[anil2203]

HOW TO DERTRMINE IRON/VANADIUM and other metal impurities in TiO2??

[mer-mer-mer-mer-mer]

You can analyze it with ICP-OES

[marquis]

With great difficulty.

Titanium dioxide is only soluble in strong acids.  The USP uses is hot sulfuric acid.  While it is possible to use a technique like AA or ICP with this matrix, it is not easy.  You also must take suitable precautions.

In this situation, EDXRF (energy dispersive x-ray flourescence) might be a better approach.  The acid digestion would not be needed.  While detection is rather simple, calculation of concentration can be interesting.

Good luck...

[anil2203]

Thanks for Reply.

[mer-mer-mer-mer-mer]

With great difficulty.

Titanium dioxide is only soluble in strong acids.  The USP uses is hot sulfuric acid.  While it is possible to use a technique like AA or ICP with this matrix, it is not easy.  You also must take suitable precautions.

In this situation, EDXRF (energy dispersive x-ray flourescence) might be a better approach.  The acid digestion would not be needed.  While detection is rather simple, calculation of concentration can be interesting.

Good luck...

EDXRF may not require acid digestion, but non-destructive analysis presents several problems. Repeat analysis of the sample is challenging unless the target analytes are homogeneous throughout the sample matrix. Particle size and sample density also affect the analysis. X-ray absorption/enhancement phenomena can also alter the results while you can analyze IEC factors with ICP to compensate for spectral interference.

.

[marquis]

There is no method that is perfect.  It often boils down to the equipment you have on hand.

With EDXRF there can be particle size problems.  We handled particle size effects by embedding the titanium dioxide in a suitable matrix-usually wax or plastic.

And the calibration curves can be interesting.  Most people expect a Beers-Lambert type curve.  As you alluded to, the shape of the curves can often be different from a typical Beers Lambert curve.

To me, this is offset by the advantage of not having to handle digestion in strong acids.  I don't have ICP, only AA.  The special nebulizers and reagents needed for AA aren't worth it to me.

As usual, each chemist has to weigh the advantages and disadvantages (usually instrument cost or instruments on hand, analysis time, and reagent cost) to make an informed decision.