Biomedical subjects

Ake Stenholm

Publications and source records attributed to Ake Stenholm.

2 recordsLinked to original sources

PubMed2006

Comparison of amine-selective properties of weak and strong cation-exchangers.

The capacity of several weak and strong cation-exchangers to adsorb 2-diethylaminoethanol (DEAE) and (2,3-hydroxypropyl) trimethylammonium chloride (HPMAC) from sodium-containing process water streams, and the ease of subsequently eluting the amines and regenerating the exchangers, were investigated. (2,3-hydroxypropyl) trimethylammonium chloride was enriched 40-fold compared with the initial amine/sodium-ratio in the bulk fluid by Amberlite IRC-50. The highest selectivity for 2-diethylaminoethanol (26-fold) was provided by Imac HP336. Neither of the selected strong cation-exchangers showed any selectivity towards 2-diethylaminoethanol, but they enriched (2,3-hydroxypropyl) trimethylammonium chloride approximately three to four fold. These findings suggest that weak cation-exchangers (WCX) could be readily used for the selective removal of these or similar amines from sodium-containing process waters.

Adsorption↗

PubMed2005

Development of a solid-phase extraction/gas chromatographic-mass spectrometric method for quantification of succinic acid in nucleoside derivatives for oligonucleotide synthesis.

A solid-phase extraction (SPE)/gas chromatographic-mass spectrometric (GC-MS) method was developed for analysing residual succinic acid in nucleoside derivatives to be used in oligonucleotide synthesis. Use of a SPE protocol, enabled most of the derivatives to be trapped, thereby creating eluates enriched in succinic acid. GC-MS was used to quantify the amount of residual succinic acid in four different nucleoside preparations, with succinate concentrations varying from 0.18 to 0.24% (w/w). The within-day repeatability of the method was found to be 1.25% RSD. A linear relationship was observed between the amount of succinic acid in the sample and the GC-MS peak area, with a correlation coefficient of 0.9997 in the concentration interval 0.05-2.5% (w/w). Recoveries were measured by the addition of internal standards to working solutions and varied between 99.8 and 102.6%.

Chromatography, Liquid↗