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Chemical Stability and Compatibility

 
 

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Acid digestion for Sn-containing alloy
I am currently analyzing samples of Sn-containing alloys, and I could not get reliable result for the Sn concentration. I dissolved the sample in aqua regia and diluted the solution until the final concentration of HCL is around 3%. However, I've found that the signal coming from Sn slowly disappears over time, which indicates that the solution is not stable. I'm aware now that Sn can easily precipitate out of the solution, and that HF is almost always needed to stabilize it in the solution. The question is how much do i need to add HF?
Created: 07/18/18 14:36:54
Created By: "admin"
1 2564
Acid digestion for Sn-containing alloy
I am currently analyzing samples of Sn-containing alloys, and I could not get reliable result for the Sn concentration. I dissolved the sample in aqua regia and diluted the solution until the final concentration of HCL is around 3%. However, I've found that the signal coming from Sn slowly disappears over time, which indicates that the solution is not stable. I'm aware now that Sn can easily precipitate out of the solution, and that HF is almost always needed to stabilize it in the solution. The question is how much do i need to add HF?
Posted: 07/18/18 14:38:10
Antimony and Molybdenum Troiubleshooting
Not sure where to start with this one! We are transitioning from an ICP to an ICPMS. During the initial stages we developed our method and ran everything pretty much the same as on the ICP. Then we noticed that the translation didn't always produce the results we needed. We have since tweaked out method but are having problems with Antimony and Molybdenum. Sb is a problem child for our wastewater samples and Mo is for our sludge samples. I do not think that this is an instrumentation issue but more so one of lack of understanding as well as issues with our matrix/digestion processes (our undigested calibration curve standards look great). Our standards are all made up with a matrix of 1% Nitric/0.5% HCl. When we digest our water samples we use 50 mL of sample and .5mL of HNO3 and .25 mL of HCl and heat for 3.5 hours then bring to a 50 mL volume. With sludge samples we use 5 g of solid and bring that to a 50 mL volume, add 3.0 mLs of HNO3 and heat for 4.5 hours then add 2.0 mL of H2O2 and heat an additional 30 minutes before cooling and bringing back up to 50 mL. If anyone has any suggestions on what we should to it would be greatly appreciated. I myself am new to the ICPMS world and can use any and all the help that I can get.
Created: 08/30/18 21:08:17
Created By: "admin"
0 1335
No Data Found
Antimony and Molybdenum Troiubleshooting
Not sure where to start with this one! We are transitioning from an ICP to an ICPMS. During the initial stages we developed our method and ran everything pretty much the same as on the ICP. Then we noticed that the translation didn't always produce the results we needed. We have since tweaked out method but are having problems with Antimony and Molybdenum. Sb is a problem child for our wastewater samples and Mo is for our sludge samples. I do not think that this is an instrumentation issue but more so one of lack of understanding as well as issues with our matrix/digestion processes (our undigested calibration curve standards look great). Our standards are all made up with a matrix of 1% Nitric/0.5% HCl. When we digest our water samples we use 50 mL of sample and .5mL of HNO3 and .25 mL of HCl and heat for 3.5 hours then bring to a 50 mL volume. With sludge samples we use 5 g of solid and bring that to a 50 mL volume, add 3.0 mLs of HNO3 and heat for 4.5 hours then add 2.0 mL of H2O2 and heat an additional 30 minutes before cooling and bringing back up to 50 mL. If anyone has any suggestions on what we should to it would be greatly appreciated. I myself am new to the ICPMS world and can use any and all the help that I can get.
Created: 08/30/18 21:17:31
Created By: "admin"
0 0
No Data Found
Antimony and Molybdenum Troiubleshooting
Not sure where to start with this one! We are transitioning from an ICP to an ICPMS. During the initial stages we developed our method and ran everything pretty much the same as on the ICP. Then we noticed that the translation didn't always produce the results we needed. We have since tweaked out method but are having problems with Antimony and Molybdenum. Sb is a problem child for our wastewater samples and Mo is for our sludge samples. I do not think that this is an instrumentation issue but more so one of lack of understanding as well as issues with our matrix/digestion processes (our undigested calibration curve standards look great). Our standards are all made up with a matrix of 1% Nitric/0.5% HCl. When we digest our water samples we use 50 mL of sample and .5mL of HNO3 and .25 mL of HCl and heat for 3.5 hours then bring to a 50 mL volume. With sludge samples we use 5 g of solid and bring that to a 50 mL volume, add 3.0 mLs of HNO3 and heat for 4.5 hours then add 2.0 mL of H2O2 and heat an additional 30 minutes before cooling and bringing back up to 50 mL. If anyone has any suggestions on what we should to it would be greatly appreciated. I myself am new to the ICPMS world and can use any and all the help that I can get.
Created: 08/30/18 21:19:40
Created By: "admin"
0 0
No Data Found
Antimony and Molybdenum Troiubleshooting
Not sure where to start with this one! We are transitioning from an ICP to an ICPMS. During the initial stages we developed our method and ran everything pretty much the same as on the ICP. Then we noticed that the translation didn't always produce the results we needed. We have since tweaked out method but are having problems with Antimony and Molybdenum. Sb is a problem child for our wastewater samples and Mo is for our sludge samples. I do not think that this is an instrumentation issue but more so one of lack of understanding as well as issues with our matrix/digestion processes (our undigested calibration curve standards look great). Our standards are all made up with a matrix of 1% Nitric/0.5% HCl. When we digest our water samples we use 50 mL of sample and .5mL of HNO3 and .25 mL of HCl and heat for 3.5 hours then bring to a 50 mL volume. With sludge samples we use 5 g of solid and bring that to a 50 mL volume, add 3.0 mLs of HNO3 and heat for 4.5 hours then add 2.0 mL of H2O2 and heat an additional 30 minutes before cooling and bringing back up to 50 mL. If anyone has any suggestions on what we should to it would be greatly appreciated. I myself am new to the ICPMS world and can use any and all the help that I can get.
Created: 08/30/18 21:25:31
Created By: "admin"
0 429
No Data Found
Stabilizing Si with HF and acid digestions
I recently ordered a 1000 ppm standard of SiO2 for testing on my MP-AES. The label on the standard says there is trace amounts of hydrofluoric acid; does this help the Si stay in solution? If so, are you aware of how accurate an acid digestion for Si would be without the use of HF?
Created: 08/30/18 21:35:41
Created By: "admin"
0 460
No Data Found
Mercury containers, stability, and contamination from glass
I was looking at the two ICP-MS Hg standards (10 ppm) you offer. One in HNO3 and one in HCl. I noticed the HNO3 standard was in glass. Is there a reason for this? Do you see any issues for trace metal analysis that is running simultaneously on an ICP-MS? We run very low levels of metals with our Hg analysis on the ICP-MS and I’m concerned about the glass container. Thanks for your help!
Created: 08/30/18 21:37:57
Created By: "admin"
0 0
No Data Found
Stabilizing mercury (Hg) with gold (Au)
I am writing to get your input on the role of gold towards the stabilization of mercury. In the following link and subsequent EPA report it states that gold acts as a stabilizer for mercury. Can you please suggest if there are any ratios (either atomic or %) between Hg and Au to achieve maximum stability without the addition of too much Au? https://www.inorganicventures.com/sites/default/files/mercury_preservation_techniques.pdf Our range of Hg measurement is 0.05-20 ppb (ng/mL) for samples subjected to a 250 deg C microwave digestion at 40 bar pressure. Thank you, Looking forward to hearing from you.
Created: 08/30/18 21:41:42
Created By: "admin"
0 1172
No Data Found
Neutralizing HF with triethanolamine
Dea sirs, Thank you for the great online guides and research papers. They are extremely informative. In part 6 of the ICP Operations Guide, Dr. Paul Gaines mentions the use of triethanolamine to neutralize HF. Can you or anybody else provide more detail? For example, how much TEOA should one use after digestion with HF/HNO3? Also, what is the addition of H4EDTA for and is it necessary? Thank you for any assistance.
Created: 08/30/18 21:46:52
Created By: "admin"
0 0
No Data Found
Acid digestion for Sn-containing alloy
I am currently analyzing samples of Sn-containing alloys, and I could not get reliable result for the Sn concentration. I dissolved the sample in aqua regia and diluted the solution until the final concentration of HCL is around 3%. However, I've found that the signal coming from Sn slowly disappears over time, which indicates that the solution is not stable. I'm aware now that Sn can easily precipitate out of the solution, and that HF is almost always needed to stabilize it in the solution. The question is how much do i need to add HF?
Created: 08/30/18 21:48:44
Created By: "admin"
0 0
No Data Found