1. Autosampler as a substitute for a multi-way valve

As the FIA valve system is very difficult for the hobbyist to reproduce, I decided to replace the valve with an autosampler. An autosampler is commonly a device that is coupled to an analytical instrument providing samples periodically for analysis.

Fig. 1 .1 Autosampler under construction.

Fig. 1.2 3D printed probe rack.

Fig. 1.3 The peristaltic pump that I use. The tubing is easy to replace and the stepper motor ensures a precise flow rate.

Fig. 1.4 Laser cut-back panel. I am using a CNC Shield V3 to control the steppers.

Demonstration of the finished autosampler:

Fig. 1.5 Wiring diagram of the CNC shield V3.

2. Rest of the flow injection analyzer

A so-called mixing coil is required to mix the reagent with the sample. I 3-D printed this in ABS.

Fig. 2.1 Mixing coil

Fig. 2.2 Mixing coil with silicone tubing

A 3-way valve made of glass serves as the injection valve.

Fig. 2.3 Three-way valve often used in chemistry

The 3-way valve is actuated by a standard servo. This requires some 3D-printed parts.