ml, 60 ml) have a 24mm x 400 style thread and the black polypropylene caps that come with the vials match that.
Aluminum metal caps of the same size and rating 24-400 (24mm x 400 style thread) can be purchased separately from any source. Here is one from the internet:
Bath Body Supply http://www.bathbodysupply.com/product-p/clst05.htm
An alternative is to use metal foil as an enclosure to cover the vials.