Boron analysis by ICP-MS

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KevinTu's picture
Boron analysis by ICP-MS

Hello, nice to meet you all!
I need to analyse boron at around 4 ppb in drinking water matrix by Agilent ICP-MS 7500ce. This machine was used to test boron at hundreds ppb levels before, but there is no available data for background boron. When I checked for background, cps for boron in 2% HNO3 is ~ 90K. I wonder if this is the 'normal' boron background, and anyway to eliminate it?

Some B-contamination sources that I suspected are spray chamber, torch (quartz), and the glass bottle containing supra pur HNO3 65%. Does it make sense, or are there other contamination sources?

For a 2% HNO3 solution (blank), the boron cps appeared in the tunning window (~100K) was much lower than which appeared in the acquired sequence (~600K) with the same operational and acquisition parameters. Any explaination for this?

I greatly appreaciate for you response. I am stucked!!!

faridr1's picture
You know I have no experience

You know I have no experience with Agilant instrument. The only thing that I could say is to stay away from and borosilicate glassware which we are usually using it.

Use plastic/nalgene volumetric flas or bottles for all standard preparations. You may use other type of spray chamber which is not made by glass such as Ryton spray chamber if available by Agilant. Use Alumina injector and I have no idea about torch but it might be OK. You may want to look into their cataloge and find out whether the torch is made by borosilicate .

Good luck.

orionps's picture
Everytime I have had high

Everytime I have had high Boron in my blanks, it is an indication that its time to change the filter on the Reverse Osmosis system.  You might want to look into that as well.

KevinTu's picture
Thanks faridr for your reply.

Thanks faridr for your reply.
I am aware and have not been using any glassware for sample preparation. Assuming that we can avoid machine's glassware components, there is still a major source of boron contamination. Remember that the 'supra pur' acid that we purchased from all suppliers is contained in a borosilicate bottle. We use this acid, although diluted, for all ICP-MS works. This is a 'funny' paradox. Some articles said boron leached out from borosilicate glassware can be around 200 ppb.

Do you or anyone know any supplier provides acid in other container materials? Please let me know, great appreacition.

Sven1982's picture
Each supplier of high-purity

Each supplier of high-purity acids will have a product line in that type of container.

For instance:
SCP Science: Plasmapure plus
Merck: Ultrapur

riverbrat's picture
I agree that a major source

I agree that a major source of boron contamination is a polishing tank that needs recharged,  We analyze boron with an mdl of 3 ppb our low standard is 5ppb. The only time we have problems is when our water is contaminated from the tanks. I have not found any problematic contamination from bottles or spray chambers. Try concentrating your di...digesting it down to a low volume and then bringing it back to original volume with DI...if your boron counts go up, I would consider your tanks as the source.

ToxLabRat's picture
I am in agreement with

I am in agreement with Riverbrat and Orionps, it sounds like it is time to change the filter packs in your water polishing system.  You should be using ASTM Type I water, therefore you probably have a DI or RO system that feeds into a secondary polishing system (I.e. Millipore Academic).  That secondary polishing system should have a place where you can measure the resistivity, so I would check to see that the measurement on your system is 18.2 megaohms.  If it is not then that is a sure sign that you need to replace the packs.  If it does read 18.2, then it might be worth taking a look at the Certificates of Analysis that accompany each lot of the trace metal grade acids and reagents that you use.  Not all trace metal grade reagnets and acids are created equally, and I have seen many brands that call their material trace metal grade but when I reviewed the CofA the results for some of the analytes were far too elevated for use in my applications (which is analysis of water, wastewater, groundwater, soil and sludge samples).

Its not a bad idea to store your intermediate reagents in FEP bottles if you are not already doing so, because they are inert and therefore trace contaminants do not leach out of the container and into your reagent.  These bottles are expensive but they last for ages.