Use of a laboratory robot for repetitive solution NMR sample preparation

Abstract

Observing ligand 1H NMR signals while conditions (e.g., analytical concentrations, pH) are changed in an aqueous metal–proton–ligand system is one of the most potent methods of elucidating the precise details of speciation in such systems. Typically this is performed by changing the conditions in a solution reservoir, while withdrawing a sample for NMR analysis at each stage. However, such sample preparation is tedious and time-consuming. We report here studies, using a Mitsubishi RM-101 laboratory robot, of the feasibility of completely automating such a procedure. A simple acid–base study is used to evaluate performance.