With a background as a chemist performing elemental analysis, I can remember an instance when I was rushing to analyze multiple sample sets on my ICP-OES in the same week. I had completed the first set and was rushing to swap out my sample introduction components to start my next set of analyses. In my haste, I accidentally switched the coolant and auxiliary gas lines for the torch. I headed for the wet lab to collect my new set of samples while the instrument went through its plasma ignition sequence. When I got to the doorway, I paused….something didn’t sound right.
I looked back at my ICP-OES, trying to figure out the source of the noise as it completed its ignition sequence.
POP! The plasma ignited.
“NOOOOOO!” I ran to the instrument, suddenly realizing what the problem was. Because I’d reversed the gas lines, the torch was seconds away from melting into the load coil. I ripped open the torchbox door to trigger the interlock and extinguish the plasma. Luckily, my cat-like reflexes allowed me to turn off the plasma before too much damage had been done. After replacing the torch, I was off and running again. As far as I know, that damaged torch is still used as a visual aid of “how not to set up your sample introduction components” during in-house training classes.
If Only I’d Had an iCAP
Looking back on that experience now, I think to myself, “if only I’d had an iCAP!” The Thermo Scientific iCAP 7000 ICP-OES, iCAP Q ICP-MS and iCAP RQ instruments all utilize torches with built-in gas fittings. Not a single manual connection is required. You couldn’t plumb it incorrectly, even if you tried! Not only that, the entire sample introduction setup on those instruments consists of push-fit connections. You could be scattered in a dozen directions, trying to keep up with all your various laboratory tasks, and you’d never connect your sample introduction components incorrectly.
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Image 1. Push fit sample introduction system.
I can think of another instance when I had been running oil samples for most of the day and got an urgent, last-minute request to analyze a couple of wastewater samples. After shutting down the plasma, I quickly opened the torchbox door and started swapping out the sample introduction components for ones more suited for aqueous analysis. As I rummaged through my storage drawer, I suddenly heard a CRACK and looked up to see that the glass on the torchbox door had shattered. Lesson learned: leave the instrument alone for 10 minutes after shutting down the plasma to allow the torchbox area to cool properly. If I’d had an iCAP 7000, I could have switched between organics and aqueous samples as quickly as my hands could swap the components in and out. The interlocked, high-velocity air flow inside the sample introduction area keeps the torchbox from getting too hot.
One final memory that comes to mind was when I was measuring elemental impurities in magnesium sulfate samples. Magnesium sulfate is delightfully soluble in water or dilute acid, so I whipped through my sample preparation, prepared my matrix-matched standards, and started my analysis. My sample introduction components and instrument operating conditions had been well-chosen, and I was sure I would breeze through the samples. I was so confident, that I stood right in front of the sample introduction area and watched my samples travel from the nebulizer, through the spray chamber and to the plasma.
All of a sudden…WHIFF! POP! “Ow!”
The lesson I learned that day was that magnesium sulfate rapidly precipitates out of solution as the nebulized aerosol reaches the torch injector. In fact, precipitation occurs so quickly and clogs the injector so completely that the plasma extinguishes and an instant backpressure builds up. The backpressure causes the nebulizer to fly out of the spray chamber, hitting anyone who is foolish enough to stand in front of the instrument and watch their samples run. If I’d had an iCAP 7000 or an iCAP RQ, I could have used the intelligent, online autodilution capabilities of both instruments to reduce the dissolved solid content of the samples, prior to nebulization.
These are just a few examples of why there’s a lot to like about iCAP. I’ll be publishing future blog posts about how the iCAP family of instruments can address common (and sometimes comical) lab frustrations. In the meantime, please share a funny laboratory-related story of your own or tell me about something that frustrates you in your day-to-day laboratory activities.