LED-photometer

Figure 1. The manifold (top) for the determination of phosphate hy FIA. Key P, the pump (Gilson Mini Puls) IV, injection valve (Rheodyne Model 50) D, LED photometer (24) with an IR LED (880-nm maximum emission) and R, recorder. Typical results for a series of standards are shown (hottorn).

Figure 3. Partial schematic of the LED photometer electonics and flow cell designed by Betteridge et al. (24),...

The LED photometer can, therefore, be used for the determination of nitrate, silicate, phosphate, and ammonia with the analyses commonly used for these groups (2, 7). 

Fig. 10-14. CFA manifold for nitrate with LED-photometer and twin photometer amplifier (Institut fiir...

As noted earlier, on-line process monitoring is among the application areas that can benefit most from the use of sensors provided they can be incorporated into portable systems. Electrochemical sensors are generally more suitable for these applications, even though optical sensors can also be readily adapted for this purpose (e.g. by using LEDs or photodetectors instead of conventional photometers) at the expense of somewhat degraded spectral resolution and sensitivity. 

MCFIA system for speciation of inorganic nitrogen. Detector dual-color LED homemade photometer RC reaction coil V solenoid valve. 

Photometer Tungsten lamp Attenuated light beam Filter Photodiode Electrical current Amplifier, di tizer, LED display... 

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