I encounter an incident recently in our lab where the ICP torch in the 5100 OES instrument melted after only having the instrument on for ~90 min to do a quick Read of one pure known standard solution. The instrument and plasma turn on and extinguished okay without issue but the next day after opening the Torch chamber I seen the top of the torch had melted down to just above the RF coil. What was even more surprising is that the instrument hadn't registered any warning or errors from the torch melting.
After having an engineer call out he ruled out the following possible causes:
1. RF coil contact with torch
2. Insufficient coil / torch cooling - chiller unit operating correctly with no coolant flow obstruction.
3. Exhaust / extraction system
The engineer stated they had never seen this type of torch melt down pattern before so couldn't assign a definitive cause especially when the instrument software hadn't registered any errors and the instrument seemed to be operating within its parameters during their inspection. However he did notice that the seal on the OneNeb nebuliser in the spray chamber wasn't on correctly so small amount of Oxygen could have gotten into the torch and caused the plasma to burn hotter than normal or not cool down as quickly during the extinguishing sequence.
My own thoughts on this was since we clean the torch every week by soaking in aqua regia that over time the strong solution has been weakening the quartz torch but I can't find any information to support this.
Has anyone else experienced something similar to this in their ICP experience?