With Clear-Seal® joints. This unit is manufactured from Wheaton 33® low extractable borosilicate glass (meets ASTM Type I Class A and USP Type I standards). Use this kit for removing interfering substances in quantitative analysis for cyanide. The sample is reacted with H2SO4 and MgCl2, which converts any cyanide to HCN. HCN distills over and is absorbed in a NaOH solution, which is then analyzed for CN. Reference: ASTM D-2036-87.