Low dew point membrane type air drier

Fig. 1  Conventional standard air drier built-in compressor in use.


Fig. 2  Low dew point membrane type air drier (dew point: -40℃) in use.
※ Conventional compressor is concurrently used.

Among NMR instruments, an air drier is used to generate dried gas for tempera-  ture control, sample spinning, sample loading/ejecting, and so on. In the air, some  moisture may remain depending on the drying performance, yielding unwanted  vapor signals especially in the variable temperature experiments. The air drier of  the standard configuration has sufficient capability for usual measurements to  suppress the unwanted signal at the level lower than ¹³ C satellite signals and  impurity signals of a small amount of normal solvent (less than 2%) contained in  commercial deuterated solvent (Fig. 1). However, the unwanted signals may be an  obstacle when the small signals in the vapor region are quantitatively observed. In  such cases, vapor signals can be reduced to the undetectable level, by using a low  dew point membrane air drier having higher drying capability (Fig. 2).

※ To use the low dew point membrane air drier, a high pressure compressor may separately be  required to increase gas flow.