The current USP standard method <231> for determining "heavy metals" in pharmaceutical ingredients and products involves precipitating metal sulphides out of an aqueous solution, then visually comparing the colour of the test sample with that of a standard lead solution.
Although still widely accepted and used in the pharmaceutical industry, these methods based on the intensity of the colour of sulphide precipitation are increasingly viewed to be non-specific, insensitive, time-consuming, labour intensive and do not provide an 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 Emission Spectroscopy (ICP).
The new ICP method 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 sample for an additional 21 elements.
Operating in an ISO 17025 and GMP compliant environment following strict operating procedures ensures Warwick Analytical Service delivers top quality ICP data consistently. Equipped with modern high resolution ICP instrumentation - Warwick Analytical Service is able to resolve the most complex spectra and analyse even the most difficult samples. Routine detection limits are low for most elements (typically <10ppb) and multi-element determinations can be achieved rapidly and precisely.
