TOC/VOC EPA Septa Vials, Amber & Clear Glass. I-Chem ® offers both clear and amber borosilicate glass vials available in three sizes with the standard, 0.125 in. thick, I-Chem ® blue, PTFE/silicone septa in an open-top 24-414 polypropylene cap. Amber vials should be used for light sensitive samples. The I-Chem ® molded-in septa retainer ring