Light transmission through membrane

Figure 3. Light transmission through flow cell (no membrane in place) during wash-in and wash-out of a blue dextran solution at 2.24 mL/min.

Figure 4. Light transmission through a 0.307 mm-thick pAAm/GO/PR membrane with internal Dacron mesh and 25 mg/mL glucose oxidase, as a function of time for changes in glucose concentration from 0-10 mg% (lower curve) and 10-20 mg% (upper curve). Flowrate of buffer was 2.0 mL/min.

IR radiation is emitted from the electrically modulated light source. The analytically relevant spectral range is transmitted through an interference filter, the sample chamber, and the membrane. This radiation is focused on a thermal detector (Dl), pyroelectrical or thermopile. The reflected radiation from the filter is used as a reference (D2). A comparison of the ATR-, the fiber-, and the transmission-method. Secs. 6.5.2.1, 6.5.4.2, and 6.5.4.4, shows that the ATR method is most versatile for all applications and that the transmission method allows the lowest limit of detection for gases (Hadziladzaru, 1994). The properties of the ATR method by employing wavelength selection with tunable interference filters has been studied by Lebioda (1994). 

In the experimental setup (Fig. 1) the sample (membrane of PAA) and the detector can turn aroimd the axis passing through the sample plane. Such scheme permits to make experiments on light scattering by a sample at different angles of laser beam incidence as well as experiments on transmission diagrams investigation. 

---