Fast CE for combinatorial catalysis

Abstract

Two solvent-modified MEKC methods were developed for the quantitative analysis of heterocyclic amines synthesised using intramolecular ring closure via catalysed hydroamination. The first method was capable of resolving six of the amines (precursors and products) with a sample-to-sample injection time of 2 min employing a 20 mM borate buffer, pH 9.2 with 20 mM SDS and 5% v/v n-butanol (n-BuOH). A second low-pH method using 20 mM phosphate buffer, 100 mm SDS, 5% v/v n-BuOH and 20% v/v iso-propanol (i-PrOH) was able to resolve an additional pair of compounds with a sample-to-sample time of 3.5 min. Application of the first method to the analysis of a sample containing catalyst as well as amines placed directly in a 96-well plate showed excellent performance, with migration time and peak height and area reproducibility being less than 0.9 and 9.6%, respectively. The quantity of conversion by catalyst was calculated to be 68 +/- 7%, which was in excellent agreement with the 67 +/- 5% obtained by more conventional (1)H NMR experiments, with the added advantage that this method is also cheaper, quicker and more amendable to high-throughput screening of combinatorial libraries.

Time as a Dimension in High‐Throughput Homogeneous Catalysis

“…Emerging methods for multiplexed GC can handle up to 450 samples/h. [21] Comparably impressive throughput has been described in flow NMR [22,23] and capillary electrophoresis [24,25] in enantioselectivity determination.…”

The Future, Faster: Roles for High-Throughput Experimentation in Accelerating Discovery in Organometallic Chemistry and Catalysis

“…Emerging methods for multiplexed GC, which can currently handle up to 450 samples/h, offer a powerful way to cope with this challenge. Comparably impressive throughput has been described for capillary electrophoresis methods, albeit predominantly for relative assessment of enantioselectivities rather than absolute quantitation. , A general limitation to the use of off-line analytical methods, however, is the need to terminate all reactions in the entire plate at a single, arbitrary reaction time, prior to analysis.…”