Degasys Ultimate,Degasys Populaire & Degasys Features

How to Select the Suitable Model

Step 1. Select models which accord with the maximum flow rate to be applied.

NB: The maximum flow rate capacity of the degasser should be as small as possible to prevent the liquid from penetrating out through the degassing tubing membrane. If the liquid penetrated out though the degassing tubing is large, it may cause defect such as a malfunction on the vacuum performance as the valve and the valve seat will tend to stick together.

Step 2. Select the degasser series:

Inorganic solvents only:	Degasys Populaire (DP)
Organic solvents only:	Degasys Ultimate (DU)
Mixed:	Degasys Populaire and Degasys Ultimate

The above selection is based on the difference of the degassing tubing material between DU and DP:

Teflon AF (used in DU): While the Teflon AF performs well in gas penetration, the penetration of the liquid is also higher owing to the less selectivity of gas and liquid. It is suitable for solvents with larger dissolved gas content such as organic solvents.

PTFE (used in DP): The PTFE performs well in selecting gas and liquid, however, it is lower in gas penetration performance. It is suitable to use for solvents with lower dissolved gas content such as inorganic solvents.

The specifications of each model are shown in our web site under:
2007.4.26

Why are stand-alone degassers required ?

LIQUID CHROMATOGRAPHY :

All liquids contain dissolved gases which are readily absorbed from the air. In solvents for liquid chromatography, dissolved gases reduce pump flow rate stability, detector baseline stability, and increase detector noise. In low pressure gradient formation, dissolved air often outgases, causing malfunctions of the pump and associated valves. High precision constant-pressure pumping is very difficult to achieve with liquids rich in dissolved gases.

Additionally, as sample volumes continue to decrease, and detection sensitivities continue to increase, the gas components present in liquid eluents and samples have become recognized as a factor influencing analytical results. Dissolved gases affect refractive index, fluorescence, electrochemical, and ultraviolet detectors, producing spurious analytical results.

PRECISION ANALYZERS :

In precision analyzers which require precise control of fluid flow rates, such as clinical diagnostic analyzers, dissolved gases in reagents, water, and other liquids reduce the accuracy and precision of the analyzer. Typically, the performance of the pump cannot be optimized unlesss the fluids being pumped are thoroughly degassed.

HOW DEGASSING WORKS :

The degassing unit is conventionally placed in-line between the solvent reservoir and the inlet of the pump. The action of the pump draws the liquid from the reservoir through the degassing unit. Solvent is drawn through the specially formulated fluororesin membranous tubing.
The fluororesin tubing is permeable to the small dissolved gases ; hence, gases will permeate out by vacuum through the tubing. The solvent will be thoroughly degassed when it has reached the exit(s) of the degassing unit, and then will enter the pump.
Generally, the efficiency of the degassing is directly related to the internal surfaces of fluororesin tubing encased in the independent vacuum chambers and inversely related to the liquid flow rate.

(P1) (P2) : PUMPS (PS) : PRESSURE SENSOR (V1) (V2) : SOLENOID VALVES (VP) : VACUUM PUMP A : SOLVENT B : DEGASSING TUBING C : INDEPENDENT VACUUM CHAMBERS D : VALVE E : PENETRATION MEMBRANOUS TUBE F : CONTROLLER

The membranous tubes are encased in INDEPENDENT VACUUM CHAMBERS to avoid mutual interference.
SOLENOID VALVE 1 will alternatively exhaust gases in VACUUM CHAMBERS and take in the atmosphere, thereby keeping VACUUM PUMP clean. This function of SOLENOID VALVE 1 prevent VACUUM PUMP from deteriorating its degassing speeds as well as the service life.
SOLENOID VALVE 2 will open VACUUM CHAMBERS when POWER SWITCH is turned off, thereby helping minimize the changes in the mixed ratio of solvents.
PENETRATION MEMBRANOUS TUBE, providing air-curtain by air penetration, will prevent PRESSURE SENSOR from deteriorating, and at the same time maintains the service life of VACUUM PUMP by exhausting the gas inside VACUUM CHAMBERS after the gas is diluted with air entering through PENETRATION MEMBRANOUS TUBE.
The mechanism contained in the degassing instruments, Degasys, Degasys Populaire and Degasys Ultimate are patented in the U.S.A., Germany and Japan.
The specifications are subject to change without a prior notice for improvement.

The smallest internal volumes ever

The smallest possible internal volumes are quite beneficial not only to chromatograms, e.g. to obtain better reproducibility, but to chromatographers who use rather expensive solvents, as when changing from one solvent to another all the lines have to be thoroughly flushed. Degasys Ultimate uses amorphos fluoropolymer menbranous tubing which is endowed with gas diffusion rates of 200 - 300 times that of PTFE tubing. This enhanced gas transport rates provide faster degassing response times with much shorter lengths of tubing, resultant at the unsurpassed smallest internal volumes of 200 ul, 350 ul, 500 ul, and 650 ul/channel at respective maximum flow rates of 1 ml, 3 ml, 7 ml and 10 ml / minute / channel with the number of channel from one through eight.

Why is on-line degassing required and How Does It Work ?

. . . . . even through degassing modules are built in your HPLC systems

Despite the wide range of flow rates available from the pumps built in HPLC systems, most of the degassing module currently built in the HPLC systems are limited in their maximum flow rates to 7 - 10 ml/minute approximately. Even when the pump is run at a flow rate of 0.01 ml/minute(a) or 15 ml/minute(b) , the maximum flow rates specified in the degassing modules in your HPLC systems will be approximately 7 - 10 ml/minute in most cases.

This(a) will result at the most undesirable relation of a very low flow rate versus a very large internal volume, which will not only contribute to poor reproducibility but to prolonged displacement time of solvents. Air bubbles(b) will generate owing to too strong suction force applied with the pump. This is why we offer an unparalleled number of 77 standardized models to cope with each and every of diversified applications.

With Degasys Ultimate (DU) , Degasys Populaire (DP) and Degasys (DG) series, currently available are the maximum flow rates of 0.5 ml, 1 ml, 3 ml, 7 ml, 10 ml, 15 ml or 50 ml/minute, with the number of channel selectable from one through eight.

	DU	DP	DG	Built-In Module
0.5 - ml/min			0.5 ml/min/ch I.V. 1 ml
	1 ml/min/ch I.V. 200 ul	1 ml/min/ch I.V. 800 ul
	3 ml/min/ch I.V. 350 ul	3 ml/min/ch I.V. 2.5 ml	3 ml/min/ch I.V. 3 ml
	7 ml/min/ch I.V. 500 ul		7 ml/min/ch I.V. 10 ml
	10 ml/min/ch I.V. 650 ul	10 ml/min/ch I.V. 7.2 ml.		10 ml/min/ch I.V. 7.2 ml.
			15 ml/min/ch I.V. 18 ml
50 - ml/min			50 ml/min/ch I.V. 55 ml
			ON REQUEST

The I.V.*'s [Internal Volumes] indicated above are the maximum volumes at respective flow rates per channel.