Fluorimetric determination of quinine using a portable system and digital image processing

The development of a portable device created by 3D printing for fluorimetric measurements is an efficient tool for analytical applications in situ or in the laboratory presenting a wide field of applications in the environmental and food field. This device uses a light-emitting diode (LED) as radiation source and a digital microscope as a detector. Digital images obtained by the interaction between the radiation source and the sample were analyzed with the help of the YouCam software, the images were filed in JPEG format and processed with the Chemostat software.The entire system is connected to a notebook, which serves as a LED and detector power supply without the need for any additional power source. The proposed device was used for the determination in situ of quinine in water and beverages samples, respectively. For the validation of the developed system, the results obtained were compared with a conventional spectrofluorometer with a t-test at a 95% confidence level. The proposed system provides satisfactory precision and accuracy values. The proposed method presented detection and quantification limits of 0.99 and 1.46 mg L⁻¹, at a 95% confidence interval.