USP<231> Heavy Metals Testing Changes

Determination of heavy metals in drug articles

The current USP method for heavy metals Pb, Hg, Bi, As, Sb, Sn, Cd, Ag, Cu and Mo (USP<231>) has its limitations as it is not specific or sensitive enough also it does not provide the adequate recovery of the elements being tested.

Because of these limitations the USP have proposed to replace the USP <231> heavy metals test by a method using Inductively Coupled Plasma (ICP). The ICP will test for Al, Sb, As, Be, B, Cd, Cr, Co, Cu, In, Ir, Fe, Pb, Li, Mg, Mn, Hg, Mo, Ni, Os, Pd, Pt, Rh, Rb, Ru, Se, Sr, Tl, Sn, W and Zn.

The proposed revision will eliminate the specificity issue, provide greater sensitivity down to part-per-billion (ppb) levels and will evaluate the drug article for an additional 21 elements.

Butterworth Laboratories have extensive experience in determining these and other metals by ICP-OES and have historically offered this technique when dealing with materials failing the current colorimetric test.

If you require further information please contact:

David Riches, Analytical Operations Manager (david.riches@butterworth-labs.co.uk)
Martin Boyle, Senior Analytical Chemist (martin.boyle@butterworth-labs.co.uk)

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