Part Number 226-28

I was sampling for hydrogen cyanide and the sorbent inside my tube turned purple. Should I be concerned? Will it affect my samples?

There is no need for concern. Soda lime, which 226-28 sorbent tubes contain, is normally used to remove carbon dioxide.…

There is no need for concern. Soda lime, which 226-28 sorbent tubes contain, is normally used to remove carbon dioxide. Sometimes a colour indicator is put in the soda lime for this application. In the past, SKC was able to purchase soda lime without indicators, but that is no longer the case. Therefore, the purple colouration that developed inside your sorbent tubes simply means that carbon dioxide was present in the sampled atmosphere. It will not affect your hydrogen cyanide samples.

NIOSH developed Method 6010, but SKC, as the manufacturer of the sampling medium, has had to address the logistical issue of shipping. SKC places the first piece of glass wool separator into the 226-28 sorbent tube to hold the tube’s internal filter in place during shipping. Before sampling with this sorbent tube, the customer must score and break the tips off and use tweezers or other appropriate tool to remove the first glass wool separator. This preparation will allow cyanide particulate to collect onto the internal glass fibre filter.