No.2 Temperature control of the refractive index detector

Although UV detectors are most commonly used in HPLC, refractive detectors are used when analyzing a compounds without a UV absorption band such as sugars. When conducting sugar analysis using a refractive detector, baseline instability will generally become a problem. Probably most of the baseline drift problems are due to the changes in temperature of a column. Comparison of baseline stability by a difference of a control method of column temperature is shown in the figures below. Baseline drift is very high at an ambient temperature without any column temperature control. Even in the case of a water bath or a column oven, baseline noise may occur by the change of temperature as a result of ON/OFF of a heater. As a measure to avoid this, placing the column in a water bath at the ambient temperature and stirring without heating can produce the desired effect.