High Selenium recovery in tap water

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skgndri
skgndri's picture
High Selenium recovery in tap water

We are observing a very high recovery of selenium in tap water . Kindly help.

Jruckle
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I can not open your file. 

I can not open your file.  Can you give more information about your problem.

skgndri
skgndri's picture
0.045 ml of 1 ppm selenium

0.045 ml of 1 ppm selenium stock was spiked in 10 ml tap water and samples were analyzed on ICP MS ELAN 9000.
Instrument was calibrated with 5 and 50 ppb standards. All samples and standards were having 0.2 ml of suprapur HNO3. Yettrium was added as internal standard. THe recovery found was 172 % in tap water samples. However, it was good in distilled water. Kindly suggest.
Samples were not digested.

Jruckle
Jruckle's picture
What mass are you using for

What mass are you using for selenium.  Kr in the argon can interfer with seleneum.  I have in the past had bad argon and if I tracked the Kr 83 mass it would start out with low counts and then after about an hour the counts would shoot up about ten fold.   This whould cause my Se to also shoot up.  Hope this helps.

skgndri
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We are checking mass 82 with

We are checking mass 82 with a correction equation given for krypton ( APHA 21st edition) C82-(1.008696*C83)

Jruckle
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What else are you seeing in

What else are you seeing in the samples?  You could be getting a Zinc oxide interference if zinc is high?  Sorry I cant think of any thing else.

Jruckle
Jruckle's picture
What else are you seeing in

What else are you seeing in the samples?  You could be getting a Zinc oxide interference if zinc is high?  Sorry I cant think of any thing else.

Sven1982
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Se-82 is prone to

Se-82 is prone to interferences from ArCa (40+42 and 38+44)