Determination of tungsten in bulk drug substance and intermediates by ICP-AES and ICP-MS.

A quick and sensitive method has been developed and validated for the determination of tungsten in bulk drug substance and intermediates using either Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) or Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Sample preparation is by direct dissolution with a 80:20 (v/v) concentrated nitric acid:deionized water mixture and avoids labor intensive and potentially hazardous digestion techniques. Excellent agreement was found between ICP-AES and ICP-MS results and between Merck results and Microwave Induced Plasma Mass Spectrometry (MIP-MS) results provided by an independent raw material vendor.