Colorimetric determination of formaldehyde in water

The procedure concerned is based on the formation of an intensely pink dye between the analyte, p-rosaniline and sodium hydrogen suiphite. No sample pretreatment is required. 

The workstation used for this determination [15] is depicted schematically in Fig. 9.7 and consists of the following components  

During the time each sample is allowed to stand before being measured, the robot treats other samples in sequence. 

This example is illustrative of a not very complex determination in which the use of a robot is recommended when the sampling rate required is not very high. The water samples are placed in the rack as they are received in the laboratory. When a reasonable number of them has been gathered, the station is set up to perform the above-described operational sequence. In the meantime, the robot can be used for other applications. 

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Fig. 9.7 Robot station for colorimetric determination of formaldehyde in water. (Courtesy of Zymark).

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