ABSTRACT
Temperature is a variable that affects sample stability, chromatographic resolution, and detection. Control of temperature at each step, therefore, is essential in high-performance liquid chromatography (HPLC). The advent of automatic injection has meant that samples are often stored in solution for periods of hours to days awaiting injection, as is discussed in Chapter 16. Many samples are stable indefinitely; however, some samples, particularly those of biological origin, are highly labile. For example, proteins decompose by hydrolysis of amides, by oxidation of residues, such as cysteine and methionine, and by aggregation [1]. Even simple synthetic compounds can decompose while waiting for injection. Accordingly, testing sample stability is essential to HPLC method development. Because sample stability is a very extended topic, this section will instead focus on temperature effects on retention, efficiency, detection, and other parameters of system performance. Control of these parameters ensures optimal HPLC performance. Devices for control of temperature will also be described.
