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Selection of Internal Standard and recommended concentration
I am conducting analysis of Cadmium, Lead, Arsenic, Mercury, Cobalt, Vanadium, Nickel, Thallium, Gold, Palladium, Iridium, Osmium, Rhodium, Ruthenium, Selenium, Silver, Platinum, Lithium, Antimony, Barium, Molybdenum, Copper, Tin and Chromium. Could anyone recommend the internal standards and their recommended concentration for these analytes? Are there any recommended ratio between the analyte signal and the internal standard signal? Thank you.
Created: 02/10/22 04:53:40
Created By: "admin"
0 508
No Data Found
Preventing IS intensity drift
What should the intensity of the IS signal be to get the best stability? I am testing cannabis samples of multiple matrix types. I see a great deal of change in the signal of the IS for plant based samples compared to the other samples and QCs. They change as much as 500%! I have controlled it somewhat by adding up to 6% isopropyl alcohol to all samples. I have an in-house IS mix of Rh, Tb, Tl and Y; the ones I have found to drift the least I adjust the concentration so the signals of all 4 are 1500 to 2000 kcps. Should they be higher? Thank you.
Created: 02/09/22 11:13:06
Created By: "admin"
0 432
No Data Found
Measuring Cs with ICP-OES
I am attempting to observe Cesium with ICP-OES. I recently created a calibration curve that consisted of 10, 100 and 1000 ppb Cesium. I observed little to no response for these solutions. My question has to do with ionization buffers. To measure Cesium, it appears that a Lithium ionization buffer would be ideal. Do you sell this solution and what concentration would be recommend adding? Also, does this ionization buffer lower the detection limit considerably or perhaps just an order of magnitude? Thank You.
Created: 11/23/21 13:07:09
Created By: "admin"
0 438
No Data Found
Lead in a Manganese Matrix
I am analyzing a manganese rich material for trace metals content. One of the analytes of interest is lead (Pb). The solution resulting from sample preparation contains ~3,000ppm Mn going into the ICP-OES (axial). When using the Pb line at 220.353nm, we consistently see a peak that equates to ~75ppm Pb in the original sample. The Pb line at 217.000nm shows no signal for lead in the sample preparation. The calibration standards are all prepared in dilute HNO3 and the r2 values are >0.99. Lead spikes into the sample preparations show good recovery on both the 220.353 and 217.000 lines. We use an internal standard to normalize matrix effects. We ran the sample preparations on ICP-MS as a 'referee' and found no signal for lead suggesting that there is something happening on the 220.353nm line. We prepared a solution containing 3,000ppm Mn from a 10,000ppm stock solution and saw the same trend on the ICP-OES with the two emission lines. I cannot find a reference to an interference at 220.353nm for manganese. Can anyone shed some light here?
Created: 08/11/21 16:14:39
Created By: "Aspen Purchasing"
3 1827
Lead in a Manganese Matrix
I am analyzing a manganese rich material for trace metals content. One of the analytes of interest is lead (Pb). The solution resulting from sample preparation contains ~3,000ppm Mn going into the ICP-OES (axial). When using the Pb line at 220.353nm, we consistently see a peak that equates to ~75ppm Pb in the original sample. The Pb line at 217.000nm shows no signal for lead in the sample preparation. The calibration standards are all prepared in dilute HNO3 and the r2 values are >0.99. Lead spikes into the sample preparations show good recovery on both the 220.353 and 217.000 lines. We use an internal standard to normalize matrix effects. We ran the sample preparations on ICP-MS as a 'referee' and found no signal for lead suggesting that there is something happening on the 220.353nm line. We prepared a solution containing 3,000ppm Mn from a 10,000ppm stock solution and saw the same trend on the ICP-OES with the two emission lines. I cannot find a reference to an interference at 220.353nm for manganese. Can anyone shed some light here?
Posted: 09/18/21 02:43:46
Aluminum results fluctuate in ICP MS
Hi, Our analysis is by microwave digestion with 0.25g product(pectin, carrageenan, fiber etc.) in 5 mL HNO3 and 1 mL HCl. We have two calibration curves as we for some light metal have very high content but also low content. We normally see the same results with both calibrations but uses the results there is within one of the calibration curves. We have then observed for some matrixes that aluminum results fluctates alot between our directly analysed sample and when it has been diluted 10 times. e.g. when measure directly after digesten gives 8.58ppm and after a dilution factor of 10, gives 13.5ppm. A colleague sugested that Aluminum need Cl to solubolize and wee tried adding more HCl after digestion but also in the digestion. But we do not get consisten results. Can you help? or what is the best way to get aluminum solubilized? the source of aluminum can be many as it is a natural product but also get som from the production equipment.
Created: 04/06/21 07:55:39
Created By: "Louise Ottesen"
1 2439
Aluminum results fluctuate in ICP MS
Hi, Our analysis is by microwave digestion with 0.25g product(pectin, carrageenan, fiber etc.) in 5 mL HNO3 and 1 mL HCl. We have two calibration curves as we for some light metal have very high content but also low content. We normally see the same results with both calibrations but uses the results there is within one of the calibration curves. We have then observed for some matrixes that aluminum results fluctates alot between our directly analysed sample and when it has been diluted 10 times. e.g. when measure directly after digesten gives 8.58ppm and after a dilution factor of 10, gives 13.5ppm. A colleague sugested that Aluminum need Cl to solubolize and wee tried adding more HCl after digestion but also in the digestion. But we do not get consisten results. Can you help? or what is the best way to get aluminum solubilized? the source of aluminum can be many as it is a natural product but also get som from the production equipment.
Posted: 04/06/21 07:55:40
Odd aluminum results
I'm attempting to determine aluminum in a vitamin/mineral premix matrix using ICP-OES. I've been analyzing replicates in an attempt to determine the precision of my method in this matrix. I've found some odd behavior in the results. It seems like if I analyze the sample digest a short time after digestion, it gives results that are 20 percent higher for aluminum. I looked at 3 wavelengths (308, 394, 396), and they all give similar results. Analyzing the digest right after the digestion gives about 600 ppm. If I wait a few days, the results go down to around 500 ppm. I've tried two different instruments and sets of standards. I'm digesting the samples on a hot plate with about 1:6 ratio of concentrated nitric acid to concentrated hydrochloric acid. The resulting digest is clear with a light yellow color. I tried another mineral premix, and it does not have the same issue. The method I'm using is a multi-element method. It gives the same results for other elements like Co and Cu between the fresh and older digests. It's just aluminum that drops in concentration over time. I know Se and As have issues with carbon enhancement in ICP analysis, but I haven't heard anything about aluminum having issues. Does anyone know what could be causing freshly digested vitamin/mineral premix samples to give high results for aluminum?
Created: 03/19/21 16:44:09
Created By: "Josh Messerly"
5 1907
Odd aluminum results
I'm attempting to determine aluminum in a vitamin/mineral premix matrix using ICP-OES. I've been analyzing replicates in an attempt to determine the precision of my method in this matrix. I've found some odd behavior in the results. It seems like if I analyze the sample digest a short time after digestion, it gives results that are 20 percent higher for aluminum. I looked at 3 wavelengths (308, 394, 396), and they all give similar results. Analyzing the digest right after the digestion gives about 600 ppm. If I wait a few days, the results go down to around 500 ppm. I've tried two different instruments and sets of standards. I'm digesting the samples on a hot plate with about 1:6 ratio of concentrated nitric acid to concentrated hydrochloric acid. The resulting digest is clear with a light yellow color. I tried another mineral premix, and it does not have the same issue. The method I'm using is a multi-element method. It gives the same results for other elements like Co and Cu between the fresh and older digests. It's just aluminum that drops in concentration over time. I know Se and As have issues with carbon enhancement in ICP analysis, but I haven't heard anything about aluminum having issues. Does anyone know what could be causing freshly digested vitamin/mineral premix samples to give high results for aluminum?
Posted: 10/20/21 11:57:07
Calculation to convert ICP-OES Silicon results to Silica
We analyze for Silicon via ICP-OES in aqueous matrices and perform a calculation to convert the Silicon result determined from the instrument into a Silica result. I want to confirm that the calculation we are using for the conversion is accurate. Can you provide me with the calculation your experts would recommend?
Created: 11/30/20 10:56:02
Created By: "Calista Daigle"
1 5835
Calculation to convert ICP-OES Silicon results to Silica
We analyze for Silicon via ICP-OES in aqueous matrices and perform a calculation to convert the Silicon result determined from the instrument into a Silica result. I want to confirm that the calculation we are using for the conversion is accurate. Can you provide me with the calculation your experts would recommend?
Posted: 11/30/20 10:56:02
SIC for 6020 B EPA method
We are working on EPA 6020 B method development for analyzing just Ca, K, Mg, Na in the precipitation water samples. How do we modify the spectral interference check solution (SIC) given in the 6020B method to verify any isobaric interferences? Thank you.
Created: 10/19/20 15:39:24
Created By: "Rita Bargon"
1 2141
SIC for 6020 B EPA method
We are working on EPA 6020 B method development for analyzing just Ca, K, Mg, Na in the precipitation water samples. How do we modify the spectral interference check solution (SIC) given in the 6020B method to verify any isobaric interferences? Thank you.
Posted: 10/19/20 15:39:24
Concentration of Internal Standard
I have a question about the concentration of internal standard. We are using EPA 200.8 to analyze environmental water. I heard that "the concentration of Sc should be 100ppb and Y, In, and Tb is 20-30ppb.". Because we are using multi-element internal standard in ICP-MS, the concentrations of Sc, Y, In, and Tb are the same and I can't make like 100ppb Sc nad 20-30ppb others as what I heard. (1) Can you let me know why the concentration of IS should be different? (2) Please let me know why the concentration of Sc should be higher than others. Also, I heard that I have to use individual internal standard to make internal standard like below. "Sc can start at 50ppb: add 25ul to 500ml bottle or 50ul to 1L bottle. Spike in additional amounts until counts are 2.5-3.5M (guess total of 100ppb) All the other IS (Y, In, and Tb) start at 10ppb: add 5ul to 500ml bottle or 10ul to same 1L bottle. Spike in additional amounts until counts are around 500k (guessing 20-30ppb).". "This is for the optimization of internal standard." (3) Can you explain what is the optimization of internal standard, if you know? (4) Who can use the multi-element internal standard? Thanks and I am looking forward to hearing from you.
Created: 07/24/20 03:42:54
Created By: "DONG KIM"
2 3308
Concentration of Internal Standard
I have a question about the concentration of internal standard. We are using EPA 200.8 to analyze environmental water. I heard that "the concentration of Sc should be 100ppb and Y, In, and Tb is 20-30ppb.". Because we are using multi-element internal standard in ICP-MS, the concentrations of Sc, Y, In, and Tb are the same and I can't make like 100ppb Sc nad 20-30ppb others as what I heard. (1) Can you let me know why the concentration of IS should be different? (2) Please let me know why the concentration of Sc should be higher than others. Also, I heard that I have to use individual internal standard to make internal standard like below. "Sc can start at 50ppb: add 25ul to 500ml bottle or 50ul to 1L bottle. Spike in additional amounts until counts are 2.5-3.5M (guess total of 100ppb) All the other IS (Y, In, and Tb) start at 10ppb: add 5ul to 500ml bottle or 10ul to same 1L bottle. Spike in additional amounts until counts are around 500k (guessing 20-30ppb).". "This is for the optimization of internal standard." (3) Can you explain what is the optimization of internal standard, if you know? (4) Who can use the multi-element internal standard? Thanks and I am looking forward to hearing from you.
Posted: 09/28/21 13:37:17
Lithium Analysis in Brine Solutions
I've been told that Lithium analysis by ICP-OES poses problems in high brine solutions? Currently accepting requests for Li analysis in brine. Are there issues and interferences I should be concerned about?
Created: 07/16/20 14:56:23
Created By: "Andrew Skroly"
1 2162
Lithium Analysis in Brine Solutions
I've been told that Lithium analysis by ICP-OES poses problems in high brine solutions? Currently accepting requests for Li analysis in brine. Are there issues and interferences I should be concerned about?
Posted: 07/16/20 14:56:23