Sb on ICP-MS

I have experienced this problem using this matrix in 1000ppm. I have solved that when I used Sb stock std in 5% HNO3 and 1% HF matrix. Otherwise, you need to prepare specific reagent(refer to rinsing protocol for sticky element) to deal with the memory effect of Sb.

If you choose 1%HF, you will need to make sure you are using the PFA inert sample introduction setup.  1%HF will dissolve the quartz front end.  Sb can also be stabilized using trace tartaric acid (0.1%v/v) in 1%HNO3.

What instrument are you running?  What plasma parameters:  Low Matrix; General Purpose; HMI?  Sb has a high ionization potential, so 0.5 ug/L may be too low of a standard to try to calibrate on if running on a single quad (7800, 7850, 7900) using something other than low matrix settings.

Have you checked your micropipette at the volumes delivered?  pipette that amount onto a balance and make sure the mass delivered is what you would expect (1mL should read 1g or very close, 100uL should read 100ug...)  I don't know how much volume you are making the standard, but a small error from the micro pipette could introduce a large error in concentration.  I would not trust a 1/2000 dilution as much as I would a 1/20.  Try making the 0.5ug/L (0.0005ug/mL) from a 10ug/L solution not the 1ug/mL intermediate.

I am experiencing a similar issue with Sb. The calibration isn't linear, and the quality checks throughout the run show poor recovery rates, with values below 80%. When analyzing client samples and CRMs, the results from the Agilent consistently show a bias of about 5% lower compared to the ELAN 9000.

The stock solution used for calibration standards and quality check solutions is a multielement solution containing 100 ppm Sb, along with other elements, in a matrix of 7% HNO3 and 1.2% HF. The calibration standards are prepared at concentrations of 50ppb and 500ppb in a 5% HNO3 solution. For quality checks, I use a set of three standards (100 ppb, 1 ppm, and 10 ppm) also in 5% HNO3. The other elements in the stock solution do not exhibit the same behaviour as antimony.

I am running an Agilent 7900 with plasma parameters set to High Matrix.

Additionally, I have verified the pipettors and confirmed accurate sample delivery, so the issue does not appear to be related to standard preparation.

Sometimes weird recoveries are found due to bad or wared out sample introduction parts. Tubing, glassware and for example probe rinse station could cause this behavior. If the issue wasn't present before and old sample introduction parts are used please use new. Change autosampler probe and all new tubbing till the nebulizer. maybe washing with a strong detergent, without plasma on and rinse with upw water could sometimes helping getting beter recoveries.   

It does not look like you are stabilizing your standards with the HF like the stock 100ppm Sb solution.  Do you run internal standard?  Which mass are you using to correct for Sb?

Hi Tom,

Unfortunately, we cannot spike our standards with HF for safety rules on site. 

I am using Rh 103 to correct Sb.