ELAN 9000

Hi all. Just found this forum and it looks like it is a great resource for analytical chemists. I was doing a search on the internets trying to find an answer to a problem we are having with our PE elan 9000. Maybe someone can offer some help...

Our ICP was recently repaired by our PE service guy. We had multiple problems: We had a couple boards replaced, and our RF generator had failed and needed to be serviced. Due to the highly corrosive environment which is our lab, we constantly struggle with keeping our electronics functioning and preventing metal surface from oxidizing.

Following repairs we fired it back up and optimized. While our other settings did not change significantly (lens voltage, RF power, analog/pulse stage voltage) the Neb flow changed dramatically. For the life of the instrument, our Neb flow optimized between 1.1 - 1.2 L/m. Following repairs, it optimized at 0.7 L/m. Thinking the instrument may run differently with the overhaul we had just done, we started analysis. Initially, instrument reponse was approximately what it was before the repair, but it we quickly lost 75-80 % of that within the first few hours. Thinking the Neb flow actually be an issue, we hooked up a flow meter in line. Our flow meter indicated that the true flow was 1.2-1.3 L/m, while the software was reading 0.7 L/m.
We have a follow up call in to our service rep, but he can be a while to answer. I was just wondering if anyone here had any insight as to what may be causing this problem. Are the new boards not regulating the mass flow controllers properly now. Or has the MF controllers possibly pooped the bed? Can anyone think of a way to check this? 

BTW, introduction of sample to the instrument is in gas (not with a nebulizer) and is a pretty clean analysis. More or less, we run it at idle speed.

Thanks for any insight anyone may have.

Have you run Mass calibration, dual detector, Auto lens and other tests after repairying.
Give details about Neb flow, RF power, Lens voltage and auto lenns data.
How about daily performance report ?

If you did not have a pre-repair reading, I would not put too much stock into the flow reading. My work environment is fairly hostile also, but it is not much of an issue for our 9000's....are you under a service contract?  When you adjust your neb. flow do you do it based on oxides, best intensity, or manually?

We're unsure that the most recent repair had anything to do with it, but I'm thinking it did. We had to have a board replaced because the water temp sensor was not reading accurately. The sensor was fine, it turned out that the board was faulty. Since that board was replaced, the neb flow now optimized at 0.7 l/m. Previous to the board being replaced, the neb flow has always optimized b/t 1.1 - 1.2 l/m. We checked the neb flow with a flow meter. While the instrument was set at 0.7 l/m, the flow meter read 1.2 l/m. For whatever reason, we are not getting proper control of the MF controller from the software, and I'm hypothesizing that the new board is not communicating with the MF controller properly. I was just wondering if anyone had a way to independantly check the ouput from the board to see if it was putting forth the appropriate voltage at a setting to verify if it was the board that is not functioning or if it was the MF controller.

We are not under a service contract, this is the only ICP-MS that we operate. We are considering it though. This is the sixth board we've had to have replaced on this instrument in three years. We optimize our instrument for max intensity. We analyze environmental samples for Hg, and most samples are at or near our DL. We optimize by introducing a steady stream of gaseous elemental Hg and adjusting to achieve max response. And like I said in the OP, all our work is done in a gas stream-we don't even own a nebulizer.

Thanks for the responses so far.