Hi Steven,

I use 0.1% Triton X-100 in the diluent.  The diluent is as follows:

For 50 mL

50 uL Triton X-100
1 mL 25% TMAH
50 uL of 10 ug/mL TE
48.9 mL Water

Thank you for your advise and guidance.

Best Regards,


Mukul
Mukul N. Patel
Accu Reference Medical Lab
1901 East Linden Avenue, Suite 4
Linden, NJ 07036
Mobile: (732) 599-6137
________________________________________
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [[log in to unmask]] on behalf of Pappas, Richard Steve (CDC/ONDIEH/NCEH) [[log in to unmask]]
Sent: Wednesday, March 29, 2017 3:54 PM
To: [log in to unmask]
Subject: Re: Iodine blank values too high

Unless there is a buildup of iodine in your system, I would think that serum iodine blanks should not be very high, considering that serum iodine is generally under 100 ng/mL. Though thyroid hormones (TH) are hydrophobic, they are transported bound to Thyroxine-binding globulin. That said, a very acidic or basic medium could denature the protein, allowing the TH to be released. If you are not using any detergent like Triton X-100 along with your TMAH, then hydrophobic TH could be released and stick to hydrophobic surfaces like tubing in the introduction system and continue to rinse out over a long period. That is one guess, because the details of the method were not described.

R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA


-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [mailto:[log in to unmask]] On Behalf Of Mukul N. Patel
Sent: Wednesday, March 29, 2017 2:03 PM
To: [log in to unmask]
Subject: Re: Iodine blank values too high

Steven,

Thank you.  I am trying to measure iodine in serum or plasma.  I ran about 28 diluent blanks by which time iodine intensities stabilized to 3818.7 intensities.  What kind of iodine intensities the diluent or reagent blank should one get in order to correctly measure iodine in the above sample with calibration coefficient of 0.999 or more and QCs within the expected range?

Thank you again for your advise and guidance.

Best Regards,

Mukul
Mukul N. Patel
Accu Reference Medical Lab
1901 East Linden Avenue, Suite 4
Linden, NJ 07036
Mobile: (732) 599-6137

________________________________________
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [[log in to unmask]] on behalf of Pappas, Richard Steve (CDC/ONDIEH/NCEH) [[log in to unmask]]
Sent: Wednesday, March 29, 2017 1:10 PM
To: [log in to unmask]
Subject: Re: Iodine blank values too high

There were more other replies than I could shake a stick at. I don't know if someone else answered this.
Yes, for example, in urine, sometimes Mo can be several hundred µg/L. Iodine will be much lower. I was considering the possibility that your samples, not knowing what kind you have, had very high Mo that had been incompletely rinsed out. It may not be a problem, just a thought. Mo+ can form MoO+,but Mo as molybdate should be soluble in base. Now that I know you are using TMAH, Mo should be rinsed out effectively, probably not a big contributor to blank.

R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA


-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [mailto:[log in to unmask]] On Behalf Of Mukul N. Patel
Sent: Wednesday, March 29, 2017 9:57 AM
To: [log in to unmask]
Subject: Re: Iodine blank values too high

Hi Steven,

I didn't understand by your comment about "95MOO+ if you have high molybdenum".  Do you think the high intensities are due to molybdenum contamination? Would you be kind enough to clarify.

Thank you for your consideration and help.

Best Regards,

Mukul
Mukul N. Patel
Accu Reference Medical Lab
1901 East Linden Avenue, Suite 4
Linden, NJ 07036
Mobile: (732) 599-6137



________________________________________
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [[log in to unmask]] on behalf of Pappas, Richard Steve (CDC/ONDIEH/NCEH) [[log in to unmask]]
Sent: Wednesday, March 29, 2017 9:21 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: Iodine blank values too high

95MOO+ if you have high molybdenum.

R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA

-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [mailto:[log in to unmask]] On Behalf Of Mukul N. Patel
Sent: Tuesday, March 28, 2017 5:16 PM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Iodine blank values too high

Hello,



        When I try to measure iodine using the following diluent, I get very high Iodine intensities as seen in the attached screen shot.  I shall be thankful for your advise and suggestion to bring the iodine background intensities to as low as possible in order to determine iodine conc. in calibrators, QCs and sample.


Diluent Composition:

50 mL solution contains:

50 uL Triton X-100
1 mL 25% TMAH
50 uL of 10 ug/mL Te
48.9 mL of water


    Thank you for your help and advise.



    Best Regards,



Mukul

Mukul N. Patel

Accu Reference Medical Lab

1901 East Linden Avenue, Suite 4

Linden, NJ 07036

Mobile: (732) 599-6137