Applied universal design weight

This detector was invented by Martin and James (1) and is a universal detector. The design was simplified and subsequently made available by the Gow-Mac Instrument Company. Use of two of these detectors in a dual column mode is the basis for the direct determination of molecular weight (the mass chromatograph). The hydrodynamics of the gas density detector as they apply to the mass chromatograph have been studied (36). 

Recently, a universal separator has been developed which can be applied for aqueous and organic solvents at temperatures up to 140 °C [368]. This instrument is a specially designed Fl-FFF channel operating in an oven. Here, a PET ultrafiltration membrane with a high molar weight cut off of 30000 g/mol was applied. Solvents which were reported to be applicable were water, toluene, xylene, heptane, cyclohexane and THF. 

The force measuring head, together with provision for applying the extra compression. can be a beam balance, as used in the well-known Lucas apparatu.s. a universal tensile machine, or a specially designed electronic load cell unit [4]. The point at which the small amount of extra compression has been applied can be detected by breaking an electrical circuit. An early apparatus used a load cell attached to an arbor pre,ss. The operator manually lowered the pre.ss until the break in the electrical circuit was indicated visually by the extinction of a light. The Lucas apparatus has a similar detection system the balance weights are adjusted manually until the force exerted by the beam just overcomes the force exerted by the test piece. Both of these approaches involve a somewhat... 

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