A flow cell with a new design to improve the utilization of the radiation emitted by LED and employed as a radiation source for photometric detection

This work encompasses a flow cell, designed to improve the utilization of the radiation beam, emitted by light emitting diode (LED), a multicommuted flow analysis module and a LED based photometer. The setup was designed in order to verify if a LED based photometer obeyed the Bouguer–Lambert–Beer law, while varying the length of the flow cell. The photometric assays were accomplished, employing as a model, the compound formed reacting iron (III) with thiocyanate in acidic medium. Assays were performed by varying the optical pathlength of the flow cells from 50 to 200 mm. This showed an increase in sensitivity of four-times, thereby indicating that the Bouguer–Lambert–Beer was obeyed. This allowed facilities to obtain a wide linear response range (0.025 up to 2.50 mg L−1 Fe (III), r = 0.9999), a low limit of detection (0.01 mg L−1 Fe (III)), a reagent consumption of 8 mg KSCN per determination, and an analytical throughput of 125 determination per hour.

Graphical abstractView of the flow cell and its assembling to the LED and the photodetector.Figure optionsDownload full-size imageDownload as PowerPoint slide