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The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including by researchers from the Department of Computer & Information Sciences involved in mathematically structured programming, similarity and metric search, computer security, software systems, combinatronics and digital health.

The Department also includes the iSchool Research Group, which performs leading research into socio-technical phenomena and topics such as information retrieval and information seeking behaviour.


Determination of cross-linking residues in a pharmaceutical polymer by liquid chromatography-high resolution full scan mass spectrometry

Zhang, T. and Watson, D.G. and Lu, D. and Carr, D. and Trager, L. (2008) Determination of cross-linking residues in a pharmaceutical polymer by liquid chromatography-high resolution full scan mass spectrometry. Talanta, 76 (3). pp. 509-512. ISSN 0039-9140

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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.