Article ID Journal Published Year Pages File Type
1243517 Talanta 2008 4 Pages PDF
Abstract
A liquid chromatography-mass spectrometry (LC-MS) method was developed as limit test for an amine cross-linking residue in a pharmaceutical polymer. The method was based on full scan data with extracted ions for the accurate masses of dicyclohexylmethane-4, 4′-diamine (DMDA) and the internal standard 1,12-diaminododecane (DADD) obtained by Fourier transform MS. Dicyclohexylmethane-4,4-diisocyanate (DMDI) the reactive form of the cross-linking residue was determined as it decomposition product DMDA. Calibration curves for quantification of DMDA were linear in the range 2-100 ng/ml, the LOD was 1 ng/ml or 10 pg on column. Precisions/recoveries for spiked samples at the level of the limit of 1 ppm for DMDA and DMDI were ±9.6%/38.6% and ±14.5/10.0% (n = 3), respectively. Unpredictable recovery was found in the extraction of polymer samples because of the complexity of the matrix and the reactivity of dicyclohexylmethane-4,4-diisocyanate (DMDI). PEG residues extracted from the polymer were found to cause ionization suppression and also affected the chromatography, these effects were reduced by using a gradient program. By using this method the level of amine residues in samples from different batches of polymers were determined to be much lower than the limit of 1 ppm. The method allowed comparison of the results obtained from the polymer before and after purification indicating that the residual DMDA could be decreased by a washing procedure.
Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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