In one of my previous blog posts, I told a series of anecdotal hiccups that happened to me during my days as a trace elemental application chemist. After reading several comments and stories, it’s nice to know that I share some common (and comical) experiences in the lab. A very familiar theme among these shared experiences involves sample introduction plumbing.
I can remember a number of instances when I’d been working long hours, running many, many samples and trying to spend as little time as possible doing any sort of instrument maintenance. With carefully prepared samples and proper rinsing between samples and sample sets, many of the sample introduction components could sustain relatively long periods of analysis - except for the peristaltic pump tubing.
No matter how dilute the sample matrix or how carefully the samples are prepared, the uptake and drain tubing are subject to constant physical abuse as they get crushed beneath the pump platens. In one memorable incident, the harsh reality of this fact would set in on the fifth straight day of analysis when I checked on my sample sequence and discovered that acidified solution had been pouring over the peristaltic pump and onto the floor for the past hour.
Even worse were times when I was attempting to multi-task or I was hurrying to install a new set of pump tubing and I connected the drain tubing backwards. In a rush to get moving with my sample analyses, I would assume I’d connected it correctly and I would turn the instrument’s plasma and pump on, before dashing to the wet lab to finish preparing my samples for the day. Embarrassment, horror and anger would then set in when I’d hear the plasma go out because the spray chamber had filled with solution and transferred that solution up to the torch.
If Only I’d Had an iCAP
At this point, you would be wise to be thinking, “if only I’d had an iCAP!” The Thermo Scientific™ iCAP™ 7000 ICP-OES features a peristaltic pump with a built-in drain sensor to tackle these sorts of plumbing problems.
The drain sensor is a unique innovation that uses an optical device to detect liquid flow as it’s pumped through the drain tubing of the spray chamber. In the event that the tubing becomes blocked, disconnected or ruptured (or gets installed backwards), the drain sensor determines that solution has stopped draining properly from the spray chamber then automatically shuts down the plasma and stops the peristaltic pump. In addition to protecting the instrument during unattended operation, this feature also prevents the consumption of samples that can’t be properly transported to the plasma. This is just another reason why there’s a lot to like about iCAP.