Method and apparatus for the analytical determination of soluble constituents in fibre materials as traeger media

摘要

1522965 Chemical spot test photometry; chemical spot test DAMON CORP 15 Aug 1975 [19 Aug 1974] 34011/75 Headings G1A and G1B A chemical spot test apparatus comprises a porous or fibrous medium with sample and reagents at a site therein, in optically thin concentrations, means of producing an incident beam of electromagnetic radiation, the resulting emergent radiation having a parameter which changes with concentration of a reaction component and means for detecting the parameter providing a measure of change in this concentration. Optically this is defined by the absorbance of electromagnetic radiation by the concentration being measured being less than 0À2. The embodiment of Fig. 4 comprises fluorimeter 30 and press 32. The sample is deposited on dry fibrous sheet 36 by pipette 40. When press head 51 is lowered it forces some of the small molecule fraction through ultrafiltration membrane 38 to dry fibrous reagent bearing sheet 34. Base 42 has passages 48 and 50 making equal angles with sheet 34, of which the part under foot member 52 is illuminated by lamp 44 through filter 54 and platten 46. These are reference detector 56, fluorescence detector 58, lens 60 and filters 62, 64, 66 of low fluorescence. The embodiment of Fig. 6 (not shown) has a continuous paper strip carrier (72) resting on a flat surface. A transparent film (76) is wrapped around it to enclose the reactants and prevent evaporation. A heating element (92) prevents condensation. Photometers other than fluorimetric may be used instead. In the embodiment of Fig. 7 (not shown), the carrier (102) is located between lower (96) and upper (108) housings which both have light passages. Thus both fluorescence and absorption can be measured. The reactant bearing disc (94) is in an enclosure sealed by windows (104 and 98) and gasket (100). The reaction site may be an unbounded portion of a fibrous or porous medium. Non wicking cellulose fibres are preferred. The site is pre-treated with high molecular weight crystalline ethylene polymer. The reagents are applied in a sequence corresponding to molecular size in a repeatable spatial distribution and not saturating the site. The reaction product concentration is obtained from the difference of measurements at two times or measurements are taken at intervals. The termination of spreading occurs prior to the completion of sensing and the linear rate of change is measured. A repeatable state of compression is maintained.