why does Zinc 66 have very high count reading in the blank


we are developing an impurity method to detect the content of zinc. we found the zinc 66 reading is so high in the blank that even the signals in the standard solutions have no big difference from the blank. 

we used water for injection (sterile from BAXTER) to prepare blank and standard solutions. 

the questions are: 

1. does zinc 66 usually have high counts in water which is not Milli  Q? 

2. how to reduce Zinc background in blank ? 

Thank  you 

  • Zinc is a very common lab contaminant - trace amounts are in gloves, vials, pipette tips, peripump tubing, Kim wipes etc so clean prep and materials become essential.

    For low level zinc analysis a good starting point is to prewash all sample vials. I like to fill any prep vials with 1-2% HNO3, let them sit for a day or two, rinse well and fill with DI water and then cap. When ready to use empty the water and use.

    Make sure your pipette tips are specific to trace metals analysis. You can also prewash pipette tips too if you find just doing the vials isn’t enough. 

    Also make sure you are using ultra trace acid.

  • Hi Cheltajc, 

    Thank you for telling us this information. They are quite helpful. I will do this before proceeding the next step. 

    Best regards, 

    Di Xu

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