Detector room choice

For the conventional refractive index detector, the choice of solvent depends on three main factors (i) solubility of the sample (ii) compatibility with the column packing and (iii) compatibility with the detector. Samples of low molecular mass generally are soluble in a wide range of solvents. As the molecular mass increases, there may be a decrease in solubility. Thus paraffin waxes are freely soluble in THF at room temperature, but microcrystalline waxes require elevated temperatures for complete dissolution. 

Q, FKM, and EPDM are examples. An example of SEC analysis of these rubbers is seen in phosphazene rubbers (30,31). In the SEC of such rubbers, difficulties arise in finding suitable SEC solvents. In principle, such methods as increasing the temperature to enhance the solubility are needed for these rubbers. In EPDM or EPM (copolymers of ethylene and propylene), for instance, once normal room temperature SEC was used, but today use of a high-temperature SEC is the most common because these may contain some crystalline parts depending on the block of Cj or C3 segments. Choice of other solvents depends on the required sensitivity of the detectors. 

From the point of view of the D f parameter, not taking into account the other criteria, photonic detectors appear as a better choice. To be sure, microsystem technologies enable a simultaneous increase of both the speed and the detectivity of thermal detectors, but only up to a certain point. According to [6], not only that the maximum specific detectivity and the bandwidth of these devices are inversely proportional, but also the maximum attainable specific detectivity at room temperature is limited by integral radiation of the background, not only by its part covered by spectral sensitivity range of the detector, as is the case with photonic devices. The conclusion is that a photonic detector without cooling requirements would have a chance to approach nearer to the idealized device described in Sect. 1.3. 

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