A high throughput optical system for imaging optodes

The objective of this study was to design a high throughput macro imaging system for intensity ratio based optodes, which facilitate both extensive replication and large number of samples to fulfill the statistical requirements for understanding natural processes occurring over extended time. The suggested system accommodates up to 24 sample cells with a field of view of 35 mm or 12 sample cells and 12 calibration cells for a seamless replacement of the optodes to follow processes that last longer than the optode lifetime. The individual components such as sample turrets, LED light sources, filters and lens designs are tested and discussed in detail. Positioning and alignment of an adjacent cell is completed within 6 s with an accuracy of five pixels. The acceleration profile for the sample turret is software controlled, which makes it possible to study e.g. sediments with overlaying water without effects from re-suspension. Calibration is performed by simultaneous filling of all the flow-cells with calibration solution and thereafter a sample run is executed. Thus, the effort required for calibration is the same regardless of the number of sample cells used. The system is automated and controlled through Matlab (Mathworks Inc), which is also is used for post processing of the images. The system was designed for an environmental application where more than 2000 individual images were collected and calibrated to yield 360 sample images.