General Spectroscopy

We normally analyse rubidium (Rb) using our flame AAS but that broke down a couple down a couple of weeks ago and it looks like it will be offline for a while yet. So I'm trying to develop a method for rubidium analysis using ICP-OES. However, I'm finding that the results of the samples and QCs that I've run are significantly higher than the results that were produced previously on the AAS. I was told by the AAS technician that potassium is dosed into the calibration standards as an ionisation suppressant. So I'm wondering if I need to do this as well with my calibration standards? And is there anything else that I should consider that will make this method feasible?The samples that we analysing are predominantly brines from geothermal power stations. We do have an ICP-MS and the method development that I have done for rubidium analysis has been very successful. However, I have to dilute the samples 1000x in order to dilute out the sodium and silica, but this dilutes the rubidium to roughly 1ppb. So ideally I would prefer to use a method on the ICP-OES so that I can run the samples without any dilution.

As of December 2015, USP 232 is now official. What is your timeline to update the USP multi-element standards (IV-STOCK-38 and IV-STOCK-39)?

Can you tell me if you can analyze for Lithium in samples by analyzing for Lithium 7 while using Lithium 6 in an internal standard mix?

Can your stock product IV-ICPMS-71A be used in ICP-OES analyses, or is it only for ICP-MS?

I just wanted to ask why is it preferred to use 2-5% of nitric acid solution as a matrix instead of 1%. My application is regards measuring groundwater samples. My calibration curve came out beautifully using 2% HNO3, and I just wanted to understand why you did not advise using a 1% solution.

Can you please help us locate a solid standard reference material (SRM) to validate data? We have a request to analyze an SRM solid matrix in addition to samples via ICP-MS, using the prep method 3050B and analyzed using method 6020. Is this a product that you offer?

Is the CGCR(3)1 standard free of Cr VI, and if not what is the concentration of Cr(VI)?

We have just bought a ICP instrument and are trying to get it certified. My question for you is regarding your Method 200.7 Interference Check standards. If you would compare EPA Method 200.7, section 7.13.1, where the interference check standard is specified, with your 200.7 Interference Checks, you will see two major differences: There concentrations are all different with or without dilutions. E.g., Al 200ppm (200.7) vs. 3,000ppm (IV 2007ICS-4), Fe 300ppm (200.7) vs. 12,500ppm (IV 2007ICS-4) You deleted Ce, but added B, Sb, Ag, As, K, Pb, Se, Zn, CA, Mg, and Na. I am pretty sure you have good reasons to do so, but would like to hear about them.

What is the best way to clean quartz flasks that have been used to digest organic compounds? Currently, our glassware is typically soaked for about 24 hours in 25% v/v nitric acid in a plastic container, then rinsed in distilled water.

Which results tend to be more accurate for metals in concrete: XRF or ICP? I use ICP and ICP-MS and often compared my data to other analysts' XRF values and they never agree. For XRF, our lab usually does a borate powder press then performs a standardless analysis.