Fast Temperature Programs For LC

A team of researchers at Dow Chemical has developed low thermal mass liquid chromatography, a method that enables rapid heating and cooling of the chromatographic system (Anal. Chem., DOI: 10.1021/ac802022z). Similar methods have been used for gas chromatography, but Hernan Cortes and coworkers now extend the concept to LC. Their system consists of a capillary LC column threaded through a temperature control module that uses resistive wire heating. The heating module generates temperature gradients as large as 1,800 °C per minute. The researchers use the system for fast temperature programs with isocratic and solvent-gradient separations of various mixtures. For example, a mixture of neutral and acidic compounds can be separated in less than a minute by using a temperature gradient of 100 °C per minute. In addition, the system’s heating and cooling capabilities mean that oscillating temperature gradients can be used to fine-tune LC separations, especially for mixtures containing what normally are coeluting basic compounds.